cold weather - very high idle, 3500 rpm at startup Options

[cassidy_bolger]

My '73 2.0 sat for a week while I was on vacation. I fired it up this morning to head to work, and the idle was super high - 3500 rpm. It has been cold (for this area) last night's low was 30. I tried to back it up and see if things would calm down, but running it made me nervous and I was late for work so I took my backup vehicle. This 914 has been driven nearly every day and has run well since I bought it last spring, so this is unusual.

Where should I start? I checked the throttle cable at the engine, and it isn't stuck. Is something frozen? Should I just try to drive is a few blocks and warm it up?

Thanks,

cassidy
73 2.0

[r_towle]

warm it up.
If your AAR valve is stuck, it will never really idle low.
The AAR valve is for cold starting and it adds extra air to make it idle faster.
If its stuck, I am told that it can be lubed and unstuck
I just removed mine. I let the car warm up, then drive.

Rich

[drewvw]

you can try spraying some pb blaster in the AAR and see if that helps.

Another thing to check might be to see if your PCV valve/hose came loose, i did that once and it idled right up at 3500.

[cassidy_bolger]

thanks, I'll look into it.

maybe a little heat in the garage wouldn't hurt either.

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[Air_Cooled_Nut]

Start her up and let her "idle" for about a minute. If the rpm doesn't start to slow down, and eventually hit normal idle rpm, then your AAR is likely stuck open. It's normal for a high idle until the AAR warms up (it's electrically heated, thus the wire coming out from under it) and should drop the high rpm around a minute or less.

A properly functioning AAR makes cold start-ups and driving easier until the engine reaches operating temp. I removed mine and it was a bitch to drive in traffic (stop-n-go) without killing the engine until the engine got hot (not warm) enough to idle well without dying.

[jim_hoyland]

Been down this road and the above are possible. You gotta really check out all the lines that connect to the plenum, especially the small ones that look ok. I opted for a vacuum gauge to monitor any changes in the vac. If the small lines are old, try bending one between your fingers----if its snaps/breaks, you prolly got weak hoses.

At one point, when a similiar situation occured and before the vac gauge, I began removing each piece that feeds into the plenum. Decel and ARG went, took the AAR out ( temporary ).

This is clearly a challenge, good luck----

Jim

[cassidy_bolger]

Problem solved, classic lessons learned - again.
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The hose going into the box out of which comes the oil filler neck (crankcase breather perhaps?) was loose. Plugged it in and back to normal. For giggles, I unplugged it and the idle shot back up to 3500. Turns out, I knocked it off when I topped off the oil this morning.

The only other time this car has acted this badly, it was also my fault - I had accidently loosend the wire harnes at the pressure sensor while installing a new battery.

So it is final - I am a clutz. One must think twice before blaming the car, eh?

Thanks for the help gang. Good to see things are up and running.