Wierd idle problem...

[Pelon916]

This is a strange problem and I'd like some advice...

Please bear in mind that this problem has been happening since I got my truck, with 2 totally different carbs and intake manifolds.

Ok... my truck's idle is very high when it's cold, as though the choke were on.. but the choke is not even hooked up. If I tap the pedal the idle will drop to normal, but if I give it even the slightest bit of gas the idle jumps back up and stays there.
When I say high, I mean it will chirp the tires if I put it in gear, and if I drive it like that I can hardly stop because the brakes have to fight the engine.

The new carb and intake manifold did not change the problem at all. It is exactly the same.

When the truck is warm this does not happen. The idle is perfect. The throttle is not sticking, it works perfectly as well. This also happens if I manipulate the throttle directly on the carb with the linkage unhooked.

It has been suggested that I could have a vacuum leak to the tranny.. but I was under the impression that a vacuum leak would lower the idle, not make it sky high.

A problem with the distributer was also an idea. Maybe the vacuum advance or something is screwed up. But when the truck is warm it is fine.

Also, when I say cold.. I mean it's this way for about 10 minutes of running or more before it acts normal. After that it's fine for the rest of the day.

Any ideas?

[Pelon916]

not even a guess?

[bpmcgee]

Pelon,

What do you mean when you say your choke isn't hooked up?

There is a lever on the passenger side of a quadrajet that controls the fast idle speed. The way that it's generally set or unset is to hit the throttle. When this lever is in the activated position, it holds the throttle open at a point set by the "fast idle" screw on the passenger side under the choke.

This is what I would investigate.

If you have more information, I'd like to hear it.

Brian

P.S. This is an active board, but 40 minutes is a little unrealistic.

B

[Pelon916]

it's an edelbrock performer with an electric choke, the choke isn't hooked up.

i'll check that screw on the side of the carb, but this exact same problem was happening with a 2bbl carb with a divorce choke, both with the choke hooked up and with it disconnected.

the problem did not change at all from carb to carb and with a new performer intake manifold as well.

[Long Knight]

This might solve part of your problem...connect the choke. If it isn't getting juice (DC) it isn't opening. The DC goes into a heating element (coil) that opens the flap as it gets hot. If there is no juice going to it then it won't ever open all the way unless your engine is hot enough to heat up the element. I hear it's a good idea to hook it up to your alt. hot if you like to leave your truck while it's warming up...in case it quits the choke will stop opening and won't be hard to start.

[COBALT]

Even though you have an electric choke there still is bimetal inside the housing that can hold your choke closed without any power being to the housing itself. Without the electric choke hooked up it would be like your choke being on all the time! I'd suggest hooking the choke up to a 12v source from your ignition (and grounding the - terminal), or remove the housing if you don't want a choke.