P0172, fuel in oil, Rough idle, engine run-on GM? (Professionals recommend)

Diagnose and fix P0172, fuel in oil, Rough idle, engine run-on GM. GM has determined that a P0172 System Too Rich (Bank 1) may be caused by a defective high-pressure fuel pump that’s leaking fuel into the crankcase when the plunger is depressed.

  • P0172 is thrown when the oxygen sensors detect that the air fuel mixture is too rich. Bank 1 refers to the rich condition being detected on the side of the engine with cylinder 1. A rich condition indicates that the air fuel mixture has too much fuel or not enough air. This would be the opposite of a lean condition, which’ll throw P0171.

What causes System Too Rich Bank 1?

What Does System Too Rich Bank 1 mean? System too rich bank 1 means that the oxygen sensor in bank 1 identified a rich situation (presence of inadequate amount of oxygen in the exhaust). The engine control unit constantly monitors and communicates with different sensors of the fuel injection system / fuel trim.

How do I fix the engine code P0172?

What repairs can fix the P0172 code?

  1. A repair of a vacuum leak.
  2. A replacement of a faulty fuel injector, fuel pump, or fuel regulator.
  3. Replacement of an excessively restricted air filter.
  4. Replacement of the thermostat or coolant temperature sensor.
  5. A replacement of the spark plugs.

What causes system too rich?

Rich mixture conditions are often caused by insufficient air entering the engine. The first thing to inspect is the air filter and the entry air flow to ensure all is clear. An exceptional dirty air filter that is very restricted can cause both codes to set.

Can I drive with a P0172 code?

It is okay to drive a vehicle with P0172 for a short period of time, but driving with this code for an extended period of time can cause internal engine damage and failure of the catalytic converter.

Can a bad O2 sensor cause a car to run rich?

The O2 sensors are located on the exhaust pipe to sense the air-fuel mixture from the previous combustion. A faulty O2 sensor can cause the engine to run too rich.

What does bank 2 System too rich mean?

When your vehicle displays a P0175 code, it means that the air/fuel ratio of the engine is running too rich in bank 2. Bank 2 is the side of your engine block that does not contain your #1 cylinder. An engine runs too rich when there’s too much fuel and not enough oxygen.

Will fuel injector cleaner help O2 sensor?

Will fuel injector cleaner help o2 sensor? – Quora. Nope. O2 sensors are like spark plugs in that they last a long time but eventually need replacing.

How do you fix fuel mixture imbalance?

Repair or replace the quirky wiring and/or connectors. Rehabilitate the leakages in the engine exhaust. Carefully adjust the faults in the mass air flow or manifold air pressure sensor. The blocked fuel filter should be restored to working order.

How do you fix rich air/fuel mixture?

You can apply these methods described here to fix the rich mixture problem:

  1. Check The Air Duct’s Flap. The flap inside the air duct is an actuator that serves as choke.
  2. Vacuum Lines And Hoses.
  3. Clean The Mass Airflow Sensor.
  4. The Oxygen Sensor.
  5. Change the spark plugs.

What does code 172 mean?

Diagnostic trouble code (DTC) P0172 stands for “ Fuel System Too Rich (Bank 1)”. Your car’s computer will set the code when it determines that there’s too much fuel (or too little oxygen) in the engine’s air-fuel mixture.

Why is my truck burning rich?

When a car is running rich, it means the engine is receiving too much fuel and too little air. If it’s dirty and clogged with debris, air won’t be able to pass through the filter, thereby preventing it from reaching the engine. Fuel injectors stuck in the open position can also cause an engine to run rich.

What is code P2188?

The P2188 “ System Too Lean at Idle Bank 1 ” definition indicates that there is too much air and too little fuel in the air-fuel ratio detected by the ECM during engine idle.

What code is P0174?

Diagnostic trouble code (DTC) P0174 stands for “ System Too Lean (Bank 2).” The code indicates that your car’s computer has detected a lean running condition.

P0172, fuel in oil, Rough idle, engine run-on GM

It is because of all of the people on this site who have shared their expertise that I was able to figure out how to remedy this problem. Recently, my truck has been behaving strangely, surging at idle for a couple of weeks. someone appeared to be stomping on the gas pedal a lot While it first started, it only happened when the car was cold, but the problem has become worse, and today it started dying at idle and throwing the code p0123 (tps voltage too high), which is deceptive. In fact, I had previously updated the tps approximately 6 weeks prior, which had alleviated some surges on the cruise.

Someone advised washing it, but for $45 it didn’t seem worth the effort to me!

Overall, it was a really straightforward process.

air cleaner must be removed Disconnect the three sensor wiring connectors from the throttle body and set them aside.

  1. IAC in the back.
  2. They were easily removed.
  3. The two cables on the exterior may be removed by pressing away from the cable’s direction and they will just pop out.
  4. The three bolts holding this bracket to the tb should be removed and the bracket should just fall off the side of the tb.
  5. the four bolts that hold the transmission in place must be removed after that 13mm.
  6. I gently loosened them in a cross pattern, one small adjustment at a time.
  7. Take care not to damage the throttle body gasket or drop anything into the intake.

Return to the plenum and have a look at the floor.

It’s a major project that should be left for another day.

With a Torx25, remove all three sensors while keeping the bolts in their original positions.

This morning, my iac was completely clogged.

Scrub the whole tb with a toothbrush and finger after spraying it with carb cleaning, paying special attention to the 2 or 3 little tubes, the plates, the huge holes in which the plate pivots, and other areas that need to be thoroughly cleaned.

When it comes to fitting in the well, it should be snug and not make any touch at all until the end.

Put in a tps and a front sensor (dont forget the little hose).

Please double-check that the gas pedal works well, since mine wasn’t working properly due to a faulty wire.

