MN80Vette

I drove my '80 to work today and took the freeway. Traffic was moving right along at 70-80 mph. (And that's the right lane. Stay out of the left lane if you're not going faster.) After 10 miles or so, traffic came to an abrupt halt and changed to stop-and-go.

Normally my car idles at about 600 rpm, but when I slowed suddenly and joined the stop-and-go traffic, it was idling at 1600 rpm. Nothing I tried slowed it down. The choke didn't seem to be stuck closed. (That happened once when one of the wires came off the electric choke control, so I know how the car runs when the choke is stuck closed.) The throttle didn't seem to be stuck.

Managed to get to work without over heating. I shut the car off, popped the hood, and removed the air box. The choke was wide open, both wires were still attached, andthe throttle was resting against the idle screw.

After a couple hours of meetings, I went out and started it up again. Idle was normal, the choke only stayed closed for a little while like it's supposed to (idled at 1000 rpm), then opened like it's supposed to (idle dropped to 600 rpm like I expected).

So, what could have caused the idle to be so high after the 10-mile cruse on the freeway?
I've noticed it idled faster after cruising on the freeway, but never this fast.

Under the hood:
* GM 350 HO Deluxe crate engine (330 hp, 380 ft lbs torque)
* Holley 600 cfm 80457S (basically an 1850 with an electric choke)
* BW Super T-10 4-spd

SIXFOOTER

Sounds like one of the choke levers stuck. Wnen you shut it down the choke pulloff might have kicked it loose. Look over all the rods and levers on the passenger side and see if anything jumps out at you. Maybe Lars or someone smarter than me will chime in

SmokinBBC

Here's a stretch..but it happened to me.

My advance weights were hanging up and didn't return to normal postion when decelerating down to idle. In effect keeping the dist. a little advanced...caused my idle to sit at about 900rpm's versus the normal 700 at idle.

Couldn't figure it out until one day I shut the engine down at the high idle and pulled the cap and rotor.....

MN80Vette

That was the first thing I suspected. The choke was wide open when I checked it in the parking lot.


Hmmm. I didn't even think about the timing/distributor. I changed weights and springs about 6 months ago. In hindsight, how can I tell if the weights were hung up after shutting the car off? How do I fix that problem (if that is the problem)?

SmokinBBC

Next time it happens, shut the engine off and remove the cap and rotor. Inspect the weights. One of my weights was slightly stuck out and didn't return to the normal position.

MN80Vette

The more I think about it, the more I suspect the timing/weights. I had timing problems, especially when accelerating. That's why I changed the weights. The problem developed over time. The 350 HO ran like a top until the last few weeks or so.

So, if one (or both) of the weights are stuck out, what do I do about it? Is there some kind of lube I can apply?