Erratic Idle Revs.

[max6674]

I have a good one for you all here.

Was on the M way earlier today doing about 80-85 when some :censor: balloon with green L plates on her matchbox decided she liked the look of my lane better than hers, so she pulled out with no indication.

Slammed on as you do and got down to about 60 ish pretty quickly. Since doing this the car now ticks over at approx 2K and then will suddenly drop back down to 1K then shoots back up to 2K and so it goes on. Anyone got any ideas what could be causing this?

Cheers in advance.

[GT4 BOOSTER]

an ecu reset may help here ? worth a try

[daktari]

OK. Guessing really - but you might like to have a look in the engine bay and look for anything that may have become dislodged due to the high deceleration - Could`ve moved and pulled a vacuum hose off perhaps. Also might be worth looking in the AFM to see if the flap is sticking. Could be the fuel has surged in the tank and dislodged som gunk at the bottom of the tank, causing a partial block in the fuel system. Running out of guesses now..... Anyone..????

[max6674]

an ecu reset may help here ?  worth a try

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How do you do an ECU reset?

Cheers.

[daktari]

Remove the EFI fuse for a minute or two or you can disconnect the Battery but you`ll disrupt the radio settings and code if it`s a coded one.

It`ll probably run a bit rough for a mile or two when you reconnect. It has to relearn a few things.

[mikeb]

OK. Guessing really - but you might like to have a look in the engine bay and look for anything that may have become dislodged due to the high deceleration - Could`ve moved and pulled a vacuum hose off perhaps. Also might be worth looking in the AFM to see if the flap is sticking. Could be the fuel has surged in the tank and dislodged som gunk at the bottom of the tank, causing a partial block in the fuel system. Running out of guesses now..... Anyone..???? 

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N/A celicas don't have AFMs, so it can't be that.

If it really was related to the hard braking then the only thing I can think of is that a vacuum hose has split or popped off, or perhaps the brake servo has developed a leak somewhere. This would allow extra air into the engine, hence the raised idle speed.

The only other thing is the idle control valve or and ECU problem, but I don't see how they would be related to the braking incident. Anyway, unplug the ICV (nrear the throttle body) and if it is the culprit the revs will drop right down, and shoot up again when you plug it back in.

[daktari]

N/A celicas don't have AFMs, so it can't be that. 

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D`oh !!!!!! My bad.

[max6674]

Cheers for all the help. Its sorted itself out for some unknown reason, but I'm not arguing with it.

I will re-set the ECU also just to be on the same side.