I had mine whistle like a madman and idle at a high speed for approximately 30 seconds while it established the iac position, after which it operated normally. Cleaner should be reinstalled. go for a spin your work is admirable

Also interesting: P0172, fuel in oil, Rough idle, engine run-on GM? (Professionals recommend)

Vehicles affected byPIP4783B

2010-2012 The engine of the Buick Lacrosse is a 2.4L. 2011 2012-2017 Buick Regal with a 2.4L engine Buick Verano with a 2.4-liter engine 2012-2016 The 2.4L engine in the Chevrolet Captiva 2010-2017 Chevrolet Equinox with a 2.4-liter engine 2010-2017 2020 GMC Terrain with a 2.4L engine Rick Muscoplat is a professional musician. Rick Muscoplat posted a blog entry on

P0172 Code: System Too Rich Bank 1 (Symptoms, Causes, and Fixes)

The most recent update was made on June 11, 2020. The internal combustion process is centered on the interaction of air and fuel. If the ignition is to be effective, it is necessary that the right amount of air and fuel be introduced into the internal combustion chamber. Other than that, you can find yourself in a position where your engine either uses too much gasoline or performs below par. Are you looking for a reliable online repair manual? The top five choices may be found by clicking here.

This is the vehicle’s main computer, which controls practically all of the vehicle’s internal processes, including how much gasoline is fed into the combustion chamber at any one time.

P0172 is generated by the ECU as a result of this situation.

What Does Code P0172 Mean?

P0172 is an OBD-II trouble code that has a description. System that is overly wealthy (Bank 1) It is continually monitoring and talking with the sensors of your fuel injection system, which is controlled by your engine control unit. If the powertrain senses that there is an excessive amount of fuel in the combustion chamber, the diagnostic trouble code (DTC) P0172 will be shown on the dashboard. There are a variety of sensors and equipment that are used to determine the amount of fuel present in the chamber’s exhaust gases.

  1. When there is an excessive amount of fuel, there is an insufficient amount of oxygen.
  2. The oxygen sensors in this cylinder are responsible for measuring the amount of oxygen present in the exhaust gases.
  3. For most gasoline engines, the usual compression ratio is 14.7:1.
  4. If the engine management unit determines that the bank 1 cylinder is ‘too rich,’ it signifies that it has received an excessive amount of fuel and not enough oxygen.

Symptoms of Code P0172

The symptoms of problem code P0172 are frequently the same as the symptoms of an engine that is running too rich in fuel.

In most cases, your check engine light will be on (unless the bulb is burnt out). However, there are certain extra signs and symptoms to be aware of:

  • The exhaust has a strong gasoline or rotten egg smell to it. Unsatisfactory fuel efficiency
  • Engine hesitation
  • Engine misfiring
  • Lack of power when driving
  • Rough idling

Causes of Code P0172

There are a variety of possible causes for this condition to arise. Most commonly, a malfunctioningoxygen sensor or a filthy mass air flow sensor are to blame for the problem (MAF). In addition, the following are some other reasons for the code PO172 to be thrown.

  • Failure to properly maintain the fuel injectors, resulting in gasoline entering the combustion chamber
  • Failure to properly maintain the spark plugs
  • Failure to maintain the manifold absolute pressure sensor (MAP)
  • Failure to maintain the throttle position sensor Air filter that is dirty or blocked
  • Vacuum leak
  • Faulty ECU (or PCM module)
  • Faulty fuel pressure regulator
  • Faulty thermostat (which is jammed open)
  • Faulty fuel pressure regulator A cooling system that has been retrofitted (for example, the thermostat has been removed, the fan is operating directly, etc.)
  • Fuel line that is restricted or damaged

How to Fix

The presence of faulty ignition components, such as defective spark plugs, a malfunctioning manifold absolute pressure sensor (MAP), and a malfunctioning throttle position sensor, are all causes of the vehicle’s failure. Filter that is dirty or clogged; vacuum leak The fault lies with the ECU (or PCM module); the fault lies with the fuel pressure regulator; the fault lies with the thermostat (which is stuck open). A cooling system that has been retrofitted (for example, the thermostat has been removed, the fan is running directly, and so forth).

2016 Chevy Equinox 2.4 Ecotec – P0172 – Dieseling

My Equinox started throwing the P0172 code about a week ago. I am not the sort of person that will put off any form of problem or maintenance on my vehicle. I cleaned the mass air flow sensor that night (I started with the cheapest of ideas) and that did not resolve the problem with the light or the dieseling (a phrase I didn’t realize I was using until I was working on plan of attack3). In addition, the throttle body was cleaned for good measure. At this point, I was perplexed and spent the better part of the next day attempting to figure out what was going on, whether it was dieseling or a run-on.

  • There was a supply of gasoline on hand.
  • I also put seafoam through the system just in case the injectors were clogged with gunk.
  • However, it is doing it again, albeit not as badly as before.
  • What is the recommended interval between oil changes for this particular issue?
  • information on the side Every 3,000 miles, I replace the oil in my car.
  • I’m quite conscientious about upkeep and keeping track of it.
  • Any advise would be very appreciated as I feel like I could smash my head against the wall if I am unable to completely handle the situation.

P0172 – Meaning, Causes, Symptoms, & Fixes

Bank 1 either has more fuel than it should or does not have enough air to operate properly.

What Does P0172 Mean?

Combustion engines operate most efficiently when the air-to-fuel mixture ratio is maintained at 14.7 parts air to one part fuel. The presence of a rich situation is indicated when the upstreamoxygen sensor detects that there are fewer than 14.7% air to one part fuel in the air-fuel mixture.

Powertrain control module (PCM) attempts to adjust for the rich state by injecting a less amount of fuel into the mixture in an attempt to maintain the appropriate 14.7:1 air-fuel ratio. When the magnitude of these modifications exceeds a certain threshold, code P0172 is triggered.

What Are the Symptoms Of P0172?

  • Check Engine The light is on
  • The engine is not producing enough power
  • The engine is hesitating
  • The engine is misfiring
  • There is a strong gasoline smell coming from the exhaust

What Is The Cause Of P0172?

