90 GTI 8v Trouble...

[GTIMatt]

Hi folks..

I've read a few threads with people having very similar problems, but not found a fix from what has been suggested so far... here's what happened.. Been driving 15/20 mins or so. Not working her too hard, oil temp 86, so no worries there. Wafting down a local bypass, I put my foot down and nothing seems to happen- a bit of a delay then a judder, and another. Then the engine cut out.

So now the engine will start, but with VERY high revs, sounds rough as a dog (misfiring, popping, spitting ), and will cut out if I don't give it some throttle.

Someone suggested replacing the idle control module (the little 7 pin connector under the rain tray above the ecu), so I did that and it made no difference. Checked all the pipework for air leaks, not found any. Checked earths and the ECU one is maybe questionable, looks a bit grotty but the shrouding of the wire has come away anyway down there and the wires are exposed and touching the block, so surely that would be giving a good earth?

Pretty lost here really, I can't decide whether it's a fuel (pump, injectors?) or electrical (icm, ecu?) problem. Getting a bit disheartened now, my 2nd big breakdown in 6 months of owning it

Any tips or tests I can do to try and pin point the problem?

Thanks a lot folks

it.s a digi PB btw

[rubjonny]

disconnect the plug from the main pump, and turn the key 1 click. you should hear the in-tank pump prime, if not thats your problem. the wire you mention sounds like the knock sensor to me, best to find another as it wont be doing it any favours, but I doubt it would cause these symptoms you mention. most VW/Audi 2.0 lumps will have one that'll do the trick, just make sure you do the retaining bolt up to the right torque

[GTIMatt]

Thanks for the quick reply...

Where will I find the plug for the main pump? 

[peaky83]

In front of the rear offside wheel behind the jacking point.

Ta,

Dan

[GTIMatt]

Found it! Cheers Dan 

Disconnected power but can still hear a noise (from the back) when I turn the key 1 click, so that must be the other pump working fine?

[Alec]

When mine had the same kinda symptoms it was the dizzy cap and rotor arm that sorted the problem out.

[TreadGingerly]

There's a mechanical device on top of the rocker cover that has summat to do with tickover etc... I had similar problems, including engine revs surging. Removed this (someone will come along and tell us what it's called) and soaked it in carb cleaner overnight. Works fine now.. Might help ?

[jezza16v]

I think you mean the idle stabilisation valve, but this shouldn't have any affect when running at speed because its turned off as soon as you press the pedal.

[GTIMatt]

When mine had the same kinda symptoms it was the dizzy cap and rotor arm that sorted the problem out.

Had new dizzy, cap, and arm at Christmas.

Idle stabilization  valve is a good call but that wouldn't make it run so rough surely?

Is it possible my timing is out?