High Idle, tried everything.

[b-morr]

I'm at a loss of what to do. My car idled around 2000RPMS, and I traced a vacuum leak to around the intake mani gasket. When I pulled the intake mani I noticed it was broke. One of the tabs where the bolt go in was broken off. I put a new intake mani, replaced all gaskets an sealed with cooper spray. Car idles at 2000 still.. Now vacuum leaks, biss oring good, and screwed in all the way. ISC good, throttle body has been rebuilt. And I'm lost..

No surge just high idle.

 

[mesarius]

Have you checked the tension of your throttle cable? It could have slipped holding the butterfly valve open.

 

[hdoerr]

A logger would tell you the throttle pos.

 

[b-morr]

I guess I should have added that, but yeah, thats the first thing I checked.

 

[doggo]

A logger would tell you the throttle pos.

high idle means more air is getting in the intake mani than there should be. Either you have a vacuum leak on the intake side of the motor, the throttle cable is loose or BISS or ISC is set wrong.

1st check the throttle cable,
if no change...
2nd try to set base idle by grounding ISC via the ground plug on the motor firewall.
if no change...
3rd do a boost leak test, check for leaks

 

[b-morr]

high idle means more air is getting in the intake mani than there should be. Either you have a vacuum leak on the intake side of the motor, the throttle cable is loose or BISS or ISC is set wrong.

1st check the throttle cable,
if no change...
2nd try to set base idle by grounding ISC via the ground plug on the motor firewall.
if no change...
3rd do a boost leak test, check for leaks

done.
done.
done.

Thats why I'm lost...

 

[snowborder714]

biss oring good, and screwed in all the way

The BISS shouldn't be all the way in. To set it, you should screw it all the way in and then back it out 3 1/4 to 3 1/2 turns, or until you can get it to idle around 750 RPM's.

 

[b-morr]

The thing is, I cant get it to idle that low, even when I ground the plugs to set the idle properly. I figured it would be a vacuum leak, but I tested it as well as sprayed carb cleaner around, but no idle change.

 

[Artago]

fiav or egr????

 

[b-morr]

egr is blocked. Actually never thought about fiav, how would I check that, or am I able?

 

[Artago]

egr is blocked. Actually never thought about fiav, how would I check that, or am I able?

I don't really know of a way to check it.

Here's a good link.
Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

Replace the seal or bypass it. I'm bypassing mine next time I take my TB apart.

I got my bypass plate here: Level Zero Motorsports

Along with my COP plate, and EGR plate. Gave me FIAV seals too. Great deal.

Tom

 

[b-morr]

I should have had it blocked when I got it rebuilt.. but now that I think about it, when it was rebuilt all the seals were replaced. So I'm guessing that has already been done. That was about 100-200 miles ago.

 

[8urv8]

I'm betting on a bad fiav.

 

[quick_dsm]

any luckk???

 

[dsmfreak1984]

had a similar problem with my 95 gst when I first bought it, turned out the throttle cable was sticking, a generous amount of WD-40 fixed er right up, just an idea.