Thread: Idle

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I have a 283 small block in my 1991 Chevrolet s10... For some reason i can not get the idle under 1500 at idle.. I have a Spacer in between the 600 cfm holley carb... And i believe the timing is set right.. i just cant figure out whats goin on.. I have msd 6al ignition box, msd wires, msd blaster coil.. help me if u can please.

Check to make sure your timing isn't too far advanced. (how well does it start when it is hot?) Also, your fast idle cam might be engaged. (sorry, I didn't see that you said your timing was set correctly, disregard that part)

I'm thinking Vacuum leak. Start at the spacer plate and work around all the areas of the intake manifold. If all is well, lok at the carb for blocked metering plate passages. Dirt etc in the idle cicuits. But please start at the spacer plate for proper gasket sealing.

See whats wierd is i turned the air/fuel mixture screws allll the way in and it still ran is it supposed to do that?

nope, your throttle blades aren't closing.

What can cause that and how can i fix it?

If they're hanging up and not closing, Look at the spacer plate and gasket. It is a common mismatch for interference. No matter what you're gonna have to dig in and see.

yea it has to be something like that cus ive turned the idle screw alll the way to were its not even touching the throttle arm and ive turned the fast idle screw to were its not touching and all that and it still idles as 12-1500

The spacer has moved the carb far enuff to cause the throttle to apply.

The throttle has play .. i have the throttle linkange all the way down to were there shouldnt be any fuel coming into the engine at all and it still runs at 1500.

yea give me just a couple of seconds

Heres a couple if u need anything else let me know.. Im mind boggled

mod note: please resize pictures to 450X338 before posting then again

Wheres the gaskett or is there a gaskett between the top of spacer and carb?I see the gaskett under the spacer ,I just do not see one on top between carb and spacer......can you manually push the throttle linkage any farther towards the idle position,if so its like nitrowarrior said .

yea there is a gasket between the carb and spacer..

Just a silly thought. If the throttle plates are closing properly then I am gonna mention get a pair of needle nose pliers and pinch the vacuum line going to the brake booster. It has been known to happen that the diaphram is leaking vacuum and creates this problem. And how do you have the PCV hooked up?