Idle went down on it's own - 1977 2.7L

[kach22i]

My idle seems to of slowly gone down all by it's self over time.

To fix it, I just turned the idle screw near the airbox on the drivers side counter-clock wise (two full turns) to get it back to 900 rpm.

It was stalling out at rest (100 rpm). Yep that's 100 not 1000 rpm. I had to keep my foot on the gas and brake at the same time at a stop light. This is a trend that I did not notice at first, then one day became an urgent situation.

The idle screw is out pretty far now, any farther and I'm afraid it will come flying out on it's own (just a fear).

It's been about 7,500 miles since the last full tune-up.

I installed the Pertroix ignitor about 600 miles ago, but have not gotten around to re-doing the timing. Not a lot of low end power right now, re-timing should fix it.

.......................so here is what I want to do, 1) Install a MSD and redo the timing. 2.) Replace and re-gap the plugs for the MSD.

...................here is what I fear; Some little thing-a-ma-jig went bad or is going bad. Installing an MSD now will only make finding the real problem more complex later on.

Things that might make a difference: The pop off valve fell off recently. I reglued it a few days ago - as I adjusted the idle setting. This fixed some of my cold weather starting issues, and the hot starting issue which was short lived and gone now. Guess that pop off valve has got to be 100% air tight.

Could everyday vibration alone allow the idle screw to turn clockwise and reduce the idle?

Has adjusting the idle, fixed the symptom but not done anything to treat the disease?

Your thoughts......................

[kach22i]

This thread's going down on it's own.

[Paulporsche]

Have you checked your control pressures, your WUR and AAR? How about your CO%? If your control pressures are too low then you will get a too rich mixture, which will make you want to lean it as you have been doing.

Maybe you had an air leak prior to the popoff valvew coming out and either the WUR was adjusted by someone to make up for it, or the mixture was set richer to do the same.

Could your timing or distrib be off? Do these things have to be set differently when you install a Pertronix?

Maybe your sensor plate is sticking.

[SC-targa]

Vibrations wouldn't really turnt eh screw in. Your leaking pop-off valve could affect the idle. Sealing that up would lower the idle speed.

Jerry Kroeger

[Paulporsche]

See kpfoten's current thread.

[kach22i]

Originally posted by Paulporsche
See kpfoten's current thread.

Yea, that might be it.........I'm looking for something stupid like a lose screw (no jokes please).

Pertronix and 2.7: Engine Miss Solved

I'll pull the cap tonight and see what's shak'n.

[kach22i]

Originally posted by Paulporsche
Maybe your sensor plate is sticking.

I think might of been it.

I was stumbling around the airbox with the vacum attachments when re-gluing the pop-off valve. I could of bumped something.

This is my one week update.

Car ran great for a long ride this weekend.

This morning, while cold (idle was fine at 1,000 rpm), it kept bogging down under acceleration- had to back off on the gas or it would buck like a bronco.

Once warmed up idle was no longer 1,000 RPM, it had shot up to 2,000 RPM.

I turned the idle screw clockwise back to where it used to be before the troubles - and all is alright.

I'm idling at 950 RPM while warm...................and holding my breath.

Tomorrow is another day.

[Paulporsche]

Now that you have a good idle when warm, let us know what happens during a cold start and warmup. You could still have WUR, AAR, AAV, vacuum issues. Your sensor plate may be loaded up w/ grease etc, or your mixture control plunger could be gunked up.