[Corsa B 1993-2000] high idle speed on v reg corsa 1.0

[mikeW]

Hi all, new to site and not much of a mechanic.
Car been running rough for a while; erratic idle loss of power on hills.
have cleaned throttle body, ICV and MAF. also blew out all pipes which where completely gunked up.
Since then idle speed is very high, today my partner(who drives it), said it seemed worse when she braked???
AT a complete loss as what it could be. Any help would be greatly appreciated
Many thanks

[Taurus]

Possibly a brake servo problem. If air is leaking through the vacuum pipe it will make the engine run lean which will cause loss of power. An air leak will also cause idle issues since the ICV is effectively being bypassed.

The brake servo vacuum pipe clips into the back of the inlet manifold - there is a fiddly yellow clip. If you can temporarily disconnect it, block the inlet stub and see how that affect the engine. Be advised that you of course have no brake servo so don't try driving the car. Check the pipe itself for damage, or the leak may be inside the servo.

[mikeW]

Thanks for feed back Taurus, checked brake servo, all seems ok.
Ran the engine this morning, idles ok at first, as engine warms the idle increases, if accellerator depressed and released it takes time for revs to come down.
Although I cleaned MAF is is possible this is shot and causing problem?
As far as power loss concerned, car going up a certain hill in 3rd now whereas it struggled to get up in 2nd before

[Michael]

Just a thought on the idling, but, when I had my 12v Corsa, the previous owner had adjusted the throttle body positioning thingy. Made it rev higher and rev itself. Got it adjusted back to stock and the car was fine

[mikeW]

Hi Michael, that thought had crossed my mind, could be that where my partner bought car had done this(but that was over 3 years ago), I think this is the first time things have been cleaned up since she bought it, so a possibility

[mikeW]

Hi guys,
Still not sorted this. installed new MAF,(i'd ordered it), checked and rechecked for vacuum leaks, but still a problem.
Start it from cold it idles fine, once warmed the revs just start to rise, the EGR appears to be blanked off,(no metal pipe coming out).
Could it be as Michael stated the idle stop screw has been previously adjusted, or could it possibly be air lock/blockage in cooling system.
help please

[Taurus]

The EGR blanking on those consists of replacing the gasket between the EGR and the head. The metal pipe running to the inlet can be left in place. If it's been removed make sure that the port on the inlet manifold where the pipe connects to has been sealed. It's right underneath so you can't see it without getting underneath the car and looking up at the back of the engine. If that isn't sealed and the pipe is missing you'll have an air leak into the intake. That will throw the idle and cause it to run lean which will account for power loss.

Without seeing it it is impossible to say if someone has mucked about with the throttle body. You'd need to compare it with a know good 'un.

The MAFs on these don't usually like being cleaned, though it sometimes works. If you've bought a replacement is it a genuine Bosch one? Some (most) of the aftermarket ones are rubbish.

[jorded94]

Whats it idleing at? I had a bad power loss and idleing problem which has been solved by a new MAF, these are very fussy engines and quite alot of people have been having problems with them

[mikeW]

Taurus, yellow epoxy that seals both throttle screws appears damaged, plus when the heads of screws when examined closely show signs of damage.
i applied a bit of forward pressure to throttle arm and revs started to drop, as soon as it's released revs go back up again

[Taurus]

In that case try resetting the throttle setting, it'll be trial and error so do it when it's hot.