Lost my idle circuit....

[takza]

Went to start my car after driving it the last time and no idle at all. Ended up adjusting the idle screw up so that it will idle sort of at around 1200 rpm.

Unless there is some miracle fix someone knows about....looks like I get to use my carb rebuild kit. I've never had this carb off the engine and the idle screw is still plugged.

Now about those miracles...got any????

[Gasoline Fumes]

TBI sounds good!

I'd check those solenoids on the carb. I think there's two? I believe they shut off the fuel while coasting in gear and/or when shutting off the engine. At least one should move with the key turned on. You could just temporarily hot wire both and see if you get an idle.

[pantah]

Went to start my car after driving it the last time and no idle at all. Ended up adjusting the idle screw up so that it will idle sort of at around 1200 rpm.

Unless there is some miracle fix someone knows about....looks like I get to use my carb rebuild kit. I've never had this carb off the engine and the idle screw is still plugged.

Now about those miracles...got any????

I have an 84 with a 3 AC motor. I think the plug is off from the carb idle, but I cant see or get a screw driver in there because the EGR bracket is in the way. Do I have to pull this bracket, or is there a special tool to reach the hard to get idle screw?

[ARCHINSTL]

It is certainly awkward, but the mixture screw can be adusted in situ.
I used a very short, ground-down, screwdriver.
Tom M.

[Petros]

Before I pull it appart I would check all the vacume lines to make sure they are hooked up, and none are cracked or leaking. Often a loose hose or vac leak will not allow it to idle. And if it is one of the fuel cut-off solinoids as Gasoline Fumes noted, rebuilding it will not bring the idle back unless you replace the bad part. It is also possible a chunk of crud got caught in the idle circuit, not likely if your filter is working correctly. Besides blowing it out with compressed air and carb cleaner, you might beable to back the idle screw all the way out (if the plug is removed), clean it out and replace the screw.

If it ran good before, likly it is something that just stopped working all of a sudden. That could be a solinoid or a cracked or loose vac line, or something similar. It has been my experinace with carbs (and unlike most of you youngsters out there I grew up with carbs but EFI is much better!) that when a rebuild is necssary it something that slowly gets worse and worse, not a sudden failure. the jets, check valves, passages, etc. slowly get filled with gunk and glaze or wear out, a little bit at a time, making it slowly get worse over long periods of time as you drive it. When something breaks it is just that that needs replacing or fixing.

[shogun]

as petros said it sounds like a nasty vacum leak, check for cracked hoses and pcv hose

[takza]

Haven't gotten around to checking it out...thanks for the ideas. Hope it's a simple fix....

Turned out to be a loose vac line on the pass side of the carb...though I ended up testing the solenoids also due to not plugging the vac line to the heat door after removing the air cleaner. Seems that ANY open vac line to the manifold causes NO IDLE! Duh.