Idle problem driving me nuts, check out my PL log file please

neat

Member
I can't seem to get this idle problem straightened out on my Regal. It's an 87 with some light mods.

I had been driving for about an hour, and I stopped to get gas. I filled up, and took off. 2 blocks after filling up the car developed a stumble at idle. It would bounce around, not want to settle down, and stumble with anything less than about 10% throttle.

I have no check engine light.

I checked it with power logger and don't see anything odd, but I'm really new with the PL, so maybe someone else will see something.

I checked for the obvious stuff, no vacuum leaks, the plugs look great, all cylinders are firing, and I didn't find any disconnected sensors or anything.

Coil pack was swapped with a known good one, no change.

I'm running a turbo tweak chip, which has an open loop idle.

The IAC counts seem normal, about 30, and then it will rocket up to 130+ when the engine tries to stall.

The IAC is new, about 4 months old.

I replaced the EGR valve today with no change. I also replaced the O2 with no change.

MAF passes a tap test, and the car runs worse with the MAF unplugged.

Chip/socket is good, unless the chip has somehow failed internally.

Fuel pressure is good, even during the stumble, about 42 PSI at idle with the vacuum line connected.

The other day I built and installed an EGR block off plate which seemed to help the car. Figuring I had found the problem, I replaced the EGR valve with a new one. After installing the new EGR valve, the problem seems to be just as bad as it was, negating the positive improvement from the block off plate. However, I've been stressing over this for awhile now, so the improvement from the plate, and associated return to poor performance, could all be in my head.

The log file is the car idling and surging. I'm not sure how to post it, it's a .dat file so it's not allowed to be uploaded. I can change the extension to .txt or something, but then it's also to large. Shoot me your E-mail address if you want to see the log and I'll send it to you. joshkinzey@gmail.com is me.

Thanks for the help.
 
Did you mean fuel pressure was 42 psi with the vacuum hose off? If it's 42 with the hose on that's seems high.
 
Try removing the IAC and cleaning out the area where it screws in. Use cotton swabs and carb cleaner. Keeping swabbing it out until the qtips are clean. Do not mess with the IAC. It is very delicate. A dirty IAC inlet can cause idle problems.
 
It does it all the time, regardless of temperature.

I'll try cleaning the IAC port tonight.

I don't remember if I was line off or on with the fuel pressure, I'll check it again tonight.
 
Turns out one of the screens had partially fallen out of the MAF sensor. I'm not exactly sure why, but that was my problem. I fixed the screen, and all is well.
 
The log file is the car idling and surging. I'm not sure how to post it, it's a .dat file so it's not allowed to be uploaded. I can change the extension to .txt or something, but then it's also to large.

For future reference you need to right click on your logged ".dat" file the click "send to" compressed (zipped) folder. Then save that zipped file somewhere.

You can now upload that zipped .dat file to this forum. You may want to try it here just for practice.
 
up-load a zip powerlogger .dat file

For future reference you need to right click on your logged ".dat" file the click "send to" compressed (zipped) folder. Then save that zipped file somewhere.

You can now upload that zipped .dat file to this forum. You may want to try it here just for practice.

Well.....we will TRY to upload a zip .DAT powerlogger file.
We have been having a problem with knock----- .7 deg of knock at 27psi boost. We have a little "blip" were our WBo2 will rise(this were we get knock) then it will settle down to 10.8-11.3 on the WBo2.
 

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