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Engine cuts out when idle.

Posted: Tue Jun 06, 2017 5:57 pm
by BradsCav
I have a Mk 3 1.8i GLS Auto Cavalier, the car drives really smooth even after covering 161,000 miles, but whenever the car is idle is is very juddery and shakes about a lot, if put into neutral it is better but not perfect. But sometimes when I'm reversing into the drive, and the steering is on full lock and going slow, the engine will switch off. I don't know much about mechanics so any help would be much appreciated. I'm not sure if the injectors are blocked or something as it is fine when the revs are higher, and sometimes the car won't start at all, I may have to try several times. Does anyone have any idea what could be at fault?

Re: Engine cuts out when idle.

Posted: Wed Jun 07, 2017 7:47 am
by cavalier1990
This is the single point injector model? Or is it older multi injector, or even older carb? Has fault developed slowly over time, or become apparent quickly, has anything been done to car recently, what is service history like, last time plugs, distributor, leads etc been changed. With things like this you need to go over service items if you don't know history of car. Rule out those plus air leaks first. What is standing idle value, should be about 800 rpm + 50 for auto, if it's low, might be blocked idle control valve or gummed up throttle valve/intake.

Re: Engine cuts out when idle.

Posted: Wed Jun 07, 2017 11:31 pm
by Robsey
It looks like it is a facelift 1.8 single point injection judging by his description.
"GLS 1.8i"

Cutting out at idle?
Usually an idle control valve or a small induction air leak.

Re: Engine cuts out when idle.

Posted: Thu Jun 08, 2017 1:45 pm
by cavalier1990
Robsey wrote:It looks like it is a facelift 1.8 single point injection judging by his description.
"GLS 1.8i"

Cutting out at idle?
Usually an idle control valve or a small induction air leak.
Good as well to check inlet manifold for leaks on those, it's common problem the gasket falls apart, causes crappy idle although I actually never had mine cut out on me.

Re: Engine cuts out when idle.

Posted: Fri Jun 30, 2017 8:39 pm
by BradsCav
Its a problem that came up quickly, it didn't build up over time. Sometimes there is a problem when the engine is warm, after driving somewhere for example, and when I return, say after 20 minutes and I try and start it, it won't start, I may have to wait 10 minutes or so, if I hold the key on longer you can hear it struggle to start, if I press the accelerator a bit that sometimes helps it to get going. But I will look at the points you all mentioned and will see what happens. The car has been in the family for 15 years so there is plenty of service history.

Re: Engine cuts out when idle.

Posted: Fri Jun 30, 2017 8:55 pm
by Cavalier342
From experience of owning that engine and transmission in my old LS, I'd definitely look at what's been mentioned, maybe worth removing the idle control valve and spraying it with carburetor cleaner, it's located just under the throttle body, facing towards the engine block, 2 small grub screws hold it on. It could also be the MAP sensor, located under the scuttle panel flap (above engine bulkhead), with a couple of hoses and a plug running from it. One hose leads to the rear of the inlet manifold, easy to see/get to. If that's clogged or split, that could cause idle issues as the MAP sensor requires vacuum from the inlet manifold to work.

Andrei.