Pesky Idle surge. No boost leaks, new isc, new o2 sensor. what else?

[kidwiththelaser]

Ive got a pesky little idle surge problem. When its warm it idle surges between 1000-1500 rpm fairly rapidly. I put a new 02 sensor on it, and I tested for boost leaks. I found out that the intake manifold gasket was leaking and the TB gaskets were also leaking. Replaced all that and retested for boost leaks, found none and the bov was poping and it would stay pressurized for a while (30 sec to a min).

Then I borrowed a buddies palm with mmcd, and adjusted the tps to 10% and saw that the isc was reading about 27-33 when idling. I had a new one laying around so I threw that one on.

Also it has a hard time starting when cold. I thought it might need a new FIAV, so I threw a new TB on it. its STILL idle surging like crazy, oph and ive been adjusting the biss all the time to no avail.

Im thinking it might need a new temp sensor, but on mmcd it was reading very reasonable values.

What else could it be?



It was the ECU or the tb ground thingie!!!! Thanks for all your help.


thanks!

-Charlie

 

[kidwiththelaser]

Well now the car doesnt even want to start at all. So I took the CAS out and spun it over by hand and didnt hear the injectors ticking, so I tried 2 other CAS' I had laying around and still the same thing. I am buying a new ECU and going to throw that on when school gives me some free time.

I also picked up a TB with a FIAV blockoff. I'll throw that on if the new ecu doesnt help the idle surge.

 

[Andrew Conrady]

Good thinking about that ecu. I have read but don't know exactly why, but when the caps leak some they damage something in the board causing these idel problems. If repaired quickly sometimes you can still use your ecu. Again, not forsure but read this from a wiseman last week while browsing

 

[kidwiththelaser]

I had this problem after i cleaned my TB and i looked forever and you might want to go see if your car has this its a little ground that i forgot to put back in its on the bracket thats looks kinda like so ?

Remember i did it on paint . if you took off the long bolts holding on that bracket you might have forgot to put it back on it doesnt look like a ground its in a L shape (the ground) sorry if you cant tell what i did at all i tried.

thats also going off memory so bracket might look a little diffrent

Are you talking about that little "L" shaped thingie that is held onto the throttle body by a screw and the top throttle body bolt.

I know I dont have that on right now. I didnt know it was a ground. Ill go replace that and see what happens.

 

[MY1GDSM]

When was the last time you set your timing?
I seen you did a Blt But you also said you replaced the TB afterwords... do another just to be safe
and as everyone said FAIV may be the culprit I have a few that have gone to $hit
it would be a good idea to Take the cover off your Ecu and check the ISC drivers to make sure their not blown...

 

[kidwiththelaser]

Well I got a new ecu in there and reattached the little bracket that Alex_Brand was talking about and now she runs and drives great!

Thanks so much tuners!

 

[kidwiththelaser]

Anyone know how to edit the title so it was [RESOLVED] or whatever they put in there.