04-09-2024, 03:40 PM
(This post was last modified: 04-09-2024, 03:42 PM by calciumdust.)
I did some driving around today with a scan tool running and recording.
Only code was a P300, misfires detected, which makes sense as it is misfiring at idle, it smooths out at higher rpms but is never perfect.
The STFT was -25% at idle, and apprached 0 during acceleration, which makes sense given the smog, no question that it is running very rich. Does the very low STFT demonstrate that the ECM is receiving proper data from engine sensors and determining that the fuel input need to be reduced? Therefore should I start testing injectors? (fuel pressure is all within' spec, FPR is functionign properly)
I'm seeing zero movement on LTFT, is that normal?
O2 sensor stayed around 0.9v, which makes sense given how rich it is running. I didn't get much movement on it either. It would periodically drop to near 0 volts and then back to 0.9v. It did not swing back and forth multiple times a second. Is that a symptom of a bad o2? The high o2 sensor voltage also makes me question my theory that the ex manifold leak is causing the engine to think it is leaner than it is. If that was the case wouldn't my o2 sensor have a much lower voltage?
If I pulled the front o2 and the car ran better would that indicate the o2 is failing?
Thank you for the advice! I'm still going to seek out a new ex. mani but I want to be sure that's my only problem.
Only code was a P300, misfires detected, which makes sense as it is misfiring at idle, it smooths out at higher rpms but is never perfect.
The STFT was -25% at idle, and apprached 0 during acceleration, which makes sense given the smog, no question that it is running very rich. Does the very low STFT demonstrate that the ECM is receiving proper data from engine sensors and determining that the fuel input need to be reduced? Therefore should I start testing injectors? (fuel pressure is all within' spec, FPR is functionign properly)
I'm seeing zero movement on LTFT, is that normal?
O2 sensor stayed around 0.9v, which makes sense given how rich it is running. I didn't get much movement on it either. It would periodically drop to near 0 volts and then back to 0.9v. It did not swing back and forth multiple times a second. Is that a symptom of a bad o2? The high o2 sensor voltage also makes me question my theory that the ex manifold leak is causing the engine to think it is leaner than it is. If that was the case wouldn't my o2 sensor have a much lower voltage?
If I pulled the front o2 and the car ran better would that indicate the o2 is failing?
Thank you for the advice! I'm still going to seek out a new ex. mani but I want to be sure that's my only problem.