Idle too high
 

Okay I have another one for you guys. My 1991 turbo sits at 1500- 1600 Rps at idle how can I ChangE it to be a oem specks of 600 to 700 rpms? I can't locate the idle screw need some help.

Thanks Aaron

There's an adjustment screw on the throttle body.

...that should never need adjustment. The only time you should mess with this screw is if somebody else has already done so.

Everything on these cars is computer controlled, so if it's idling high there is a problem somewhere. Check the simple stuff like ignition timing, cam timing, vacuum leaks. Check for engine codes (just because there isn't a code showing doesn't mean there isn't one stored). Post back with what you find

Check the tps that's what was causing my high idle.

The timming is set perfect. But the tps might be the problem this is a jam engine so it could have been tampered with. I know it's electronically finds the best timing and idle for the car but 1600 is way too high how do I check it using the diagnostic plug what do I jump in the diagnostic plug to find the problem. Lol kinda do t know how to read it either I'm a newbe guys.

See the MKIII FAQ section for the thread on how to check codes.... Generally a good place for a newbie to spend a LOT of time.

I checked the codes and I think I'm going to start with tps. I had codes 41 and 52 pop up so I'll be replacing that in the morning I actually have one from my old engine. Never thought it would be a dang sensor god this car has so many electrical componets lol. You live you learn but I'll post something tomorrow hope it does the trick. Thanks guys!

52 is the biggie of those codes. I'd attend to that first. Typically it's a wiring issue, not the knock sensors themselves. Look again in the FAQ section for a thread on knock sensor problems or knock sensor rewiring.

Also, check if the mixture screw on the KVAFM has been tampered with. If it hasn't there will be a press fit plug hiding it in its cylindrical housing... otherwise the plug will have been drilled out.


***Could someone post a picture of the mixture screw on the KVAFM and also check if there is a two digit number near it? It should be the same as the VAFM when it comes to adjustment (see the new FAQ on this).

Sorry it's codes 42 and 51 I had them mixed up, but bot was I scared about code 52. 42 I think is because my speedo cable is broken. But I tried to change the tps man they don't make an easy part to take off!!!!

You'll get both og those if you unplug the TPS while in diagnostic mode. Code 51 will occur if you just tap the throttle. Code 42 will only be caused by a failure or unplugging it.

It's easy enough to get off as long as you use the right size screwdriver... Pulling the throttle body and putting it on your workbench REALLY helps. ;)