Idle speed changes
Well, I don't own any show cars or hot rods, but I consider my 79 Jeep CJ5 with a healthy AMC 360 to be my hot rod, and I am hoping to find some help here with my idle issues. So....we use this Jeep as a nice day cruiser and an offroad vehicle. The problem is when the jeep is ran moderately hard, the engine will not "idle down" or return to idle. The first time this happened, we were out driving over the sand dunes here in Michigan, running pretty hard in two wheel drive. We didn't quite get up and over the top of the dune, so I pressed the clutch in and found reverse to make our way back down. Once down to the bottom, the motor only idled down to @ 1500 rpm instead of the previous 900-1000 rpm. I took notice and made the hill again, and the issue somehow resolved itself. The next time this happened, it was the exact same situation, but on a different hill. And instead of the 1500, it only came back down to 2000 rpm. On this second occurence it was on the last of the dunes and we headed back to camp, and there was no change in idle speed. After a few hours of sitting at camp, fired it up and no change. A few more hours gone by, still no change.
So, at this point we decide to play with the timing a bit, and got it to idle down, but before we changed the timing, it was very easy to turn the distributor without loosening the hold down clamp, but the bolt was still tight.
Once home, I played with the timing again, got it where I thought I wanted it. TIGHTENED the bolt, free revved the engine, idled down to 1500. So, thinking we could have somehow bent the hold down, tried to bend it back and reset the timing. All seemed well. Next day went to a local cruise in town and things were good for say 45 min of running, then idle jumps up to 1200. Again reset idle timing, and all seemed well. Drive it nice and easy for a few days, then today during a moderate acceleration, idle jumps back to @1500 rpm.
So where do I go from here? It is an MSD dist.
My thoughts are:
While I am playing around with it all, I noticed some white powdery corrosion on the rotor and pickups under the cap, so get new rotor/cap.
- Try a new hold down clamp?
- Possible worn dist gear?
- shim between the hold down clamp and dist base?
I did not build this motor, and I am only beginning my quest here on motors, so any helpful thoughts/advice/suggestions, I will be grateful. Thanks for your time.