Idl surge Fixed (NOT) What else?

[95er97gsxtreme]

I am going to post this up, I know there are allot of Idle surge issues posted already but mine seems to be different I got a 95 GSX with minor mods. The most extensive engine mods are UICP, 1G BOV, LICP, MBC, Intake Pipe and K&N conical Filter.

History:
1 year ago got idle surge bad. Replaced the ICS with a used one. Ran fine. Then started acting up again two months ago. Bit the bullet and took it to the Mitsu dealer. They told me ICS. But wanted $400 to fix it. Sorry I've owned my GSX long enough to know how to change a ICS. Anyway I got a brand spankin New ICS. Put it in and my car idles at 750-800RPM.

Problem:
Now when I start it and drive all is well. But if I turn it off and get back into it then we have it surging to 1500rpms. If I hit the gas and bring it up to 4500 RPM quick it will then drop back to 750-800 RPM. Then it will start again. It seems to only happen if I've driven it for awhile and then turn it off and shortly hop back in it again. I would estimate the time to be about as long as it takes to fill the tank at the Gas station.

What I've Found:
when it is surging I have popped the hood and then inspect the Throttle cable. IT's not super tight and also not super loose. But I can actually put my thumb on the assy that the Throttle cable attaches to and push it closed. The idle then drops to 750-800RPM's and all seems well. But it will come back in a bit.

Questions:
What can it be?
Dirty throttle body, when it heats up there is some sludge or gunk in there that blocks the Butterfly? That is what I am assuming.
PVC valve going bad?

Any ideas would be greatly appreciated

Thanks

 

[1993eclipseGS]

Another cause of idle surge could be from a junk intake manifold gasket, The stock gasket is paper and can after time become garbage. That was my case when I bought my talon. But, It was to late to replace just the intake manifold gasket, I also hadto replace the head because of this little gasket caused big big problems for me. But anyways, That was the reason for my idle surge, Just an idea.
Rob.

 

[Coldandafraid]

you just stated yourself that the butterfly remains partially open, and you can close it by hand... that would be the reason for the higher idle right there... find out why it doesnt close all the way. Spring not tight enough, or lots of gunk on the inside...

 

[lovemydsm]

Are u venting to the atmosphere?

 

[doodie]

Try adjusting the slack of the throttle cable. If it reduces your throttle below 100% than I would just take off the whole TB and give it a good clean out. While your at it, you can try to whind the spring up another round so it will give the butterfly a little more pull when you let off the gas.

 

[95er97gsxtreme]

Nope not venting to the atmoshpere. I'll try all you have suggested and see what happens. As far as cleaning the TB what would you recommend. I know that the assy where the throttle cable hooks up has some plastic parts. Concerned if any cleaner would degrade the plastic. Once again thanks and I'll try this stuff and post the results.
Wish me Luck

 

[1993eclipseGS]

I used brake cleaner and it worked fine

 

[doodie]

Brake cleaner, throttle body cleaner, combustion chamber cleaner. Anything that will evaporate quick is fine. Also, while you have the Throttle body off, its a good idea to soak a towel up with some cleaner and use a pipe to clean out the inside of the intake manifold.

 

[nerfbars]

I have the exact same problem as you. I have changed the throttle body with a used one that had another set of sensors on it. I cleaned it before installing so there is no carbon. I have recently installed new plugs, wires, pcv, air filter, oxygen sensor, etc. I just ordered new throttle cables that is my next try. I hope its just a sticky cable. It sucks pulling up to a light and having your car idle at 3000k. Maybe I'll check the intake gasket by spraying some starting fluid at it while idling and seeing if that affects it. If it does than it may be sucking air there. Like yours I can also pop the hood and close the butterfly on the TB and get the idle down. I believe the only thing that holds the butterfly open is the cable or the spring not returing. I dont think its the spring b/c I tried a second TB. I'll have to look at my old TB and see it the spring can be wound tighter. Just thought I would let you know what I've tried and if I find the solution I'll let you know.

 

[jt1583]

i would use either brake cleaner or carb & choke cleaner, any auto store should have either but i would use the ladder of the two

 

[95er97gsxtreme]

nerfbars - please let me know what you find. I have been fighting this for quite some time and am wondering if something is screwed up in my ECU now. I took the TB partially off and the front side is clean as a whistle as well as the UICP. The back side of the butterfly has some stuff on it but ran out of time to finish it. So I just put it back together and don't seemed to be having the problem anymore. But I am not saying it is fixed. I am sure it will come back again. Please let me know what you find. Mine seemed to start when a friend came over and was looking at my enigine and TB. He said "hey your Throttle cable is really loose, I'll tighten it up." After that is when it seemed to start. I had him change it back but not sure what the deal was as it kept doing it. I took it to Mitsu and they said ICS. Replaced it and you know the story. I got a 1G TB that I think I might install when I get a chance. Keep me posted and I'll let you know how things go for me.

 

[nerfbars]

I have new cables on the way but I decided to put a little bit more slack in mine for now. It was fine on the way to work today but its so spuratic that it will take a few days to be sure. I'll keep you posted.

 

[gigahz95]

did you replace the gaskets...since you removed the throttle body?

Also, ironically enough, when i was scraping my old gaskets off my tb, the gasket remover arosol cleaned up the inside quite well, i opened the butterfly and cleaned all around the edges etc. (read the can, i think its mostly just mineral spirits and some other crap that makes it gummy)

 

[dsmer1]

i have had the same problem. did you do do a boost/vaccuum test? or smoke test? is sounds like a throttle cable to tight or a slight vacuum leak at the tb shaft seals/ o rings. i pust on my tb and it stops surging as well.

 

[Bud92gsx]

I had surge last year.This year got a tune, no more surge.I thought it was kinda strange, but hell it worked.

 

[Tiki2777]

FIAV Bypass fixed my problem and added more power due to there not being ####ing hot coolant heating my intake charge... There is a writeup on how to do the "free" way and it working amazingly!

 

[dsmer1]

FIAV Bypass fixed my problem and added more power due to there not being ####ing hot coolant heating my intake charge... There is a writeup on how to do the "free" way and it working amazingly!

+1 on the blocked FIAV. help my idle a whole lot. there are threads on here that show you how to block the FIAV for next to nothing without a plate. check that out

 

[tjohn23]

Don't block FIAV use bypass plate. It will be easier to control idle

 

[Calan]

did you do do a boost/vaccuum test? or smoke test?

Eh... do you realize that you are asking a question in a thread where the last post was over 8 years ago?

 

[autodsm]

Eh... do you realize that you are asking a question in a thread where the last post was over 8 years ago?

My question is how did he even find something this old and reply to it

 

[LiquidX]

Don't block FIAV use bypass plate. It will be easier to control idle

The bypass plate blocks the FIAV...

You are referring to the IAC which a block off plate removes as well. The FIAV is not part of the IAC.

 

[tjohn23]

Eh... do you realize that you are asking a question in a thread where the last post was over 8 years ago?

+1

First this thread is old and of no use to the orignal poster.

When I say FIAV block and bypass I'm referring to the type of plate not the actual FIAV.