the car runs decently with a pcm4less tune but doesnt want to idle occasionally and doesnt drive very smooth at lower rpms. im thinking this will make it hard to pass the rolling smog test here in CA. mods in my sig + alt, starter, water pump, plugs & belt tensioner are new. I noticed a slight leak coming from the EGR connection to the pass side header, also the O2's havent been changed in a while but looked ok last removal. datamaster says both my left & right long term BLM's are high and that its running lean across the board. need to go pick up a fuel pressure tester just to be sure thats not an issue.

so could something mechanical like the exhaust leak, low fuel pressure, IAC motor, etc. be causing this, or do i just need a better/dyno tune?

note: that i asked pcm4less for a tune with passing smog being more important than max power

 

My suggestion is to check for all exhaust leaks prior to the 02's. After that, it could easily be just a refinement of the tune.

 

eww18:
Could be the IAC is dirty causing it to operate erratically. If you have an inconsistent idle rpm a dirty IAC is at least part of the problem.

 

A leak at the EGR tube connection on #8 runner can cause problems, but would show up as elevated BLM's primarily on the passenger side. 93's are the oddball, with both EGR and AIR connected at that point, so it may affect the system on both sides, although not likely.

How high are the BLM's, and in what cells? Its not running lean if the BLM's are still below 160, its able to correct the problem with the BLM's. Still need to find the source of the problem, but it depends how severe the problem is. When you say it "doesn't drive smooth", is it misfiring? Misfires will elevate the BLM's.

 

It will misfire once if you really step on it below about 3k rpm, but then it goes and pulls well. As for the dirty IAC, could I just shoot some carb cleaner in there to fix that?

Thanks for all the suggestions, I'm going to try and take it out today to get a longer datamaster log.

 

eww18:
I tried the carb cleaner but it only helped for a few weeks. I then pulled the TB and removed the IAC and cleaned it manually and heeded the warning not to push or pull on the pintle. That worked longer but after about 2 months it was back to idle anywhere from 800 to 1400 rpm also it would sometimes stick on closed throttle deceleration. Also as high as 1400 ... a real pain in heavy traffic on the interstate. Eventually I plugged the air supply hole to it and no longer care where it goes to. ISTR Freescan says it's at 160 counts all the time now. No ill effects, I easily pass inspection with very, very low numbers and the car decelerates as it should.

 

From experience, I recommend you change over to Open-Loop mode permanently. My 02 sensors never read correctly not matter what I tried, even heated 02's did not work. PCM4Less idle tuning was good, however because of the 02 issue, it never worked right. Once I switched it ignored them and idle improved dramatically. I verified my A/F on a dyno and it was spot on.

Switch to Open Loop and get some tuning on dyno. I gained over 70 RWHP on dyno over mail order tuning. Its a hit and miss.

Good Luck

 

Just to close out this thread, the IAC was stuck fully closed. Also had a melted #6 plug wire that was sparking to the oil dipstick causing occasional misfire. Fixed both issues and its idling great now.