Quadrajet idle mixture
Thread Starter
Instructor
Joined: Jan 2012
Posts: 215
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From: Mebane, NC
Quadrajet idle mixture
Car smells like it is running rich at idle. I see where to adjust the idle mixture, but no screw driver slot. All I see what looks like a thin oval head on the metering screw. Do I need a special wrench? My neighbor has a 69, he mentioned the epa covers that were on his. I don't think that is what I am seeing.
Burning Brakes
Joined: Jun 2003
Posts: 1,079
Likes: 1
From: Niagara Falls ON
Does it look like a "D"? That is a specific tool to keep regular people from messing with the mixture.
Has the carb been rebuilt? If not then it may not be as simple as adjusting the mixture...even if it has been rebuilt, if may not be that simple.
Has the carb been rebuilt? If not then it may not be as simple as adjusting the mixture...even if it has been rebuilt, if may not be that simple.
Melting Slicks
Joined: Oct 2006
Posts: 2,417
Likes: 336
From: Texas
it does take a special adapter to fit on the adjustment screws. i bought a flexible shaft adjustment tool with several different tips @ orielly auto. one of the tips fits the quadrajet mixture screws. also helps to have a vacuum gauge to get the best setting.
Burning Brakes
Joined: May 2008
Posts: 1,116
Likes: 5
From: Middleburg Florida
What year car is it (if it's an 81 and the carb is a E4ME that's a whole different animal), is it the original carb, what's been changed lately, did it just start "smelling" rich, are there other indications or performance issues? Help us help you.
The short answer is you might need a special screw driver, but that depends on what you have. You might have to remove caps to get at the mixture screws. Also, you should know that smelling rich doesn't necessarily mean it's rich. A lean condition can cause that too.
The short answer is you might need a special screw driver, but that depends on what you have. You might have to remove caps to get at the mixture screws. Also, you should know that smelling rich doesn't necessarily mean it's rich. A lean condition can cause that too.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
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From: Oxford MA-----You just lost the game!!!!
Car smells like it is running rich at idle. I see where to adjust the idle mixture, but no screw driver slot. All I see what looks like a thin oval head on the metering screw. Do I need a special wrench? My neighbor has a 69, he mentioned the epa covers that were on his. I don't think that is what I am seeing.
Doesn't it **** you off, dealing with something that somebody else intentionally made more difficult, just to try to keep you from screwing around with it? Now you'll be able to adjust your idle screws with a flat tip screwdriver, as God intended!
P.S. Spray a little carb cleaner through the hole that the screw comes out of, and clean the screw up, too, it's probably pretty cruddy!
Keep the shiny side up!
Scott
Thread Starter
Instructor
Joined: Jan 2012
Posts: 215
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From: Mebane, NC
more info
Can't answer most of the history questions. Car runs fine on the road, just smells rich idling when I'm working on it, just wanted to check the mixture.
Carb # is 17084288 1994 HKF
Carb # is 17084288 1994 HKF
Tech Contributor
Joined: Aug 1999
Posts: 14,385
Likes: 6,414
From: At my Bar drinking and wrenching in Lafayette Colorado
But...
I'll bet your problem is not with idle mixture - it's almost impossible to adjust a lean-run '84 carb to run so rich at idle that you can smell it. More likely, your timing is off or you have internal carb problems.
Lars
Thread Starter
Instructor
Joined: Jan 2012
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From: Mebane, NC
Thanks Lars for the wrench tip. The carb is on a '73, why do you think it is a "lean run 84"?
SpeedReed, I didn't have a vacuum gauge growing up. It was always turn the screw in til the engine got rough, then back out a 1/4 turn. What am I looking for when I'm setting the mixture....I would guess, max vacuum?
SpeedReed, I didn't have a vacuum gauge growing up. It was always turn the screw in til the engine got rough, then back out a 1/4 turn. What am I looking for when I'm setting the mixture....I would guess, max vacuum?
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Brett Foote
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From: At my Bar drinking and wrenching in Lafayette Colorado
Burning Brakes
Joined: May 2008
Posts: 1,116
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From: Middleburg Florida
As suggested by Lars, I'd be checking the timing too. If you do end up rebuilding it, what are you going to buy the kit for? Your car or an 84 truck? You'd do well to email Lars for his recommendations and papers on tunning and rebuilding...just say'n....
Thread Starter
Instructor
Joined: Jan 2012
Posts: 215
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From: Mebane, NC
Now that I know it's an 84, that's the kit I would order. The car has a crate motor in it, just over 1200 miles since installed. Checking the dwell, timing, etc was one of my first chores. It is now on spec, still smells.
Burning Brakes
Joined: May 2008
Posts: 1,116
Likes: 5
From: Middleburg Florida
Ken, I'd still suggest pinging Lars for his Q-jet papers. He forgotten more about these things than most of us will know, and he's willing to share. It'll save you time and headaches I promise.