LouF
Member
2005 GTP
Short description:
My long- and short-term fuel trims seems to be flat lining on one bank.
It hasn't saved DTCs for a long time.
Long description:
I have been trying to solve misfires for a long time. Many times I think I've got it, but soon after, the misfires return with no apparent consistency, what so ever.
I have recently noticed:
-My long- and short-term fuel trims seem to be flat lining only on bank #2.
-It does not store any DTCs anymore. Random misfire codes previously were logged - not for the longest time now, even when misfires do happen.
-My OBD2 code reader will continually reset if both LTFT and STFT for bank #2 are selected - but not if bank #1 is selected (no known issues to me with the device; I have not contacted AeroForce). I can see flatlining of both LTFT and STFT (bank #2) if the code reader has at least one other type parameter is selected (say, bank #1 STFT or LTFT), so that is how I see the static numbers.
-I no longer seem to notice a change in engine behavior if I unplug the MAF connector (I recall it previously did). I'm not 100% sure about open- and closed-
loop control status at these times, but it doesn't happen vary anymore.
Readings:
I run an OBD2 device (AeroForce Interceptor v2.8 firmware with 2-parameter display); this is how I am getting data (while parked or driving).
-Bank #1 STFT and LTFT are active and seem normal. (I do not have idle and 2,500 rpm ranges known at this moment.)
-Both up- and down-stream O2 sensor voltages seem to be between 0.1v and 0.9v and do not flatline.
-MAF reading seemed active (no good data to report at the moment).
(I am not experienced with much of this troubleshooting at this level, and I am overloaded with possibilities at this point.)
I have slowly replaced many things: ICM, upstream O2 sensor, spark plugs/wires, new exhaust, fuel injectors, acetone in fuel (to help clear catalytic converter blockage); high octane fuel, cheap gasoline, vacuum leaks, evap purge valve o-ring, MAF cleaning, thermostat, water pump. The fuel pump and crank sensor are original. I do not believe there is a head gasket leak (coolant level and oil look normal).
It runs OK, but I think it could be better, especially without the misfires acting up.
I get about 21-22 MPG (city mixed driving); 27 highway.
2005 GTP
139,000 miles.
Tweaking was done a long time ago where 3800 enthusiast richened some mixtures and made shifts longer drawn out and harder, as far as I can recall, as per my request/agreement. It ran as advised.
Short description:
My long- and short-term fuel trims seems to be flat lining on one bank.
It hasn't saved DTCs for a long time.
Long description:
I have been trying to solve misfires for a long time. Many times I think I've got it, but soon after, the misfires return with no apparent consistency, what so ever.
I have recently noticed:
-My long- and short-term fuel trims seem to be flat lining only on bank #2.
-It does not store any DTCs anymore. Random misfire codes previously were logged - not for the longest time now, even when misfires do happen.
-My OBD2 code reader will continually reset if both LTFT and STFT for bank #2 are selected - but not if bank #1 is selected (no known issues to me with the device; I have not contacted AeroForce). I can see flatlining of both LTFT and STFT (bank #2) if the code reader has at least one other type parameter is selected (say, bank #1 STFT or LTFT), so that is how I see the static numbers.
-I no longer seem to notice a change in engine behavior if I unplug the MAF connector (I recall it previously did). I'm not 100% sure about open- and closed-
loop control status at these times, but it doesn't happen vary anymore.
Readings:
I run an OBD2 device (AeroForce Interceptor v2.8 firmware with 2-parameter display); this is how I am getting data (while parked or driving).
-Bank #1 STFT and LTFT are active and seem normal. (I do not have idle and 2,500 rpm ranges known at this moment.)
-Both up- and down-stream O2 sensor voltages seem to be between 0.1v and 0.9v and do not flatline.
-MAF reading seemed active (no good data to report at the moment).
(I am not experienced with much of this troubleshooting at this level, and I am overloaded with possibilities at this point.)
I have slowly replaced many things: ICM, upstream O2 sensor, spark plugs/wires, new exhaust, fuel injectors, acetone in fuel (to help clear catalytic converter blockage); high octane fuel, cheap gasoline, vacuum leaks, evap purge valve o-ring, MAF cleaning, thermostat, water pump. The fuel pump and crank sensor are original. I do not believe there is a head gasket leak (coolant level and oil look normal).
It runs OK, but I think it could be better, especially without the misfires acting up.
I get about 21-22 MPG (city mixed driving); 27 highway.
2005 GTP
139,000 miles.
Tweaking was done a long time ago where 3800 enthusiast richened some mixtures and made shifts longer drawn out and harder, as far as I can recall, as per my request/agreement. It ran as advised.