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High idle, first tests

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drooartz

drooartz

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To summarize, the Tunebug started fairly suddenly to have a high idle, around 2000 - 2200ish. Suggestions came from the forum to check the throttle cables and such to see if it was binding. Here's what I did:


1. Made sure there was oil in the dampers, each took a little.

2. Removed the throttle cable and choke cable completely. Throttle cable will be replaced, but it did not seem to be bound up anywhere.

3. With cables clear, I applied a bit of choke with 2 fingers, throttle with 2 more, and reached across the engine bay and pulled the starter. I love cable starters! Car started up fine, and still ran fast.

4. Blipped the throttle, lifted the levers that get pulled by the choke, raised each piston a bit.

Car still idles fast. Lifting a damper piston makes the car stumble and run slow. lifting the little levers that the choke pulls lowered the RPM.

What do I test next?
 
u might have worn throttle shafts letting air in or maybe adjusting ur timing might help some........
mine idles high also, but only around 1500 rpm...........z
 
The strange thing is that it seems to happen suddenly. The car was idling at around 900 or so, and maybe 10 miles later it was at this fast idle.

I was on the freeway, and the only thing I can remember is that I blipped the throttle to downshift to third for an uphill section right before the off ramp, and it revved a bit high (4-5k I think). Other than that, it was an uneventful 10 miles.
 
Sucked the crude/dirt out that was sealing the leak! Now you have to find the leak. (i'm taking a wild guess here)
 
[ QUOTE ]
The strange thing is that it seems to happen suddenly. The car was idling at around 900 or so, and maybe 10 miles later it was at this fast idle.

I was on the freeway, and the only thing I can remember is that I blipped the throttle to downshift to third for an uphill section right before the off ramp, and it revved a bit high (4-5k I think). Other than that, it was an uneventful 10 miles.

[/ QUOTE ]

Drew,

I wonder if something happened to one of the butterflies that's causing it to hang partially open(?). To check for sure, it would probably require you to remove the carburetors (not a big deal really).

If the butterflies are closing properly, you should be able to get the idle down to the point where it will basically stall and die. Worn throttle shafts/bushings or other vacuum leaks that allow air to enter without passing through the carb openings should not prevent you from lowering the idle speed. Typically, those type problems would just prevent the car from running or idling smoothly at lower RPM. It would just stall and die at a higher RPM (due to a lean condition).
 
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