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

 

[92_eclipse_GS]

im not very knowledgeable myself but id would deffinately recommend checking out "clubdstaDOTnet" and ask redleader36, he is very knowledgable and the owner of the site.
he has helped me fix countless problems like this and has never failed to know the answer.
good luck

 

[kidwiththelaser]

oh, i forgot to mention that egr valve is blocked off and so are the emissions vacuum lines on the TB.

 

[Rob10_99]

If it has not boost/vac leaks, what does the TPS read now?
Check the voltage coming out of it with the throttle closed all the way.

 

[kidwiththelaser]

If it has not boost/vac leaks, what does the TPS read now?
Check the voltage coming out of it with the throttle closed all the way.

This damned palm pilot keeps resetting itself and deleting mmcd. Finding a laptop with a serial port is getting harder and harder to do, but as soon as I get mmcd up and running again ill grab some logs and post em up.

Thanks!

 

[TurboTerror99]

Both of my 1gen cars have had an annoying idle surge. I never did find the prob on the first one but my second one need a new MAF. Apparently, there is some kind of wax pellet in it that overtime breaks down and should be acting like a check-ball. If you have a new one throw it on and see if it makes a difference. Good luck!

 

[cummins990]

I fixed mine by adjusting the TPS

 

[1gDSMike]

what throttle body do you have?
I had this surge after cleaning my throttle body, it was the idle position switch (1g tb).

 

[kidwiththelaser]

Ive got a 1g TB. I just got mmcd to work again and adjusted the TPS back to 10%. Still surging like crazy.

-Tried disconnecting the idle switch and it wouldnt surge but would idle over 2000 rpms.
-Tried disconnecting the Maf sensor and it still idle surged the same, but sounded a bit different.
-Checked the throttle cable and its nice and loose.

Also I drove it around the block real quick and everytime I left off the throttle it would hold the rpms for a second before dropping down.

Ill post my mmcd logs in a second, they are transferring onto my computer.

 

[nyTalonTsi]

Im having the same problem, once my car warms up idle surge is annoying. I think my Biss is leaking its all stripped out, plus i killed another isc.

Im planning on replacing the biss and o-ring. Have you replaced the biss o-ring?

 

[Boost_Addict_88]

Have you replaced the biss o-ring?

+1. Might as well replace tha BISS itself as well. You can get both for under $5 at tha dealer. Also, check tha idle control motor.

 

[1gDSMike]

Are you still using the 2g tps? If so you dont need to have the idle switch plugged in but you still can use it for an idle stop, when i cleaned my tb it opened it up so much more that my idle switch was holding it open to far and the isc was fighting it . Make sure the idle switch isnt screwed in too far and thats its adjusted right.

 

[solidviper89]

I had leaks post maf, that were making me stall.

 

[kidwiththelaser]

Wow, I just went a re-read through my post. I cant believe I forgot to mention that this was on a 1991 GVR4!

Not a 95 GST!!!

Can I use a 2g TPS on a gvr4? Ive got a few laying around.

Also my log file seems to be corrupted or something, because it didnt want to upload all the way onto the computer.

 

[yokotabrat]

Are you sure the throttle body you tried has a known good FIAV?

It could also be the ecu. If you have another you could swap in from a known good car, that might help isolate it. Another test would be to reset the ecu, pull the isc from the throttle body but leave it connected to the harness and while someone turns the key to ON (not start) see if the isc pintle moves at all. If not, either the isc is still bad, or one or more drivers in the ecu are bad.

 

[kidwiththelaser]

Are you sure the throttle body you tried has a known good FIAV?

It could also be the ecu. If you have another you could swap in from a known good car, that might help isolate it. Another test would be to reset the ecu, pull the isc from the throttle body but leave it connected to the harness and while someone turns the key to ON (not start) see if the isc pintle moves at all. If not, either the isc is still bad, or one or more drivers in the ecu are bad.

Thanks for the reply. I dont know for sure that the FIAV is good but I tried 2 different throttle bodies.

If mmcd is showing reasonable values for the isc, could it still not be functioning properly?

 

[1992GSX]

I had the same problem with mine. I tried two different throttle bodies and both happened to be bad. I dealt with it until I decided to block off off my FIAV completely. When I did that, I also replaced the ecu at the same time and the problem was fixed. Out of curiousity, I threw in the old FIAV to see if the problem came back without the block off and new ecu, and it did. I just wanted to see which one was what, and it was the FIAV.

 

[yokotabrat]

Thanks for the reply. I dont know for sure that the FIAV is good but I tried 2 different throttle bodies.

If mmcd is showing reasonable values for the isc, could it still not be functioning properly?

No problem. No, the values reported for the isc from a logger are just what the ecu thinks it's doing. It has no feedback on its actual position.

 

[kidwiththelaser]

No problem. No, the values reported for the isc from a logger are just what the ecu thinks it's doing. It has no feedback on its actual position.

But if it has reasonable values the ecu is controlling it properly right? Meaning the isc drivers on the ecu aren't bad.

Or am I wrong?

Ill see if I cant find a known good throttle body, and throw that on.

 

[Spoolin4Ever]

FIAV

Remove and block it.

 

[KiNg MaRtY]

I am having a similar problem with my GVR4. It comes on an off a day here and there for an hour or so. RPMs climb to 3k and then begins to idle surge. Once I hit the throttle it will stay at 3k again. It hasn't gone away today. My fiav and egr are both blocked off and I have dsmlink. They told me the ecu was good. New o2 aswell

 

[Spoolin4Ever]

I am having a similar problem with my GVR4. It comes on an off a day here and there for an hour or so. RPMs climb to 3k and then begins to idle surge. It hasn't gone away today. My fiav and egr are both blocked offand I have dsmlink. They told me the ecu was good

That still leaves the ISC Is that blocked or not? I have FIAV and ISC both blocked after this last episode was driving me insane! I was driving with an idle that would bounce from 550rpm-2000 .


I took the ISC out of the picture just in case, because I was getting tired of testing over and over, sometimes a bad part can test good too, like an ISC, that's why I pulled and blocked it.

 

[Spoolin4Ever]

Ive got a 1g TB. I just got mmcd to work again and adjusted the TPS back to 10%. Still surging like crazy.

-Tried disconnecting the idle switch and it wouldnt surge but would idle over 2000 rpms.
-Tried disconnecting the Maf sensor and it still idle surged the same, but sounded a bit different.
-Checked the throttle cable and its nice and loose.

Also I drove it around the block real quick and everytime I left off the throttle it would hold the rpms for a second before dropping down.

Ill post my mmcd logs in a second, they are transferring onto my computer.

FIAV

 

[Alex Bland]

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

 

[Spoolin4Ever]

Im having the same problem, once my car warms up idle surge is annoying. I think my Biss is leaking its all stripped out, plus i killed another isc.

Im planning on replacing the biss and o-ring. Have you replaced the biss o-ring?

If it acts normal until it warms up, I suspect the FIAV for that as well, because it is was is in charge of changing the idle speed from cold to warm. On my car, that was also the case, when it was warmed up it would constantly bounce from about 500rpm-2000rpm.

At first it didn't do it all the time, it was kinda intermittent, but then it did it all the time.

But I am speaking of a 1G. I do not know, can you pull and block the FIAV seperatly on a 2g?