1997 Vectra 2.5 Sri idle

Hi all,

I've just changed the coil pack on my car which has made a massive improvement. I also changed the plenum hose cable ties for proper jubilee clips, which I was told was necessary, so I'm not sure what exactly the improvement is down to.

However, now another problem has reared it's ugly head. When I pull to a stop, the idle goes _very_ low (around 300!), then searches around

6-700, and it's quite rough. Sometimes it even stalls. Any ideas what this might be? I think there's a part called "idle speed adjustment sensor", but I'm not sure. This is the first modern car I've ever done any work on.

Antony

Reply to
Antony Gelberg
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It sounds like you have inadvertantly introduced an air leak, which is causing the poor idle- re check all inlet hoses and that you re-assembled the 2 piece inlet manifold with the gaskets making a good seal.

Check the PCV hoses.

Whilst you're at it, whip off the throttle body, and clean it throughtly- paying attention to removing the ring of carbon which will have formed behind the throttle disc. Flush the Idle valve out with carb cleaner also, and lightly re-oil- i used a dab of 3 in 1. Re-assemble with a new gasket.

Pull the ECU fuse or battery lead (radio code!) and let it re-learn idle characteristics.

Let us know how it is after that.

If its still poor, you may have an EGR problem.

Tim..

Reply to
Tim..

Antony Gelberg wrote in news:42637d6d$0$26353 $ snipped-for-privacy@news.zen.co.uk:

It's an idle control valve, take if off and give it a good clean out with carb cleaner, it might be a little gummed up and the engine (ECU) can't open it quick enough to stop the car stalling. However my Vectra 2.5 is prone to dropping revs like this, maybe down to

400rpm, as you describe, it's never stalled but it is disconcerting. I found a improvement was had by changing the lambda sensors which may have been getting a little slow in reacting to the exhaust gases. If they are over 60k miles old change them, clean the idle control valve and see how you go.

Keep well, and good luck,

Will

Reply to
Will

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