  • Whether it’s dirty or defective MAF sensor failure
  • Oxygen sensor failure
  • Sensor failure for air-fuel ratio
  • MAF sensor failure Fuel injectors that are leaking and enabling an excessive amount of fuel to enter the combustion cylinders Spark plugs that have become worn
  • Fuel pressure regulator that is stuck
  • Coolant temperature sensor that is faulty
  • Coolant thermostat that is faulty

How Serious Is Code P0172? – Moderate

Driving a car with the P0172 code for a short amount of time is OK; however, driving a vehicle with this code for a longer period of time might result in internal engine damage and the failure of the catalytic converter.

Code P0172 Common Diagnosis Mistakes

When diagnosing P0172, it is critical that the full diagnostic process be completed in its entirety. Many people will immediately replace the air-fuel sensor or oxygen sensor if they receive a bad reading; however, the root cause is frequently a dirty or faulty Mass Air Flow (MAF) Sensor or vacuum leak, which causes the O2 or A/F sensor to read differently to compensate for the dirty or faulty MAF Sensor. The ability to read and analyze gasoline trims as well as freeze frame data is essential for correctly diagnosing P0172.

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Tools Needed to Diagnosis Code P0172:

  • The following tools are required: a vehicle repair manual, FIXD, screwdriver, pliers, a fuel pressure gauge, and Mass Air Flow (MAF) sensor cleaning.

How To Diagnosis Code P0172?

  1. P0172 is the only code that should be present, therefore scan your car using FIXD to confirm. If there are any additional codes present, they must be dealt with first. Ensure that there are no obstacles in your air intake box or air intake pipe that might limit proper airflow in your vehicle’s engine. Inspect your air filter to verify that it is not clogged and that it is correctly placed
  2. Remove the Mass Air Flow (MAF) Sensor and clean it with a mass air flow cleaner to ensure that it is free of contaminants. Repair and replace the Mass Air Flow (MAF) Sensor, as well as reset the check engine light, using FIXD. The diagnostic procedure should be repeated if the check engine light comes back on and displays code P0172. If the check engine light code P0172 continues to illuminate even after you have inspected and cleaned the Mass Air Flow (MAF) Sensor, you should run a fuel pressure test on the vehicle. If any of the components in the fuel system are deteriorating, they should be replaced as soon as possible. Make sure you pay close attention to the fuel pressure regulator and the fuel injectors in particular. Because of the high pressure created by a faulty fuel pressure regulator, a rich state might result if the regulator becomes stuck. Fuel injectors that are not functioning properly may leak fuel into the cylinders rather than providing the precise amount required for the proper air-fuel ratio. Check to check that your coolant temperature sensor and coolant thermostat are both operating correctly before continuing (see steps 3 and 4 of P0128). The vehicle will remain in a ‘open-loop’ operation if any of these components fails to work properly. The vehicle will continue to supply a fixed rich mixture if either of these components fails. The oxygen sensor(s) and/or A/F sensor(s) should be replaced if the check engine light continues to illuminate after completing this diagnostic procedure. You can check to see whether the problem is with the oxygen sensor. This is a fantastic video that fully describes the procedure
  3. Click here.

Estimated Cost of Repair

If you receive error code P0172, one or more of the fixes listed below may be required to resolve the underlying problem. The estimated cost of repair for each feasible repair includes the cost of the essential components as well as the cost of the labor required to complete the repair, if any.

  • Fuel pressure regulators range from $200 to $400, while air fuel sensors and oxygen sensors cost $200 to $300. Thermostats cost $200 to $300, while engine coolant temperature sensors cost between $150 and 200 dollars.

P0172 – System too rich, bank 1 – TroubleCodes.net

Trouble Code Fault Location Probable Cause
P0172 System too rich, bank 1 Intake blocked, EVAP canister purge valve, fuel pressure, EGR system, injector(s), HO2S

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What Does Code P0172Mean?

In order to give the optimum power and fuel economy, your engine must put in the appropriate quantity of gasoline in relation to the amount of air entering into it, which is known as the optimal air-fuel ratio. The ECU (engine control unit) determines how much gasoline to put in the engine by analyzing data from a variety of sensors, including the MAF, CKP, and ECT (mass air flow, crankshaft position, and engine coolant temperature). The ECU may fine-tune the fuel injector pulse-width (IPW) based on data from the HO 2 S, AFR (heated oxygen sensor or air-fuel-ratio sensor), or Lambda sensor to produce the ideal air-fuel ratio for the given conditions.

As a result of combustion, a tiny quantity of oxygen from the air is utilized to oxidize the fuel, leaving a small amount of oxygen in the exhaust, which the HO 2 S detects and reports back to the ECU through a signal wire.

In contrast, if there is very little oxygen present, this indicates that the engine is running rich, indicating that too much gasoline has been put into the engine.

Typically, fuel trims will be within 3 percent of the optimal range, depending on factors such as current air and coolant temperatures, as well as engine load.

It will attempt to compensate by lowering IPW, but if fuel trim exceeds -25 percent or so, the ECU perceives this as a fault and sets the DTC P0172 – Fuel System Too Rich (Bank 1), as well as illuminates the MIL or CEL (malfunction indicator lamp or check-engine light).

What are the common causes of code P0172?

DTC P0172 can be caused by a variety of factors that vary depending on the year, manufacture, and model. Here are a few of the most often encountered.

