Mysterious idle change

[glassman]

Hey all, so I have a zz3 small block in my 70 cam, just installed a Dakota digital VHx setup and rebuilt the t56. It sat for seven weeks and all of a sudden it won't idle below 1500 rpm. I didn't play with the distributor, cause it seems like the timing is off.

The carb is a Holley street avenger 670.

Is something stuck inside? Choke?

I checked around the carb base, no leaks, plugged every thing up, still nothing.

Any suggestions would be appreciated.....thanx, mike

[GregWeld]

Originally Posted by glassman

Hey all, so I have a zz3 small block in my 70 cam, just installed a Dakota digital VHx setup and rebuilt the t56. It sat for seven weeks and all of a sudden it won't idle below 1500 rpm. I didn't play with the distributor, cause it seems like the timing is off.

The carb is a Holley street avenger 670.

Is something stuck inside? Choke?

I checked around the carb base, no leaks, plugged every thing up, still nothing.

Any suggestions would be appreciated.....thanx, mike

With todays crappy gas -- anything is possible - you could have a stuck float - so I'd gently tap the float bowls on the top.

Also - you could have some sticky advance cams in the distributor.... it's winter and rust can and does take hold... so I'd be pulling the cap and examining the distributor internals.

Then I'd turn the idle adjustment screws in all the way til they seat - counting the turns - do one at a time - and backing them out the same amount so you come back to where they were... this can "break" any varnish that may have formed on the needle and seat.

I'd also make sure that the mechanical RETURN on the linkage is actually allowing it to return to the idle adjustment screw stop.

[glassman]

Thanx greg, the idle stop (the mechanical) i got. I think its timing related or internal carb related, the cap is easy, well for that matter, so is the carb. Time to pull her apart....thanx

[Vortech404]

Happen to my idle on my 96 camaro 1 time. It ended up being a cracked vacum line on my throttle body. Worth a shot to check them.

good luck
John

[glassman]

thanx John, ill check that too, where did your crack at?

[Vince@Meanstreets]

If you have an electric choke check to see where the 12v ign feed comes from. Might have been changed or affected due to the gauge installation.

[dontlifttoshift]

Disconnect the throttle cable from the carb.

Check idle speed.