Need a little help with my idle problem

[Jslove1408]

So my idle is a little ghetto. Some times it idles perfect at 750 sometimes 600 sometimes 1000 and rarley it gets up to 1500 rpm. it is completley independent from the temperature of the engine it almost just has a mind of its own and decides what it feels like idleing at. I've checked the tps and for vaccum leaks any other ideas?

 

[Scott_S]

http://www.dsm.org/how-tos/tttt/tttt3.html
Try that and see if it helps at all

 

[Jslove1408]

Thanks ill go ahead and test it while im in the middle of doing so anyone else have some ideas?

 

[92 GSR-4]

yea,

Here's what I check in this situation, of course leak test it first!

1) throttle cable. Sometimes it's a little too tight and wont let the throttle shut all the way. It may need adjustment.

2) leaky bov can sometimes not show up on a boost leak test, but will actually open when the engine is at vac

3) baseline timing. must be at 5*

4)Baseline idle. Set baseline at 750

5) Check ISC. Test it with a multimeter. 2 coils inside go bad all the time

6) Bad fast idle air valve (FIAV) these can stick open causing air to bypass the throttle plate and cause a high idle.

7) inspect the TB itself. sometimes a "rocket scientist" has gotten in there with something and damaged the throttle plate itself making it not seal right inside the TB or not close all the way.

 

[SpoolinTalon2]

ya same problem here, im diling all messed up. i gotta try these things to get this fixed.

 

[Jslove1408]

which is the isc? right on the intake manifold or on the throttle body?

 

[92 GSR-4]

The ISC sits on the back of the Throttle body, on the same side as the battery,


Has a plug with 6 or 7 pins going to it. Grab a haynes manual or something and test it.

The FIAV is the one with the two coolant hoses going to it.

 

[92 GSR-4]

ya same problem here, im diling all messed up. i gotta try these things to get this fixed.

Good, I hope I can help you out. I just noticed both of you are 2G guys. The baseline timing thing won't apply, I think, since you do not have a cam angle sensor (CAS) like 1G's. I would still check out the timing with a timing light, just in case. Other than that, everything else should apply.

Good luck and let me know how you do!

 

[92 GSR-4]

oh, by the way. Please if this helps, please giv me some reputation points so I can post in the classifieds Thanks!

 

[Jslove1408]

I checked my base timing and everything lines up. and do you know by any chance how much resistance should be in the ISC?

 

[hiimt0ny]

Im having this idle problem also it goes to around 2,000 rpms its on a 92 gsx 6 bolt. i also have a vpc on it that the previous owner installed. just bought the car when it warms up the idle is fine. anyone have any ideas. when i try to adjust the vpc the idle doesnt change, it only changes when the engine warms up.

 

[84003TSI]

yea,

Here's what I check in this situation, of course leak test it first!

1) throttle cable. Sometimes it's a little too tight and wont let the throttle shut all the way. It may need adjustment.

2) leaky bov can sometimes not show up on a boost leak test, but will actually open when the engine is at vac

3) baseline timing. must be at 5*

4)Baseline idle. Set baseline at 750

5) Check ISC. Test it with a multimeter. 2 coils inside go bad all the time

6) Bad fast idle air valve (FIAV) these can stick open causing air to bypass the throttle plate and cause a high idle.

7) inspect the TB itself. sometimes a "rocket scientist" has gotten in there with something and damaged the throttle plate itself making it not seal right inside the TB or not close all the way.

Yeah #7, that's the problem I have right now. Thing sticks part way open and gets stuck real good. Haven't figured out how to fix it yet. Any suggestions?

 

[92 GSR-4]

Yeah #7, that's the problem I have right now. Thing sticks part way open and gets stuck real good. Haven't figured out how to fix it yet. Any suggestions?

Well hopefully they didnt damage the inside "bore" of the throttle body. If they did, its trash. If they just messed up the plate then you can replace JUST the plate buy taking the 2 screws out. If you are a 1G, you can find a NT throttle body and steal the plate. If the plate is ok and the bore is ok too, you may be able to loosen the screws up and adjust the plate until it closes perfectly, and then tighten them up. Normally when I rebuild a TB, I have to play with the plate a bit to get it to close right.

Hope this helps!,

Seth