Cavalier idle speed - Dan J
I have a 93MY 1.8i Cavalier. The idle speed is a little low on the car and the injection system frequently "revs" the engine as it thinks the car is about to stall. The throttle stop appears to be on a thread but you cannot get to the other side ie screw head to alter it (blocked off with what appears to be solid metal). Anyone got any ideas of how I can adjust this or do I have to go to a Vauxhall dealer and doubtlessly pay god knows how much to have the injection system corrected?
Re: Cavalier idle speed - Richard Hall
I don't know anything about 1993 Cavaliers, but I am still prepared to bet that your idle stabilization valve is clogged up and sticking. It has to be the most common cause of idle problems on 1990s fuel injected cars. You can try removing it and blasting the inside with carb cleaner - doesn't always work, but what do you have to lose?
Re: Cavalier idle speed - Ian Aspinall
Yep, it's particularly common on Mk3 Cavaliers. There are some instructions on how to clean out the idle control valve in the "How2" section at:
Re: Cavalier idle speed - Dan J
Many thanks to both of you for your comments - I'll give it a go!
Re: Cavalier idle speed - John Slaughter

A common problem on Vectras too. While you're doing the job, carefully clean the throttle body and butterfly too, and make sure the ports connecting to the ISCV are clear. If cleaning doesn't fix it - and it often doesn't - a new idle speed control valve is probably needed. You don't say how many miles the car's done, but replacement of the ISCVs is pretty common after 50k + miles.


Re: Cavalier idle speed - Adam Going (Tune-Up Ltd)

As well as the throttle body and idle speed control valve, it is essential to clean the crankcase breather vacuum port (follow the smaller of the two hoses from the cam cover to where it enters the inlet manifold below the throttle body).

The idle control valve is notoriously troublesome, and if you buy a new one from Vauxhall you will find it has a new part number indicating a modified unit.

Regards, Adam

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