  • Toyota / Lexus – MAF that has been contaminated, mainly via the use of aftermarket filters. Although the exact cause of this association is unknown, certain Toyota hotwire MAFs are particularly prone to contamination, according to the manufacturer. Cleaning seldom has positive results. Remove the old MAF and engine air filter and dispose of them. Make sure that the air box seals well before cleaning it and installing the replacement MAF and air filter, which should preferably be OEM components. Blower-by engines, whether by design or by age, may let oil to enter the air box and, as a result, the air filter and mass air flow sensor (MAF) may get oiled. Some aftermarket air filters also require oil treatment in order to function properly, which some owners may be excessive in adding to their filters. In either situation, an excessive amount of oil can contaminate the MAF, resulting in inaccurate air flow measurements. Ensure that the PCV and tubing are in proper operating condition as well as the rest of the system. The presence of dirt – In a perfect world, your engine bay would be impeccably clean. But as time goes on, dirt and grime accumulates, and it is quite easy for it to make its way into the engine and control systems. For example, older and neglected automobiles are more susceptible to MAF contamination due to excessive dust and debris or a poorly-sealed air box. Fuel Injector that is leaking – If a fuel injector is leaking due to age or pollution, it will pour fuel into the cylinder even when it is not being used. If there is a strong odor of gasoline in the oil, this is a good indication of fuel leakage. A leaking fuel pressure regulator has been seen in some automobiles equipped with vacuum-operated fuel pressure regulators, allowing unmetered gasoline to enter the intake directly.

What are the symptoms of code P0172?

In some cases, DTC P0172 may or may not be accompanied by drivability concerns, depending on the type of the failure and the severity of the failure. At the absolute least, you may suffer poor fuel efficiency because the ECU is no longer searching for feedback from the HO 2 S and AFR sensors while in ‘limp-home mode.’ Rough idling, a lack of power under acceleration, and even misfiring or stalling are all possible symptoms of a cold engine, and these symptoms will become worse as the engine warms up.

Additionally, you may notice a strong gasoline odor as well as black soot in the exhaust tip or rear of the vehicle, which is an indication that a large amount of unburned fuel is making its way through the system.

How do you troubleshoot code P0172?

It is important to remember that the Fuel Trim Monitor will not run until the HO 2 S monitors have run and passed. This is important to remember when diagnosing fuel trim problems. The fuel trim monitor operates on the basis of the oxygen sensor, which means that fuel trim codes are not the same as oxygen sensor codes.

  • P0172 in conjunction with P0175 or MAF DTCs – In the event that you encounter both P0172 and P0175, as well as concurrent MAF-related DTCs, you may very certainly rule out individual cylinder, ignition, and fuel injector issues. Instead, concentrate on the fuel injection system and the mass air flow meter.
  • MAF contamination might cause inaccurate air intake readings, which would result in inaccurate fuel injection calculations. It is possible that cleaning will solve the problem. A more permanent option would be to replace the unit, coupled with a new air filter and a properly sealed air box. Verify that the fuel pressure is within the correct range by checking the gauge. Increased pressure, such as that generated by a faulty pressurization regulator or a pinched return line, would result in the injection of more gasoline than the ECU had anticipated. Check that the ECT and IAT (intake air temperature) measurements are correct. Because the ECU may or may not detect stuck sensors, it is a good idea to double-check that the ECT and IAT readings are within normal limits. The engine coolant temperature (ECT) should be at least 175 degrees Fahrenheit if you’ve been driving for half an hour on a hot day. If the temperature remains at 32 degrees Fahrenheit, the ECU will increase the AFR to compensate, resulting in a rich situation.
  • P0172 in conjunction with other Bank 1 DTCs – If you only notice P0172 and no other contemporaneous Bank 1 DTCs, such as a cylinder misfire, concentrate your attention on Bank 1.
  • Drop in Fuel Pressure — While the engine is running, record the fuel pressure and then turn off the engine. It is possible that the fuel pressure will decrease somewhat, but it should remain constant for at least 10 or 15 minutes. if the fuel pressure continues to drop, it is probable that you have a leaky fuel injector, which would result in a rich situation as well as a possible misfire issue. Misfiring Cylinder – A misfiring cylinder would cause unburned gasoline to escape into the exhaust stream. Before attempting to diagnose and fix a cylinder misfire, it is necessary to first identify and correct a rich condition. Pay close attention to any DTCs that appear at the same time, such as those related to VVT (variable valve timing) or the ignition system. Examination of the exhaust system for leaks between the cylinder head and oxygen sensor is recommended. Despite the fact that the exhaust system seems to be a positive-pressure system, air can enter through a partial vacuum caused by the pressure pulses generated by the exhaust. The presence of atmospheric oxygen entering before the HO 2 S might cause oxygen content readings to be skewed.

Codes Related to P0172

While diagnosing DTCP0172, you may come across the following additional diagnostic trouble codes:

  • P0170– Fuel Trim Malfunction (Bank 1)
  • P0173– Fuel Trim Malfunction (Bank 2)
  • P0175– Fuel System Too Rich (Bank 2)
  • P0101– Mass Air Flow Circuit Range / Performance
  • P0104– Mass Air Flow Circuit Intermittent
  • P030x– Cylinder Misfire Random or Specific
  • P030x– Cylinder

Other DTCs related to the fuel system may include the following, which are on the opposite end of the spectrum:

  • P0171– Fuel System Too Lean (Bank 1)
  • P0174– Fuel System Too Lean (Bank 2)
  • P0175– Fuel System Too Lean (Bank 3).

