2.0 Idle Speed

[Howard H]

I have a 1974 914 2.0. The engine starts relatively easy, but the engine idles at 1500 to 1800 rpm.

At what rpm should this engine idle, and what do I need to do in order to make it idle at that speed? Would appreciate any advise that I can get.

Thanks,
Howard

[Wayne 962]

There is an idle adjustment screw that should be located on the throttle body. I think that this screw has a spring wrapped around it to help keep it from turning under vibration. The correct engine idle RPM according to the manuals is 900 +- 50 RPM.

Make sure that your vacuum hoses are all in good condition, as a high idle can be caused by fuel injection problems such as bad hoses as well.

Hope this helps,

Wayne

[Paul914]

Definitely check that idle screw first, but there is also the ecu adjustment on the brain that will affect idle speed (enrichment too). If the vac hoses seem ok (no leaks), then it may be your aux air valve - you can check it by just blocking it off. Its supposed to close automatically when the engine warms up (idle at about 1500 or so when cold, and then fall down to the 900rpm range), but when the valve sticks/goes bad, the idle remains high.

-Paul