high idle dilemma -HELP! please!!

[str8up720]

Heres the set up:
318 Stock internals (besides mild cam)
LD4B edelbrock intake
1406 edelbrock carb ( with jets, needle, springs upgrade)
MSD distributor, 6al ignition box, ignition wires.
headers

Heres the issue I have been having ever since I swapped from the 2 barrel to a 4 set up. I haven't been able to have the engine idle below 2,000 rpms, and as it warms up it progressive increases. I have all the vacuum ports plugged up. Pcv and brake booster lines checked out. Sprayed brake cleaner around the intake and bottom of the carb, looking for a leak with no success. Timing is at around 40*btdc, but when I seem to retard the timing, it increases the rpms. I have been beginning to run out of ideas. Any one want to chimein and help me get my satellite back on the road!?

 

[Stewsta]

Adjusted the high idle?

 

[str8up720]

Fast idle is backed off. Idle screw is barely screwed in to barely keep it idling. idle mixture screw are backed off 1 1/2 ccw.

 

[HawkRod]

Adjusted the high idle?

X2.

In general check for any linkage that is hitting anything or binding. Maybe the throttle can't get back idle position.
Also, if you have a Holley with vacuum secondaries, check for interference with the manifold and the bottom of the secondaries. I had that happen once and the manifold wouldn't let the secondaries fully close.

 

[str8up720]

X2.

In general check for any linkage that is hitting anything or binding. Maybe the throttle can't get back idle position.
Also, if you have a Holley with vacuum secondaries, check for interference with the manifold and the bottom of the secondaries. I had that happen once and the manifold wouldn't let the secondaries fully close.

throttle cable looks fine to me. pulls and releases smoothly. nothing really to interfere with it as far as I can see. I checked the primaries and secondaries for binding and cannot fins any sigs of it. the electric choke seems to operate right. The carb is an edelbrock and I am fairly new to them, but reading the manual they seem to be easy to tune. I am wondering if one of the air bleeds may be clogged with dirt. It is a used carb. has anyone experienced any issues with a clogged air bleed on the carb? One other thing I found under my distributor. I found a lot of rust on all the parts under the distributor cap. could the advance springs possibly be causing this high idle?

 

[abloch]

Disconnect the throttle cable and remove that from the equation. Make sure the return spring is pulling the primaries shut. Check the kick down linkage for proper adjustment if you haven't done that already. my 2cents

 

[benno440]

timing too high? throttle blades not closing completely

 

[The Horvaths]

Get a flashlight and check that the throttle plates fully close. Gently run a feeler gauge or soft (copper) wire down there to feel it out if you need to. Primaries and secondaries should both be able to virtually seal shut at idle. If they won't close, something is binding or interfering. I have had to use insulating spacers on some applications to get a throttle linkage to clear. If they are closing, then I expect that you need to rebuild it. Inspect jet/rod sizes and verify that the jets are actually present and that they didn't get mixed up. Verify that the throttle plates are not mis-positioned on the shafts and preventing full closure. Verify that the proper gasket is intact and in place. Give it a fine-toothed comb approach. And take plenty of pictures.

BTW: 40 degrees? Da-yum! The RPM must have your centrifical advance kicked in. Depending upon the cam and it's phasing (as related to the crankshaft); I almost always start out with 8 to 12, vacuum disconnected. Typically 35-37 max w/centrifical by 3000 RPM and then work on vacuum advance.

- - - Updated - - -

Oh, hey, check that a metering rod(s) isn't stuck high too. Maybe there isn't enough vacuum to pull the springs down.

 

[furyus]

To start, cover the carb with a rag, and see if it dies. If it does, it most likely doesn't have a vacuum
Leak. Then do all the other suggestions already posted.

 

[GearAddict]

Back the choke off as it coulbe be holding the throttle plates open. I had this happen on my Holley and I couldn't get the idle down until I backed it off.

 

[The Horvaths]

Oh, yeah. Float setting or stuck needle valve will allow fuel to dump out vents and into carb. You should be able to see that.
I like the ol' "stuff a rag down its throat" approach. Good idea.

as well, pull idle mixture screws and check to see that they haven't been over-torqued. They could have the seats deformed and allow much more fuel to get by at 1 & 1/2 turns out.

 

[str8up720]

Just wanted to keep all you updated after a lot of trial and tribulation... I figured out the high idle issue I was having. after taking all of your guys advice, I started wondering about the distributor and ended up taking off the cap and rotor, after the rotor came off, I immediately noticed one of the advance springs was missing. It was really missing but rather rusted off and hanging around in rust pieces in the distributor. I guess what was going on was one of the centrifugal advances was opening at start-up causing the high idle. I replaced the spring with a spare, and voala! Began idling nice and calm the way it should, although when trying to set the timing, besides getting the hell out of me shocked, my timing marks where acting sporadically jumping all over the place. I have an advance timing light, and when I moved the dial so the timing marks lined up at zero, my dial on timing light indicated zero degrees advanced at 2500 rpm. My guess is I have a bad timing light, so I will verify that next. Thanks to everyone for the advice on such a simple yet annoying issue!