BAT Team Discussions for P0172

  • P0172 Malibu DTC 99 Malibu I’ve posted this question a few of times without receiving any responses. Despite the fact that I have been working on automobiles for a very long time, this one is causing me to lose my hair. I even brought it to my friend’s shop and left it there for a couple of weeks while he worked on it. Here’s some further information. Honda 2000 Odyssey
  • 1999 Chevrolet Malibu LS, 3.1L, automatic
  • 1999 Chevrolet Malibu LS, 3.1L, automatic 0172-0170-1491-030 . codes This has been going on for quite some time now. I currently have 107,000 miles on my car. System too rich (bank 1) is the most common DTC, followed by P0170 Fuel trim (bank 1) and, on rare occasions, 1491 EGR valve lift sensor inadequate flow detected (all of which cause a freeze frame). If I leave it for an extended period of time, I begin to receive codes. The Volvo Engine Trouble Code is P0300-04-05. On my non-turbocharged 1997 Volvo 850, I constantly receiving the following codes: P01002-MAF or VAF circuit low input
  • P0440- Evap emission control malfunction
  • B0300 Random Cylinder misfire
  • P0172- Sys too rich. Bank 1 is the first of the three banks. I’ve replaced the plugs and cables. Distributor caprotor is a kind of caprotor. Idles are a little harsh at first, but they level out
  • The 98 Accord is throwing out codes. My friend owns a 1998 HONDA ACCORD EX, 2.3L L4 SFI OHV, VIN 1HGCG565XWA099150, with 150K miles on it, and the vehicle is emitting the following codes: P0172 P1457 P0170 P0172 P1457 P0170 He informs me that the person at AZ told him that they were all connected to gasoline. I checked them up, but I’m not sure where to begin with them. Can somebody direct me in the proper direction? Honda Accord (model year 2000) In my 2000 Honda accord, the engine has a hard time starting and, when I step on the gas, the engine stutters and looks to be near to stalling while I’m attempting to move the vehicle. It is possible that the engine will stumble a little when driving. The same thing has been going on for a number of years now.

P0172 and P0175: System Too Rich

The code P0172 indicates that the fuel mixture in Bank 1 of the engine is too rich. P0175 indicates that the fuel mixture in Bank 2 of the engine is too rich. Engine Cylinder 1 is located on the same side of the engine as Engine Bank 1. Engine Bank 2 is located on the opposite side of the engine from Engine Bank 1. It may be necessary to consult a firing order and cylinder placement diagram in order to determine whether side of the engine is Bank 1 or Bank 2. P0172 is activated by the ‘upstream’ oxygen sensor in engine bank 1, and P0175 is triggered by the ‘upstream’ oxygen sensor in engine bank 2, respectively.

  1. The symptoms and causes will assist you in determining the specific nature of the problem and how to resolve it.
  2. Those sensors that are located near the engine and before the catalytic converter are referred to as ‘upstream,’ or ‘upstream sensors.’ Sensor 2 is located ‘downstream,’ or immediately after the converter.
  3. This is accomplished by the transmission of a constant but changing voltage signal to the computer.
  4. A low voltage measurement that remains constant suggests a lean fuel mixture.
  5. In this case, the ideal ratio is 14.7:1.
  6. According to the nature of the problem, if the fault is generating a rich state on both engine banks, it may set both codes.
  7. What makes this code difficult to decipher is that if it appears by itself, it is not a monitored component that has failed, else it would also get a code.

Overall, the engine is running rich, but the computer cannot determine why because there are no other fault codes associated with it. Check the status of your check engine light.

What are Common P0172 and P0175 Symptoms?

There are several cases where engine performance concerns do not manifest themselves. The following performance issues can occur in your car if you use too much rich gasoline, however:

  • Strong odor of exhaust fumes
  • Black smoke emanating from the exhaust pipe
  • Increased fuel consumption
  • Decreased power
  • Rough idle
  • Engine oil dilution with gasoline
  • Increased emissions.
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This time around, similar symptoms are usually accompanied by an illuminated Check Engine Light. Look for one of these typical reasons to figure out how to fix the problem code you’re having. The first thing to check is whether or not there are any additional codes present. If any (or both) of these codes appear at the same time as, for example, a mass air flow sensor code, it is reasonable to believe that the MAF sensor is the source of the rich situation in question. If either P0172 or P0175 appears on its own, or if both codes are saved, you have an issue that necessitates more detective work, and you must go outside the sensors and things monitored by the engine’s computer to find the source of the problem.

Causes of P0172 and P0175

There are a variety of minor and significant fixes that might result in this problem. Start with the simplest difficulties and work your way through the list until you’ve identified the root cause of your error code. When there is inadequate air entering the engine, rich mixture circumstances are frequently seen. The first item to check is the air filter and the entering air flow to confirm that everything is in working order. Both codes can be set by a particularly unclean air filter that is extremely limited in its flow.

If nothing appears to be wrong here, it is possible that there are other, more serious problems going on.

It’s important to note that fuel issues such as these will almost always result in a misfire code, which can be either random or specific to a specific cylinder or a combination of both.

Extended driving with a low cooling system temperature will extend the pulse time of the fuel injector, resulting in more fuel being delivered.

How to Fix P0172 and P0175

It is possible to clean the MAF sensor if the cooling temperature is good, the air filter is clean, the engine oil is not diluted, and there are no other trouble codes. If the cooling temperature is good, the air filter is clean, the engine oil is not diluted, and there are no other trouble codes, you may try cleaning the MAF sensor. A thorough maintenance cleaning is usually recommended, especially when replacing an air filter, regardless of whether this is the problem. Don’t put off getting this problem resolved any longer.

If you want expert assistance, please see our list of Preferred Repair Shops in the surrounding region.

2.2 Running Rich, stumping mechanics everywhere!

Okay, I’ve been working on the S10 for the entire day. Here’s what’s new in the world of technology. The alternator and battery have been changed, and the purge valve has been tested and found to be in good working order. The IAC and throttle body passenges are both quite clean. I checked all of the ground connections on the block, firewall, rad support, and frame; they appeared to be in fine condition; but, I removed them, cleaned them, and retightened them nonetheless. The air filter has also been replaced, and all of the ducting has been cleared of blockages.

  • The connection remained active for the whole time it ran (15 minutes), although the inside lights flickered briefly for around 2 minutes after starting up, after which the flickering stopped and the lights remained consistent.
  • As soon as I tap the throttle in closed loop, the engine starts to choke a small bit for a millisecond, revs high, and then the rpms plummet hard for a fraction of a second before smoothing out again.
  • In addition, I noted three things.
  • I notice that my MAP voltage drops as I crank the engine!
  • 3.
  • The intake manifold will have to be removed with the injectors still connected in order to visually check for leaks with fuel pressure; how will I accomplish this with the hard fuel line running to the manifold attached to the engine?
  • Also, can a junkyard pcm that is the same year, engine, and tranny fit right in?

