Urgent: 4age idling at 4000 after 2 hour drive

[Jusdrifn 86]

Hey guys, have a really quick question about my AE82 twincam daily.

Went down the coast last night and coming home as I exited th 100km zone, the idle was stuck at 4000rpm..

(It sits on 4000rpm on the highway, so I would not have noticed it if it happened a bit earlier)

Earlier that morning in an attempt to clear an oil leak defect the engine bay recieved a fair bit of degreaser and water cleaning.. but had been driving completely normal for around 3 hours before the problem was noticed.

What I have checked:
-The butterfly does not appear to be getting stuck, and is closing fully
-The car has full water/oil/fuel ect, and was not overheating at the time
-The problem was still there this morning when I started the car (thought after a night of cooling down it might have gone away)
-Unpluging the TPS did not change anything
-All the belts are still on (aircon, alternater ect)
- Idle screw is still wound mostly down, and putting fingers over coldstart and idle holes doesnt slow the idle back to normal, dropped it by about 100rpm to 3900
-From what I can tell all vacuum lines and electric plugs are still connected and there are no vacuum leaks (I removed a vacuum line and it idled really badly at 2500rpm)
-No dash warning lights
-No signs of anything leaking or blowing smoke while driving.
-Nothing else electric seemed to be effected... :S

If anyone can give a suggestion of what I can look into fixing today before traffic tomorrow it would be much appreciated, I have a whole spare 4age at my parents so I can swap most easy parts...

Thanks in advance
Justin
0410101090

(and if anyone is bored and wants to help in Clayfield, Brisbane, be my guest, there is beer)

[dr1ft-pig]

try disconnect the battery for a while and let the ecu reset itself....

maybe try swapping the throttle body also...

[Golberg]

To get idle up that high you MUST have an air leak somewhere.

Check around your intake manifold where it bolts to the head, check your TVIS plate, check your injector holes. Check anywhere where air could possibly get in.

Your brake booster could also have shat itself.

Try putting your hand entirely over the throttle body and see if the car stalls too.

[Jusdrifn 86]

Ok guys, problem solved,

thanks for your help, turns out I just didnt see the problem at 1am on the side of the highway with my keyring led light.

there are 2 bolts that can hold the throttle open, i only saw the bigger bottom one which was not touching, so I thought that it was not that, but It was the thinner allen key one that had lost its bolt, and during the 1 hour highway drive, it had rattled up against the throttle and held it up against where the throttle was positioned at 4000pm/100km/h

Silly me... thought I saw everything last night but I didnt..


Now to hide a front main seal leak while a mechanic signs my defect.. anyone know how to do that?

Enjoy your Sunday boys...