Fuel trim codes back...

[Salty B.]

Originally Posted by Meestahbig

Ha. I'll take the over on Salty renting a lift before year end 2026!!!

I never put any additive into the car and I've owned and worked on it since 2006. Prev owner was in my family. Just so weird that both banks are reading the same bad values.

I got a lift appt for the 17th because I'm off the whole week for f'ing once, and a list of stuff to do besides all four O2s, so I hope you didn't place a big bet.

Peace bro.

[Fifty150hs]

I hate to say it but, plug your symptoms and other information into ChatGPT. I resisted, but finally broke down a few months ago. I've found it to be very helpful with troubleshooting problems.

[Meestahbig]

I've done everything chatgpt has told me. Since no error codes of faulty sensors, it has become a goose chance for me. I can't explain why both banks would read rich trim codes. At this point only thing I've not redone on the feul side are the injectors, but a pressure leak down test come back ok and both sides would be odd, except for the fact that all my injectors are the same age and wear. On the engine I've swapped everything with OEM, down to the throttle body gasket. I've not replaced the coolant temp sensor, but readings seem okay. I highly doubt it's the ECM, but I have no real clue. I can send it out for evaluation but I doubt its that. No Vanos errors so hard to suspect that, but could be. After swapping my O2 sensors I went over 3k miles no issue, no stalling or check engine light. All so very odd. Getting close to giving up. Two indy bmw specialist had no answer.

[Fifty150hs]

Originally Posted by Meestahbig

I've done everything chatgpt has told me. Since no error codes of faulty sensors, it has become a goose chance for me. I can't explain why both banks would read rich trim codes. At this point only thing I've not redone on the feul side are the injectors, but a pressure leak down test come back ok and both sides would be odd, except for the fact that all my injectors are the same age and wear. On the engine I've swapped everything with OEM, down to the throttle body gasket. I've not replaced the coolant temp sensor, but readings seem okay. I highly doubt it's the ECM, but I have no real clue. I can send it out for evaluation but I doubt its that. No Vanos errors so hard to suspect that, but could be. After swapping my O2 sensors I went over 3k miles no issue, no stalling or check engine light. All so very odd. Getting close to giving up. Two indy bmw specialist had no answer.

Bad MAF possibly?

[Meestahbig]

Nope, swapped the MAF with my other 3.0, the issue didn't move with the MAF.

[EODguy]

Live voltage readings?

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[Salty B.]

Prior to new pre-cat seonsors:

Short term fuel trim bank 1 sensor 1: 4.7
Short term fuel trim bank 1 sensor 2: 99.2
Short term fuel trim bank 2 sensor 1: 5.5
Short term fuel trim bank 2 sensor 2: 99.2
Long term fuel trim bank 1: –8.6
Long term fuel trim bank 2: –8.6

Today I pulled some readings with OBD Fusion. They don't seem to have changed much from before.

Short term fuel trim bank 1 sensor 1: 3.1 then jumping to 27.3, never negative
Short term fuel trim bank 1 sensor 2: 99.2
Short term fuel trim bank 2 sensor 1: 3.1 bouncing between –3.1 and +4/5
Short term fuel trim bank 2 sensor 2: 99.2

These readings did not change at all:
Long term fuel trim bank 1: –8.6
Long term fuel trim bank 2: –8.6

No codes, yet, but I've only driven about 20 miles since I replaced both pre-cat sensors. Replacing the post-cat ones next week.