Multiple codes – hard cold start

For some changes and more queries, I’m republishing this post: 1. After a few of months of investigation, there are just too many alternatives for P0172 and P0175. The first is a potential intake leak, which I did not meddle with at the time, but am looking for today. 1b. The fuel trim has to be adjusted – this has been accomplished. 1c. Reset the alcohol content reading in the PCM – this task has been done. 1d. Dirty MAF and/or TB – both were cleansed with the appropriate cleaners. 1e. Clogged air filter – air filter was changed.

  1. Bad oxygen sensors – hardly likely, hence they were not replaced.
  2. My snap-on solus pro was used to reset the alcohol content and fuel trim settings, which I found very useful.
  3. I replaced the connectors, wires, and air filter, as well as cleaning the MAF and TB.
  4. Smog/crud had accumulated on the plugs’ surfaces, and several of them had oil around their threads.
  5. I drove the truck without incident, although the cold weather has passed (low 60’s today), compared to when all of the problems were occurring (single digits, sub-zero temps).
  6. As a result of all of the foregoing, the vehicle is now running lean, despite the fact that the check engine light did not illuminate on the dash.

Although technically not applicable to the year of Silverado I am currently working on, this is an interesting read: Subject:Check Fuel Alcohol Value due to DTCs P0172 and/or P0175 – Check SES LightModels:2010 Cadillac Escalade SES Light owing to DTCs P0172 and/or P0175 – Check SES Light Chevrolet Avalanche, Express, Silverado, Suburban, and Tahoe models from 2009 to 2010.

  1. having an L20, L77, or L94 RPO code on a V8 engine; or having the following V8 engine RPO codes: LC8, LH8, LMF, or LMG.
  2. Step 4 was introduced to alleviate this problem since, if the ethanol learn occurs during a cold start, a service calibration will not be released to fix the issue.
  3. PIP4792 should be discarded.
  4. Condition/Concern: A hard start cold, a brief rough running on a cold start, a black exhaust color, and/or a SES light may be experienced by a small number of consumers on rare instances.
  5. If any driveability issues are noticed, they will typically subside within 1 minute of the vehicle being started.
  6. If this is the case, the ECM computed alcohol percent may be verified by showing it on the scan tool and comparing it to the previously known alcohol content of the gasoline as detected by the J44175 fuel composition tester.
  7. This may cause the engine to misfuel, which may eventually result in the problem described above.

As described in the Fuel Composition Diagnosis, the concern can be resolved by resetting the fuel alcohol value and fuel trims as described in the Fuel Composition Diagnosis.

If they have, tell them that it is better not to switch back and forth between ordinary gasoline and E85 on a frequent basis.

They should also drive the car for at least 7 miles (11 kilometers) soon after refilling to allow the vehicle to become acclimated to the difference in the amount of ethanol in the gasoline.

Ensure that there are no vacuum or air leaks in any vacuum hoses, the whole air intake system, the dipstick seal, the oil fill cap/tube seal, the PCV system, and the valve covers.

As a result of the skewed input from the MAF sensor, inspect the air filter, air intake, and MAF sensor to confirm that they are all OEM and that there is no evidence of debris (leaves, pine needles, etc.) or casting flashing, which might be causing this.

Assess the customer’s habit of filling the fuel tank before to reaching operating temperature or of immediately parking the vehicle for an extended length of time after filling the fuel tank.

As an illustration, the following are some filling practices that may allow the alcohol learn process to occur during engine warming: Beginning with a cold start, driving right to a local gas station, filling the gasoline tank, and then restarting the engine from the cold start.

If these filling habits are a factor, the problem can be avoided by filling the gasoline tank while the engine is running at normal operating temperature and traveling at least 7 miles (11 kilometers) before parking the car.

It is not necessary to complete the remaining stages if the condition indicated is resolved without completing all of the measures listed above.

Specifically, they are created in order to alert these professionals of situations that may develop on certain cars, or to offer information that may be useful in the correct service of a vehicle.

In the event that a condition is stated, DO NOT assume that the advisory relates to your vehicle or that your vehicle will be affected by the condition. Inquire with your local General Motors dealer to determine whether your car might benefit from the information.

Diagnosing Rough Idle On Chrysler 2003 Town & Country

Considering our improved economy, it is realistic to state that many car owners are still forced to balance auto maintenance with their other financial obligations. More information is available by clicking here. It’s not uncommon for car owners to be unable to fix a bright-orange Check Engine light in a timely way due to unforeseen circumstances such as a dental appointment or a hot water heater that has just burst its seams. When the maintenance-based and component-based failure lights come on, the driver has no way of predicting how many failures will collect before he or she can afford to have a certified technician come out and look at the vehicle.

  1. In the midst of a flurry of summer business, the shop’s staff was unable to figure out what looked to be a bizarre mix of symptoms.
  2. While driving the car, the idle condition deteriorated to the point that the engine would not idle in gear unless the driver pressed the accelerator.
  3. This assumption proved to be incorrect.
  4. The technician changed the spark plugs after a cursory visual assessment indicated that the spark plug wires and spark plugs looked to be original equipment.
  5. The fact that the short- and long-term fuel trims were both negative suggested that the PCM was removing fuel.
  6. 0.090′ spark plug spacing were being pushed, which is 150 percent of the original standard.
  7. In order to rule out oil fouling on the cylinder 4 plug, the technician checked compression on the engine’s front bank, which revealed that all three of the engine’s front cylinders were normal.

I almost always start any diagnostic with a scan tool, which I use to check all modules for DTCs and to look for anomalies in the data stream before proceeding.

The engine was brought under fuel control when the purge hose and brake booster hose were disconnected from the evaporative system.

The spark plug insulators in most contemporary engines that are functioning at operating temperature are almost always completely white in color.

I suspected that the rich state was caused by the cylinder 4 fuel injector, so I entered the Automated Testing Mode (ATM) and disabled each fuel injector while the engine was still running to confirm my suspicion.

