Q-Jet making car run too rich
07-10-2003, 02:54 PM
#1
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Q-Jet making car run too rich
Hey guys,
I have a 305 in my bird (stock 86 LB9) engine, with an Edelbrock performer manifold, topped off with a non-CC Q-Jet. The problem is that the carb (and manifold) was off my old 350, so when I stuck it on the 305, the engine runs VERY rich, I can smell the gas in the exhaust. Timing is right on, yet the car has no power whatsoever.
How would I make the engine run leaner. I am also a newbie when it comes to carbs (worked with TPI mostly) so can somebody please explain to me how to fix it in depth.
BTW I suspect the secondaries aren't opening, how could I check this?
Thanks for the help,
-Max
I have a 305 in my bird (stock 86 LB9) engine, with an Edelbrock performer manifold, topped off with a non-CC Q-Jet. The problem is that the carb (and manifold) was off my old 350, so when I stuck it on the 305, the engine runs VERY rich, I can smell the gas in the exhaust. Timing is right on, yet the car has no power whatsoever.
How would I make the engine run leaner. I am also a newbie when it comes to carbs (worked with TPI mostly) so can somebody please explain to me how to fix it in depth.
BTW I suspect the secondaries aren't opening, how could I check this?
Thanks for the help,
-Max
07-10-2003, 05:41 PM
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Q-jets were notorious for a couple of things - floats becoming saturated with fuel, and leaks from lead plugs located under the fuel bowl. Either one would cause a rich condition.
Calibration of q-jets varied widely as well, depending upon the application for which it was built. If you have one off of a big cube engine before emissions was a big deal, it could be way off for your engine. Retuning at a minimum required.
You can check for the secondary throttle blades opening with the engine warmed up (choke off) and engine off. Push on the air valves (secondary plates on the top of the secondaries), look down while you open the throttle fully. You should see the secondaries open. As for the AV opening, you can best tell that by adjusting them loose until you get a bog, then tightening them up to make the bog go away (see tech articles on this board).
Calibration of q-jets varied widely as well, depending upon the application for which it was built. If you have one off of a big cube engine before emissions was a big deal, it could be way off for your engine. Retuning at a minimum required.
You can check for the secondary throttle blades opening with the engine warmed up (choke off) and engine off. Push on the air valves (secondary plates on the top of the secondaries), look down while you open the throttle fully. You should see the secondaries open. As for the AV opening, you can best tell that by adjusting them loose until you get a bog, then tightening them up to make the bog go away (see tech articles on this board).
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