I had my car tuned by PCM4Less, but since then I have put on Longtubes and I'm sure it's not perfect not even close, so if anyone would like to look @ it and tell me why my LTerms are @ 146 and my STerms are @ 164 I'd would appreciate it

Now I have little knowledge on tuning so far, but are the L/STerms suppose to be frozen @ 134/128 while in open loop waiting for the 02s?

Anyhow the log I got is from it idling in the garage about 15 minutes. It goes into Closed loop, then right back into open. But while in Closed loop the L/STerms rise from 134/128 to the numbers I mentioned above!

A noob question, 128 is stoich 14.7:1 A/F right? So the higher the L/STerm numbers, the leaner it is? And lower than 128 is rich, correct?

So if that's right, then my car is running LEAN in closed loop... any suggestions or willing people to look @ my log? I can provide it in .UNI or .CSV.

THANKS A MILLION!

 

Well post it up then! YES your car is running very lean! 164 is dumping way too much fuel!

Personally sounds to me like you got an exhaust leak! ESPECIALLY since you just put long tubes on! I would start there.

 

Isn't your car a 93?? Send me the log and I'll look at it later on tonight when I get home.

 

Which long terms (BLM's) are 146? Which Cells? Both sides?

In open loop, the PCM will only operate in 3 of the long term correction Cells, 16 (idle), 17 (over-run) and 18 (part load). It will use the stored BLM's from each of these Cells at the appropriate time. The BLM's will not change for any Cell, since in open loop, learning is diables. Your short terms should be as 128 (learning disabled) in all cases in open loop.

My immediate guess would be that the O2 sensors are not staying hot enough at idle to keep it in closed loop. Are you still using the 93's 1-wire (unheated) sensors with the long tubes? Appears that way.

"128" is a multiplier in the calculation of the injector pulse width. In effect, the term in the equation is (BLM / 128). So if your BLM is 128, you are multiplying the programmed fuel calculation by (128 / 128) = 1.00. If the O2 sensors see the the engine is running lean, they increase the BLM.... ex. (140 / 128) = 1.09375 means the PCM is having to increase the pulse widths by 9.375% to get the correct amount of fuel into the engine. In closed loop, at fully warmed up temps, the target A/F ratio is 14.7:1. The BLM will be raised or lowered, to the calculation produes a 14.7:1 A/F ratio (450mV on the O2 sensors).

No. Your engine WOULD be running lean IF the BLM's (long terms) were not correcting it. As long as the BLM's are within the limits of 108 - 160, AND the O2 sensors are accurate, the engine is running at 14.7:1.

If you can e-mail me a .csv version of the file, I will look at it. Be sure the subject line tells me what it is, because I generally delete attachments.