Despite the fact that the engine idled more smoothly, the quality of the idle still prevented me from correctly evaluating the functioning of the fuel injectors.

This waveform for a single cylinder indicated that cylinder 4 was not receiving a powerful spark.

This was unexpectedly the case.

After repeated attempts at reproducing the stalling scenario, I came to the conclusion that the cylinder 4 injector was leaking fuel to its partner cylinders (see Figure 1).

In any event, there was still a noticeable miss while the engine was at idle.

As previously stated, the Chrysler was equipped with what seemed to be the original spark plugs and wires.

A damaged exhaust valve spring was discovered to be the primary cause of the rough idle situation on the 3.8L Chrysler van’s exhaust valve spring.

As I predicted, even with new spark plugs, the resistance of the spark plug wires varied depending on the condition of the plugs.

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By comparing the secondary resistance at the coil terminals of the three cylinders, it was discovered that the cylinder 3 and 6 coil had a substantially lower resistance than its companion coils.

Tomorrow is a new day.

On the one hand, I had a feeling it was the case, but on the other hand, it’s practically hard to identify beyond a few clearly failing components.

In this particular instance, both the short- and long-term fuel trims were well below 10%, which is considered to be within a normal range of fuel control.

Following that, I used my lab scope to confirm that the new spark plug wires and ignition coil had successfully restored a normal secondary pattern to all cylinders, including cylinder three, which had been completely non-functional.

Normally, at this point, I would have used a pressure transducer and a lab scope to check for irregularities in the intake manifold vacuum, but this wasn’t the case.

We noticed right away that the spark plug from cylinder 4 had become coated with soot once more, and that all compression readings were within normal limits for our altitude, as they had been previously.

Observations and Insights After solving any multiple failure driveability complaint, any diagnostic tech worth his salt will review his diagnostic strategy to see if he might have found a better way to the root cause of the problem.

While this combination of failures defies the odds, the fact of the matter is that it did happen.

Making an assumption based solely upon prior experience (aka The “Blue Car” Syndrome) often leads to mistaken results.

To recap the complexities of this multiple-failure diagnosis, the high secondary voltages created by the badly eroded spark plug gaps were more than enough to ruin an ignition coil.

In addition, disconnecting the evaporative purge line eliminated the possibility that the purge valve itself was stuck open.

Valve Seating Issues The question also arises about how a cylinder with a broken valve spring might pass a compression test.

During my General Motors dealership days, small-block Chevrolet engines were known for breaking valve springs at the bottom coil.

Although the 3.8L Chrysler engine is also known to break valve springs, the coil breaks at the top due to the “beehive” design of the valve spring.

At higher engine speeds, the leakage past the valve seat evidently wasn’t enough to create an engine misfire.

Or it might have showed up as an irregularity on a vacuum waveform displayed by a pressure transducer connected to a lab scope.

On the other hand, if we had replaced the valve spring first, the need to replace the bad fuel injector, spark plug wires and ignition coil would have remained.

The odd part of this valve seating condition is that many engines will pass a cranking compression test and a cylinder leakage test.

The spark plugs should be replaced at 30,000-mile intervals, but had been run 60,000-mile intervals.

The manufacturer’s TSB recommended changing the valve spring keepers to an updated design that provides more valve rotation.

Only time will tell.

Some techs have remedied this problem with an intake service while other techs have had to remove the heads for a complete valve service.

The problem is, this level of diagnostics does require a lot of practice before it can be used as a definitive level of diagnosis. In any case, the methods used to detect intermittent valve seat leakage will continue to evolve as diagnostic technicians become more aware of this issue.

Car Running Rich Explained and 5 Ways To Fix it

There are a number of events that occur every time you turn on your automobile engine. Engine movement begins when the spark plugs light it and the pistons and crankshaft begin to move. Most automobiles, on the other hand, are powered by either gasoline or diesel fuel. In order for this to occur, your vehicle must maintain a balanced ratio of fuel and air during combustion. The optimum ratio is 14.7:1, which is the most common. This equates to 14.7 parts air to 1 part gasoline. This is a difficult ratio for your vehicle to keep up with.

It indicates that you are burning a lot of gasoline when driving.

Sensors are installed at emission points, fuel injectors, and airflows, among other locations.

Signs that your car is running rich

As long as you are in control of the steering wheel, you and your car should operate as a unit. Your automobile will send you indications that you must precisely decipher in order to avoid a collision.

Check engine light

Nowadays, almost all automobiles are equipped with an onboard computer. When the check engine light on your car illuminates, it indicates that your engine is having difficulty starting or operating. If your car is equipped with an onboard computer, look for the error code P0172. This mistake indicates that the gases coming out of your exhaust tailpipe are high in gasoline. Its operation is straightforward. Instruments for collecting and storing data can be found in your Engine Control Unit (ECU).

Oxygen and mass airflow sensors are among the other types of sensors.

Pungent Smell

Your exhaust tailpipe will emit a strong odor, which you will be able to detect. There’s a rotten egg stench about it. It demonstrates that the surplus fuel is not being used. Because gasoline escapes from the manifold and enters the exhaust pipe, the combustion process is ineffective. Your vehicle is equipped with a catalytic converter, which burns off any surplus fumes. However, when the fuel mixture is overly rich in gasoline, the engine is unable to completely burn up all of the fumes.

High fuel consumption

You may have noticed that you are getting less gas mileage out of your tank than you were previously. It serves as an indication that you are burning more fuel than your vehicle requires. In contrast, it is usual for your automobile to consume more gasoline during the winter months. Cold temperatures cause your engine to operate at a slightly higher expense than it would in warm weather.

Poor engine performance

The engine is quite interesting. It simply requires four components to be operational in order for it to function. A mixture of air, fuel, compression, and a spark is used in combustion. When the engine’s performance is poor, it can only be attributed to one of these components being underperforming.

