83 305 wont idle

[Sachmo]

Posting this for a friend. the truck is an 83 k10 with a 305 and quadrajet carb. the valve cover gaskets where leaking so the covers were pulled and put on new gaskets and chrome covers. Now the truck will start by giving it some throttle and run great but just dies at idle. checked the carb for a vacuum leak and didnt find any. previous owner removed all emissions crap so vacuum lines are all plugged with screws. it doesnt even seem to try and stay running which leads me to believe the idle circuit is blocked. anybody have a similar problem? seems like an odd coincidence that a carb problem would arise after work was done on the motor.

 

[crazy4offroad]

What carb?

 

[Sachmo]

not sure on the carb looks to be a four barrel

 

[crazy4offroad]

Usually dirt in the idle circuit happens after messing with the fuel tank. I would re-check the vacuum lines, PCV valve, might want to replace the fuel filter too.

 

[Sachmo]

Every vacuum port is plugged. except for the one at the back running to the brake booster, the one up front running to the valve cover and the one going to vacuum advance. we're both stumped on this one. the entire ignition system has been replaced from rotor to plugs so that should not be a problem. the small fuel filter that goes into the carb is new as well. neither one of us have experience in rebuilding a quadrajet and arent all too willing to tear into it. any tips to clean out the idle circuit without totally rebuilding the carb?

 

[89Suburban]

Put the old covers back on it, lol....

Fist thing that I would look for is a vacuum leak like you said you already did. Don't know what else you would disturb changing valve covers.

 

[crazy4offroad]

When it's running try to listen for the leak, it should be pretty loud, unless the motor is really loud. Now that you say it is a q-jet, I'm no help for cleaning. Did you take the carb off to change the valve covers?

 

[Sachmo]

kind of hard to hear, but we dont hear any leaks. egr valve was removed to get the passenger side cover off. could a leak there be causing this????

 

[Sachmo]

LOOSE EGR VALVE!!!!!!! Started up and ran better than ever! took it for a short drive and it just died as soon i pulled in...... going to look at it tomorrow. oh the joys of a 30 year old truck

 

[bucket]

kind of hard to hear, but we dont hear any leaks. egr valve was removed to get the passenger side cover off. could a leak there be causing this????

Yes. What did you put back in place of the EGR valve?

 

[Sachmo]

The valve was on but not tightened all the way down. tightened it and presto.

 

[crazy4offroad]

 

[GOBR]

This happened to me the other day on a 5.3 at work. Didnt get the EGR tube back in all the way.

I was also gonna say if you think the carb had some junk it it you can get a friend to keep it runnin while you put both hands over the primaries and choke it down then pull your hands off real fast. Sometimes itll suck it thru.

 

[lusktommy]

LOOSE EGR VALVE!!!!!!! Started up and ran better than ever! took it for a short drive and it just died as soon i pulled in...... going to look at it tomorrow. oh the joys of a 30 year old truck

since all the emissions have been striped, id just take the EGR off and put a block off plate on it, but thats just personal preference lol glab you figured it out though

 

[gilbertjr04]

Usually dirt in the idle circuit happens after messing with the fuel tank. I would re-check the vacuum lines, PCV valve, might want to replace the fuel filter too.

Mine was doing the same thing and I had to get all the vaccum lines rerouted and also replace the fuel filter. It iddles better now. Carburetors are hard to deal with, specially the old ones. In California the carb has to be working almost perfectly in order to pass smog