M



more fuel trim readings. Just driving around town 40ish miles per hour.

 

There’s a couple more screen grabs. I don’t know if these readings are meaningful. I actually don’t know what to do with the fuel trim readings. I’m trying to monitor the readings for the next time. The sudden loss of power occurs. at the moment, I’m feeling ian overall loss of power so I kind of leading towards it being the catalytic converter. I have four hours to go until Colorado where they sell CARB catalytic converters, which is what my needs since I residie in California.

 

An easy test is to pull the front O2 sensor out of the exhaust completely. Does it now run better? (if a bit louder.....)

 

Those negative fuel trims are not a sign of bad cats, they are a sign of the engine running rich. So, either one or more fuel injectors are faulty, or perhaps the MAP sensor is no good.

 

Could also be due to incomplete combustion, if exhaust gases can't escape......

 

I finally managed to capture the fuel trims during one of the stalling events

for some reason, I keep having trouble uploading photos now. The forum upload utility stops at 90% on the first photo and does not continue.

trying to drive gently and give it lots of breaks. When it runs, it seems to run pretty good, and the stalling events just sort of appear out of nowhere. I am just an hour and a half away from Colorado where I’m going to pick up a new cat.

 

One of them says short term, 32 and long-term 6

another one says short term, 32, long-term, 32

 

For whatever reason, the PCM thinks the engine is running excessively lean..... bad O2 sensors??

 

You’re right. Simultaneously, during the stalling event, both O2 sensors were reading 0 V. The fact that both of the sensors were reading 0 V makes me think it’s not the sensors themselves but something else. Do you think maybe it would be the ECU? or maybe lack of fuel?

 

I believe the O2's get their sensor feed voltage directly from the PCM.... so yeah, that's a real possibility. Are any other sensors going to zero?? I would be curious about anything else that needs the 5 volt reference voltage..... Might check the connectors.... make sure they are clean, and tight.