I'm getting alot of surging on a cold start, it does get better as the car gets warm. The surging does seem to follow the WB O2 guage bouncing between rich/lean. I did an IAC adjustment and it helped but its not
perfect. It doesnt go totally lean like it did this past fall when I had a vacuum leak between the intake and heads. I put the car on a smoke machine and
showed no more vacuum leaks. It has a new 02 sensor,new coolent
temp,TPS sensor, new plugs,wires,distributor. i'm not getting a code
but i'm wondering about my MAF sensor being bad?? The car stays between
14.5 and 15.3 driving normal, it'd just funking at idle in park or
neutral, it will momentarily spike lean to the high 17's before returning to mid 14s-low 15s...Any ideas???

 

I think your WB reading is showing the result of the issue, not the issue.

As you know vacuum leaks are number one cause of surging up and down idle. It's just trying to fix the problem. I would again, check for vacuum leaks, PCV valve, brake booster etc... if known can be found have you done the Min Air and IAV reset? HTH!

 

I put the car on a smoke machine, no vacuum leaks

 

I've never used one but have heard of them. You seem confident in it, will it for sure tell if a vacuum brake booster is leaking and PCV valve is not overleaking etc... just trying to help.

I have done a lot of conversions and helped a lot of people with their EFI cars and only a couple times could a surging idle not be cured by finding the vacuum leak. Both of these were MAP systems and both had larger than stock cams and both were chip burned to open loop idle and tuned the fuel to a perfect smooth idle.

 

I hooked the smoke machine up from the PCV line and it filled the Fuel injection system up with smoke. The only place came out of was the air filter. It does indeed surge like a vacuum leak.

 

Log seems to show some surging up and down. BLM/INT are close to 128. It may be a cam issue with abit of overlap. I have been tuning a car with that cam on a heads/cam L98 and it idles very nicely at around 800 rpm or so. Wideband reads very lean and I dont think the BLM/INT show 128 either but its happy there and car drives just fine with BLM near 128 and 14-15 to 1 air fuel while cruising.

You can try tweak the timing abit more, try different plug gaps, try tweaking the MAF tables ever so slightly. Maybe lean it out a touch more? Do the plugs look tan at idle? Go for more tan/light grayish color and see what happens. It may help smooth idle out.

Try more or less timing. It may want less timing and stabilize out at a lower rpm. I run alot of timing at idle for my buddy's car. i think its 28-29 deg now and it likes it. Havent had a chance to look at his car in a while tho.

Have you tried open loop only tune? See if it does any better.

 

thanks Orr