The fact that you have a healthy spark and that your compression is operating properly might suggest one of two things. You have either an excessive amount of air or an excessive amount of fuel leaking from your engine’s combustion chamber.

High levels of carbon monoxide emissions

When your automobile is running, the exhaust pipe emits very low quantities of carbon monoxide (CO). It is very natural. In addition, most states require all automobiles to pass a carbon monoxide emission test. If your car fails the emission test, it signifies that it is operating at a high rate of efficiency. Carbon monoxide is extremely detrimental to your health and well-being. If it manages to make its way inside your automobile, which has restricted air supply, it can have a neurological impact on you.

Rough idle

When your automobile is idle, its RPM gauge may display irregular readings at times. Additionally, your car will experience needless vibrations. It is frequently indicative of poor engine performance. It indicates that your vehicle is running at a high rate of fuel consumption.

Spark plugs with soot deposits

When your engine runs rich, carbon deposits build on the end of the spark plugs’ tails, which are difficult to remove. The soot will gradually spread to other engine components, causing them to fail. Impurities have a negative impact on the catalytic converter. Carbon deposits are formed as a result of unburned fuel. When the surplus gasoline is introduced to the catalytic converter, it contains contaminants. Sooner or later, you’ll have to disassemble it in order to clean it or replace it.

Causes of Engine Running Late

You should check if any of the following equipment are malfunctioning if you believe that your engine is running rich.

Faulty Oxygen Sensors

It is the exhaust pipe that contains oxygen sensors. They are able to detect the air-to-fuel combination produced by burning. If the sensors choose an unusual combination, they send the information to the ECU, which processes the information. The ECU corrects the imbalance in the future engine combustions by adjusting the ignition timing. Because to a defective sensor, the car will operate at an excessively high rate of speed.

Faulty Mass Air Flow Sensor

Basically, it is in charge of monitoring the amount of air that enters the engine. Following each combustion, the sensor calculates the quantity of air to fuel combination that is required. If it is clogged or defective, your car’s engine will produce excessive amounts of fuel.

Faulty manifold absolute pressure

You can’t run your engine without having one. It is responsible for transmitting information about the pressure within the intake manifold. It degrades with time, much like the majority of sensors. When it is malfunctioning, it sends inaccurate data to the ECU. This activity can have a number of negative repercussions, including decreased fuel efficiency and engine performance.

Engine coolant temperature sensors

When an engine is cold, it requires more gasoline to operate properly. The temperature of the engine coolant should be measured using the engine coolant temperature sensor. After that, it calculates how much gasoline should be put into the engine. If this is not functioning properly, your automobile will run rich due to the fact that gasoline is not controlled.

Fault in your fuel pressure regulator

In most cases, this problem has an impact on the combustion process and can cause the engine to lose its power.

If you want to determine whether or not the problem is with the fuel pressure regulator, your vehicle will exhibit the following symptoms.

  • Your engine misfires, resulting in a loss of acceleration. Leakage of fuel
  • Your exhaust pipe is emitting a thick black cloud of smoke. You’re leaking fuel from your exhaust pipe
  • Spark plugs that have been clogged with debris
  • Mileage decreases
  • The check engine light is illuminated. The scent of gasoline emanating from the oil dipstick
  • A problem with the intake temperature of your automobile

This post will answer any questions you may have about when you should replace your fuel – How long does gasoline have a shelf life? A banging sound may occasionally be heard coming from your car’s engine when this occurs. Alternatively, you may notice a decrease in your acceleration power. If the temperature sensor is broken, it should be replaced as soon as possible to avoid serious engine problems.

How to fix car running costly complications

It is simple to correct the fuel-air mixture. You have the option of getting to the root of the problem if you so desire. You must pay close attention to the performance of the devices listed below in your engine. Once you’ve identified the problem, you can take steps to correct it before your engine stalls.

Check your car’s air duct flap

The air duct in your automobile contains a flap that serves as a choke for your engine. As soon as you start your engine, you should see that the air duct is half open. It will only fully open up after the engine has reached operating temperature. It is necessary to send your vehicle to a mechanic if it does not execute these duties.

Vacuum hoses and lines

If your vacuum lines are not properly linked and your hose pipes are leaking, your automobile will operate at a high rate of efficiency. An audible hissing sound indicates the presence of a leak. In the event that you suspect a vacuum leak, keep an ear out for the hissing sound. It is possible that your engine sound will mute it.

Cleaning the mass airflow sensor

Dust is picked up by mass airflow sensors over time. When they get clogged with contaminants, they cause your automobile to run at a high rate of efficiency. Clean the sensor on your own, and then reinstall it after you’re through. It’s not difficult to clean it on your own either. You may always hire a professional to clean your home. If cleaning does not yield results, replacing the sensor with a new one may be necessary.

The oxygen sensor

If you have tested all of the devices listed above and they do not appear to be malfunctioning, the problem is most likely with your oxygen sensors. When a sensor becomes defective, it must be replaced with a new one. It is a delicate region, and you should usually leave it to a professional technician to repair or replace it.

Change your spark plugs

Spark plugs that have been worn out do not generate sparks. It indicates that the gas will not burn properly. As a result, your vehicle’s carbon dioxide emissions will be excessive, causing your engine to run rough. Changing your plugs may be the solution to your problem. If it does not, then you should take your car to a service center.


The most effective method of resolving a carrunning rich problem is to perform diagnostics anytime you believe it is occurring. Preventative maintenance, on the other hand, is the most cost-effective and efficient method. Regular maintenance and replacement of worn-out moving components are required for your vehicle. As a result, your vehicle is always in peak operating condition. When your automobile starts to run rich, it is not a reason for concern if the problem can be identified and corrected.

These are some of the issues that can be addressed once a successful diagnostic procedure has been completed.

It may be tough to keep track of all of these indicators. If this is the case, have your vehicle’s handbook with you at all times so you can learn more about your vehicle. Only replace the damaged parts in your vehicle’s engine that you are aware of in order to prevent future harm to the engine.

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