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Air cleaner causing car to stall?

1648 Views 9 Replies 6 Participants Last post by  Ricks73
I recently had my car out and noticed that since i installed a k&n 14 x 4 with extreme lid that the car wants to stall when coming to a stop. i have to either feather it or go to neutral but even then still wants to stall. The only adjustment i ever did to the carb since i got it back from the builder who dynoed it was giving the 4 corner idle screws 1/4 turn counterclockwise (richen it) because i had the same prob when i didn't have a air filterr , the engine wanted to stall in gear. Wondering if I should turn each idle mix screw in (lean) 1/4 and go back to the baseline. OR maybe take the air cleaner off first and tke the car for a ride and see what happens? ANy fthoughts would be great. By adding a air filter are you supposed to adjust the carb? BTW im running a pump gas 496 with a 950 holley :confused:
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Stalling while on the brakes is always your float level being too low.

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thanks for the replies

any other suggest?
I ran into the same problem just last month after I properly set my idle mixture screws and then messed with them afterwards. I had them set by highest vacuum reading, but then after tinkering with the carb more, I threw them out of wack and never verified them again. The result was when the car warmed up, sometimes at a light it would stall. Put it into park, it'd fire right up, and put it in gear and it'd be fine.

I checked my screws, they were only 1.5 turns out, too lean. So I turned them both 1/2 turn out to 2 turns out, no problems since then. This weekend I may try to set them properly again with my vacuum gauge.

Just sounds like your idle is overly lean/rich and needs to be set properly with a vacuum gauge for highest vacuum reading. I think if you do that you'll be good. If it still stalls after that, you must have another problem elsewhere (float level issue, vacuum leak, etc).

Let us know how it works out!

Thanks carl for the help. I haven't been able to mess with the car. When I do I will be sure to have a vac gauge and get a reading as it sits, then turn the screws in 1/4 to see if the gauge rises. All in all it sounds like that just by adding an air filter to the carb doesn't necessarly mean that the carb has to be adjusted, right?
Also get tach,dwell meter or something to check the idle rpms. RICK
You wouldn't think so, but if your carb was borderline lean/rich before at idle and you tossed on an air cleaner it might have been enough to throw it off, who knows.

I often read into things too much and overanalyze stuff when something is wrong with my car. Usually the simplest explanation is the correct one. So I look things up online and read about stuff. Then I get home, do the simplest thing to fix it, and then it works fine. Haha!

So while you wouldn't think an air cleaner would throw things off that much, who knows, every car acts differently. Your best bet is to just use the process of elimination, ensure your idle mixture is set correctly, ensure your timing is up to par (enough initial for your cam/setup), ensure your idle speed is appropriate (without transfer slots showing, etc), and you should be good to go.
Air Cleaner causes stalling

I recently installed a broadband O2 meter on my car and one of the instructions says to adjust the idle mixture with the air cleaner on the car if possible since it will change once you put the air cleaner back on.
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