I have p0172/0175 codes on my GMC 4.3L. MAF shows 9-10g/s with negative -20 fuel trims. Codes are for banks 1 and 2 rich. Not sure what else can cause it
Rich are caused by Fuel related issues as well. Check your Fuel Pump Pressure. Check the Upper Oxygen Sensors. Or you can first just disconnect the MAF, and monitor the FUEL TRIMS. If they go normal between +10/-10, then its a bad MAF.
@@MyAutoproblems I replaced the MAF and didn’t change the readings. Still 8-9g/s. Upstream Oxygen sensors are fluctuating between .1-.8v like normal. Downstream appears to be a Little Rock .6v. What can cause the MAF to read high? It’s a 4.3L. The MAF should be reading close to that
@@SubePelayo928 IAT or dual IAT Barometric Sensor in the intake plenum somewhere? Is barometric pressure locked at a low default like 16.095 etc? Or fuel pressure regulator is letting too much pressure through and pulse width cannot adjust ? Or air intake restriction before the maf such as air filter dirty or IAT and MAF itself is dirty, oily, contaminated by other cleaner than maf cleaner? Ever solve this?
I drive a 2015 GMC Sierra 1500 5.3 4 wheel drive,my ? Is that my ltft bank 1 is -15 an my stft bank 1 is 3).an ltft bank 2 is -19 an my stft bank 2 is 2 so my question is this a Rich condition or a Lean condition I like your videos keep them rolling thank you please respond
Ideal values of ltft should be between +10 to -10. If the values is in Plus, its a lean condition. If the value is -negative, then its a Rich condition. If your vehicle comes with HIGH pressure Fuel Pump, then it might be bad. Check the Engine oil level, its viscosity and smell for Gasoline mixing because of a failed Pump.
5.3 GMC Fuel consumption Hard shifts Rough running Rough idle Shudders under acceleration/loss of power/boggish Feels like misfiring but no misfires detected Sparked plugs (twice in a month) ac delco oem Spark plug Wires ac delco oem Coil packs MSD Replaced alternator Changed oil and filter multiple times Trans fluid at perfect levels, still red, smells ok Removed and cleaned MAF sensor Removed and cleaned throttle body Replaced all 8 fuel injectors (took it to a shop for that) New a/c compressor and pulley (failed causing overheating at idle) new one fixed that. Replaced Barro sensor or “MAP” sensor After all that the truck runs better, but is still having all the stated issues at TOP. I balanced the fuel Injectors and I am inexperienced but they seem just slightly off to me. I also have only once intermittently witnessed live data short term fuel trims at -100. Not sure what would or could have caused that. Looking for any advice this video was helpful thank you very much going to try this and check FP before bringing back to shop that put in the injectors. Thank you!
Only codes I have are BCM codes from broken headlight lens, license plate lamps, and tpsm out. ECM Invalid Data from BCM-invalid data- U0422-71 2 other codes in history that aren’t current.
@@MyAutoproblems the history codes were for an abs brake line that was damaged and fixed and for a BARO sensor that according to the scanner, looks like it was only thrown once in the past at some point. I changed it with a new one to be sure, and when I saw it though for sure that was my issue. But no luck after replacing it. I will get live data fuel trims tomorrow. Thank you so much for the insight.
Short term fuel trim bank 1 bounces between 0 and 2 Long term fuel trim bank 1 stays at -6 Short term fuel trim bank 2 bounces between -1 and -2 Long term fuel trim bank 2 stays at -7
I have p0172/0175 codes on my GMC 4.3L.
MAF shows 9-10g/s with negative -20 fuel trims. Codes are for banks 1 and 2 rich. Not sure what else can cause it
Rich are caused by Fuel related issues as well. Check your Fuel Pump Pressure. Check the Upper Oxygen Sensors.
Or you can first just disconnect the MAF, and monitor the FUEL TRIMS. If they go normal between +10/-10, then its a bad MAF.
@@MyAutoproblems I replaced the MAF and didn’t change the readings. Still 8-9g/s. Upstream Oxygen sensors are fluctuating between .1-.8v like normal. Downstream appears to be a Little Rock .6v. What can cause the MAF to read high? It’s a 4.3L. The MAF should be reading close to that
@@SubePelayo928 check the Fuel Pressure.
@@SubePelayo928 IAT or dual IAT Barometric Sensor in the intake plenum somewhere? Is barometric pressure locked at a low default like 16.095 etc?
Or fuel pressure regulator is letting too much pressure through and pulse width cannot adjust ? Or air intake restriction before the maf such as air filter dirty or IAT and MAF itself is dirty, oily, contaminated by other cleaner than maf cleaner? Ever solve this?
Figured out the problem, it had a leaking regulator and a bad EVAP solenoid on the intake
I drive a 2015 GMC Sierra 1500 5.3 4 wheel drive,my ? Is that my ltft bank 1 is -15 an my stft bank 1 is 3).an ltft bank 2 is -19 an my stft bank 2 is 2 so my question is this a Rich condition or a Lean condition I like your videos keep them rolling thank you please respond
Ideal values of ltft should be between +10 to -10. If the values is in Plus, its a lean condition. If the value is -negative, then its a Rich condition.
If your vehicle comes with HIGH pressure Fuel Pump, then it might be bad. Check the Engine oil level, its viscosity and smell for Gasoline mixing because of a failed Pump.
Yes but which one do I look at the stft or the ltft which one is telling me that it has a lean condition so I look at stft
5.3 GMC
Fuel consumption
Hard shifts
Rough running
Rough idle
Shudders under acceleration/loss of power/boggish
Feels like misfiring but no misfires detected
Sparked plugs (twice in a month) ac delco oem
Spark plug Wires ac delco oem
Coil packs MSD
Replaced alternator
Changed oil and filter multiple times
Trans fluid at perfect levels, still red, smells ok
Removed and cleaned MAF sensor
Removed and cleaned throttle body
Replaced all 8 fuel injectors (took it to a shop for that)
New a/c compressor and pulley (failed causing overheating at idle) new one fixed that.
Replaced Barro sensor or “MAP” sensor
After all that the truck runs better, but is still having all the stated issues at TOP. I balanced the fuel Injectors and I am inexperienced but they seem just slightly off to me.
I also have only once intermittently witnessed live data short term fuel trims at -100. Not sure what would or could have caused that. Looking for any advice this video was helpful thank you very much going to try this and check FP before bringing back to shop that put in the injectors. Thank you!
Only codes I have are BCM codes from broken headlight lens, license plate lamps, and tpsm out.
ECM
Invalid Data from BCM-invalid data- U0422-71
2 other codes in history that aren’t current.
What are the history codes? And can you monitor the fuel trims at vehicle Idle and provide me with that.
@@MyAutoproblems the history codes were for an abs brake line that was damaged and fixed and for a BARO sensor that according to the scanner, looks like it was only thrown once in the past at some point. I changed it with a new one to be sure, and when I saw it though for sure that was my issue. But no luck after replacing it. I will get live data fuel trims tomorrow. Thank you so much for the insight.
Short term fuel trim bank 1 bounces between 0 and 2
Long term fuel trim bank 1 stays at -6
Short term fuel trim bank 2 bounces between -1 and -2
Long term fuel trim bank 2 stays at -7
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