Fuel trims. I think i know the answer but ..

[Sajk]

Hi all,

M52tu 2.8. M54 3.0 intake. CatCams 24lb VAC injectors. Tune from Active Autowerke.

Occasionally I get a non confirmed code for Bank 2 fuel trim exceeded buy never get an engine light. Today I decided to look at the trims when driving and accelerating.

SFT bank 2 is noticeably negative and under hard acceleration hits negative 19 which is huge.

It also suffers from an occasionally unstable idle where you can feel the occasional miss fire.

I suspect one of the injectors in bank 2 is dodgy OR the o2 sensor for bank 2 is bad but it does cycle quite well looking at the live data.

Ant thoughts and any suggestions on new 24lb injectors that don't cost 220 usd each like bmw ones.

 

[Sajk]

Bump. Nobody has any ideas?

 

[ChrisD]

Bump. Nobody has any ideas?

You could try to get your existing fuel injectors tested and cleaned/re-serviced.
If you’re running a retuned ECU, what warranty did it come with? Maybe speak to them.

 

[Sajk]

I am running a tune from Active Autowerke in the states. One bank being rich I don't think points to a tune issue? Not sure.

 

[Lee]

I would look at the lamba's and see what the voltages are and if they're reading ok. If they've never been replaced I would get a new set installed, alot cheaper than new injectors. Alternatively send your injectors away for cleaning and testing.

 

[Sajk]

I will look at the voltages again. I did check and they seem to be cycling between rich and lean on both banks at the same rate.