Car idles at 1500 no matter what I do.

[LO-vw]

I can play with the idle screw and kill it and open it up and somehow it will still find a way to idle at 1500.
It will creep up but eventually it idles at that speed.

Any ideas? Im guessing the car is now in open loop.

Car ran and drove great, then I did a hard launch and its been idling high.

[Prof315]

I can play with the idle screw and kill it and open it up and somehow it will still find a way to idle at 1500.
It will creep up but eventually it idles at that speed.

Any ideas? Im guessing the car is now in open loop.

Car ran and drove great, then I did a hard launch and its been idling high.

Sounds more like a vacuum leak to me

[corradolover1]

What sucks is WHICH vacuum line is the problem, because there's too many.
but, I'm sure if I had some time, I'd get the soapy water in a spray bottle and get to work!

[weejunGL]

check that small hose that connets the ISV to the intake manifold ,that one cracked on mine once. and i got high idle due to that

i've never seen 1500rpm out of a small vacuum hose break before, it has to be bigger then 3.5mm inner dia for that

[jeffs vw]

Or check the two behind the throttle body.

[LO-vw]

I can pinch the line to the ECU and the car dies.
I pinch any other line and nothing happens.

[jeffs vw]

Disconnect the ISV and plug back in.

[DigiMatrix]

Do not disconnect the ISV valve while running. Only disconnect and re-connect with the ignition off.

[crazynorweegian]

Do not disconnect the ISV valve while running. Only disconnect and re-connect with the ignition off.

Or better yet, with the battery disconnected.

I watched a mechanic do this recently. Get a vac gun (should be a free rental or max $30) and plug it into the ends of the vac lines in the bay. Draw a vac and listen for the hiss. You might have to pump pretty fast. I would say you have a blown off line. Good luck.

Edit: Quick tip, the only line that really matters for your idle that much is the ECU line. That, and the idle screw.

[DigiMatrix]

Edit: Quick tip, the only line that really matters for your idle that much is the ECU line. That, and the idle screw.

That or the Tee'd hose fitting between the intake, (above ISV) the throttle body and the carbon canistor. A split in this line will cause the idle to jump to 1500 RPM. Take it right off to check because it is usually on the bottom side.

[crazynorweegian]

That or the Tee'd hose fitting between the intake, (above ISV) the throttle body and the carbon canistor. A split in this line will cause the idle to jump to 1500 RPM. Take it right off to check because it is usually on the bottom side.

Very common.