Author Topic: How to eliminate off-idle bog  (Read 1845 times)

Offline bcarlson78248

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How to eliminate off-idle bog
« on: October 22, 2018, 06:11:03 AM »
Quadrajet 17080213 Q243 CPX
A few months ago I made changes to my engine and got some updated carburetor parts from you to get it running better with the new heads and cam.  That discussion is in this posting
 - https://cliffshighperformance.com/simplemachinesforum/index.php/topic,3763.0.html .

The truck runs well overall, but still has a very brief bog/power drop at certain times off idle.   

If I let off on the throttle to turn a corner or slow down for a light, and then hit the throttle lightly again for slow acceleration out of the turn, power drops out for a fraction of a second and then it catches up and accelerates if I give it more pedal.    It's not really noticeable if you accelerate quickly off the line, but I think it still may be there.

Where should I start to reduce this power drop?  AFR at idle looks fairly normal at about 14.5-15 and it idles smoothly.  Cruise AFR looks lean to me (about 17) but I don't know if that has any relationship to the off-idle drop.

Would it help to try adjusting the APT, or is there something else I could try?   Would I turn the APT out or in to resolve this problem?  I have the carb drilled so that I can unscrew a plug and reach the APT without pulling the top off the carburetor.

Thanks,

Bruce

Offline 429bbf

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Re: How to eliminate off-idle bog
« Reply #1 on: October 25, 2018, 06:30:24 PM »
i would try 2 things. first would be running without air cleaner  second would be screwing the apt out 1 turn .i had my air cleaner cause me a similar problem i installed one that draws through the top . that helped also raised apt 1 turn and fixed my problem both helped . may not fix your problem but easy to do. fwiw