Ok so new wideband A/F gauge is in. I am puzzled. I am reading anywhere from15.0 to 17.5 ish at idle, BUT the BLMs are 108 at idle...it is the same at higher rpms, the a/f reads very lean bu the l trims are low, 108-110 and S trims are high...136-150 and it backfires like a basterd. and adjusting the VE tables at the map and rpm are not helping...where to start.

 

anyone

 

I had a similar issue on an old motor, it was burning oil, which was making it look like things were really rich to the O2's/computer, which then was pulling all the fuel it could causing a lean condition.

What do your plugs look like? Is there any smoke coming from the exhaust?

 

no, no smoke, I had a split blm issue but fixed that after a small exhaust leak and drilling the iac passage alittle more. ed with fastchips advised me that the part throttle wideband readings, while more accurate than narrow band is still not a reliable tuning tool because of the rapid fluctuations the computer is doing and the fact that it is an averave, the WOT it is the only way to go. Im mainly puzzled by the difference in short and long term fuel trims at the moment....

 

Sort of hard to make any in-depth analysis with the limited data you've posted. Why not make the entire data log available?

 

Where is your wide band O2 sensor? Could you have and exhaust leak between your pcm's O2's and your widband O2? Are your blm's and trims about the same left to right?

 

Thanks for the replys, what is the best site for hosting data like our logs? Oh and I have looked for leaks at nausium if anyone has a highspeed way of finding leaks i would gladly try it, instead of the "burnt hand" method....