Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor
Poor Idle On Rebuilt Carb
D Denzin:
I looked at the throttle plates, the secondaries close nice and tight. Primaries look good too.
I bought a new PCV and tried it. No Difference. I messed around with moving it from the primary side of carb to rear then from there to the intake. None of these location seem to matter. I didn't think they should but I tried. I'm going to move the PVC back to the front of the carb. I guess I'll have to run to town and pick up a couple of different pcv's and try them.
In the big picture it seems as I'm getting too much air somewhere. I'll have to take a second look at everything.
I checked for vac leaks with a unlit propane torch, any better way?
429bbf:
i use starting fluid to each his own . i agree with jim on the pvc i used to think they were all the same but there not. pull the pvc out of the valve cover or where ever it goes and leave it hooked up. put your thumb over it and slowly start restricting the vacumn and see what happens . hth you may also try plugging all the other vacumn lines ,brakes ,trans,etc. you never know where the problem is.
D Denzin:
I pulled the carb off Sunday and took a real good look at the base plate. No, the throttle plates don't close perfectly tight. By that I mean they close tight, can't close them up any more but You can see light around them if you hold them up to the light. Its a issue that the plates are a couple of thousands smaller than the bore side to side. I looked at some older unrebuilt carbs and they appear to be air tight but after cleaning the carbon and soot they have the same gaps. Not much can be done about it.
I had some other issues (leaking water pump) that I needed to fix. In the mean time I ordered a couple of different PCV's that I'm going to try. Not much in-stock in town.
I am only tapping the Q-jet for Vac for the PCV and Vac Advance for the dist. Car has manual brakes, manual trans.
I also drained the gas tank as the gas for the most part was over a year old. And I am replacing the add on fuel filter that was in between the pump and the carb. The filter looked to have some "milky" looking gas in it. Taking no chances.
So I have to wait for the PCV and fuel filter I ordered.
I also Changed the carb to intake gasket. It was a open one, I swapped it out for a divided one. I don't think it'll matter but it won't hurt.
Am trying everything I can think of.
77cruiser:
Are the throttle shafts tight?
D Denzin:
Throttle shafts are good. I rebushed the primaries using Cliffs Kit.
The secondaries aren't tightest fit I've ever seen.
I have checked and watched to be sure that the primaries always settle back to the same spot and I have tried to turn the primaries while running to be sure that they always seat back to the adjusting screw. No issues there.
I could try putting grease around the secondary while its running to see if that helps.
I'll put it on my list of things to try.
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