cast your vote for what's my problem......
Car idles high after i run say 2000 rpm for 10 sec. or more it will idle around 1100, after 1 minute it slowly comes back down to the 900 i set it at.
blades are closing as far as it's set to
timing LOCKED at 34*
holley 830hp (there are holes in every throttle blade, and i don't know if it's factory or not)
454 with big street cam
only vacuum is the power brakes running off the #7 runner, and pa PCV running off a spacer plate (carb has NO ports)
plugging the p.b. port didn't change anything, plugging the pcv helped bring it down quicker only before i locked out the timing...

im stumped. along with an 1800 rpm dead lean spot (a/f meter) im frustrated.

sounds like the vacuum advance on the distributor's shot. But now that Ive said that you probably aren't running one. Jason.

sounds like the vacuum advance on the distributor's shot. But now that Ive said that you probably aren't running one. Jason.

timing is locked out, no vac. advance on this dist, it's a MSD pro-billit, i locked it thinking the springs were weak and the weights were pulling the timing up just enough to idle it up more than slowly come down.... WRONG

timing is locked out, no vac. advance on this dist, it's a MSD pro-billit, i locked it thinking the springs were weak and the weights were pulling the timing up just enough to idle it up more than slowly come down.... WRONG
Power valve?

I thought I had the answer until I read that you locked your timing.

That sounds like the exact problem I was experience a couple of years ago.

The idle rpm's after driving or elevating the rpms off idle would be about 150-200 rpms higher than where I originally set it. After a minute or two it would slowly drop back to where I originally set it.

It turned out to be weak advance springs in my MSD Pro Billet distributor.

This is very likely an intial timing/vac advance/mech adv tuning/dialing in tuning problem.

You only state your timing is locked @ 34 deg but never state your INITIAL TIMING which could be your problem or at least partly if your running TOO RETARTDED.

If your running a perf cam of any kind you will need apporx 16-18 deg btdc intial timing (with vac plugged if using one) so chk it and if it's too retartded then advance it.

If you do advance the timing should help and you will likely need to lower your idle a little and also may need to limit your mechanical if your total timing
ends up too high causing detonation or a derease in perf.

If you still have problems after doing the above check the springs on your mech advance to make sure they are not too weak allowing the mech advance to activate at low rpm close to or at idle speed. If you suspect this is happening too then just put in a little heavier spring to test it out.

Scott

This is very likely an intial timing/vac advance/mech adv tuning/dialing in tuning problem.

You only state your timing is locked @ 34 deg but never state your INITIAL TIMING which could be your problem or at least partly if your running TOO RETARTDED.

If your running a perf cam of any kind you will need apporx 16-18 deg btdc intial timing (with vac plugged if using one) so chk it and if it's too retartded then advance it.

If you do advance the timing should help and you will likely need to lower your idle a little and also may need to limit your mechanical if your total timing
ends up too high causing detonation or a derease in perf.

If you still have problems after doing the above check the springs on your mech advance to make sure they are not too weak allowing the mech advance to activate at low rpm close to or at idle speed. If you suspect this is happening too then just put in a little heavier spring to test it out.

Scott

SCOTT, you noticed that i said it was locked at 34*.... that means LOCKED at 34* there is no initial difference, it's 34* all the time..... thus me locking it out, because as you and others have stated, i was thinking the same thing....



just an FYI i started it today, and took it out and down the highway, NO DEAD SPOT and NO IDLE issues, UNTIL :( i blasted it down the service road (ran great) and there it came back, dead spot and idle up again
I sprayed carb cleaner at all the vac. fittings, and around the intake/carb base looking for a leak, none,

I'm going to go out a limb just a bit here, John. It's possible that you may have set the idle speed and mixture while the carb was running in a rich condition. Thus, when you rev the engine, it clears the extra fuel momentarily and when it comes back down to idle speed, the fuel / air ratio is closer to where it's supposed to be, until it loads up again. This could be a dribbling power valve, or a float that's set too high. They actually can hold an idle and you can tune it to idle smoothly, even in a slightly rich condition.

This is sort of the reverse of a lean idle condition. When you have a lean idle condition, you can actually make the engine idle smoother by placing your hand over the carb air intake and slowly close off the airflow. In your case, John, I think you're running slightly rich.