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Old 10-01-2009, 11:35 AM   #1
britcay's Avatar
Join Date: Sep 2009
Location: Grand Cayman, Cayman Islands
Posts: 26
Idle/Cut out - A/C causes stalling or rise in idle speed

I have an idling issue....

Periodically I get a stall at idle, or even downshifting esp without the a/c on. Seems worse once the Jeep is warmed up.

I noticed if I turned on the a/c then the idle speed increases a couple of hundred or so, not huge. Sometimes it'll drop down (dont think it's sticking as I've tried blipping the throttle nothing happens) then up... then down.... no discernable pattern.

So I started to check for vaccum leaks and noticed at first one tube just hanging at the rear of the carb - I traced this to the front of the air intake (before filter, manual says "reverse delay valve" what is that, some kind of warm air valve??).

Second and with the engine almost dying, I noticed another tube exiting the rear of the carb, going into a small diaphragm with a moving needle behind. When I removed this, the needle sat back, the engine idle jumped back to normal and the carb sucked in air thru this, but all seemed to work fine.

What (aside from unfiltered air in the carb) am I damaging by running like this? The engine has been idling and running perfectly since.

I'm thinking of doing the nutter bypass as I suspect some shenannigans with the computer etc, but any ideas welcomed on that vaccum pipe?
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Old 10-01-2009, 02:46 PM   #2
Join Date: Nov 2008
Location: Louisiana
Posts: 29
I think you should be fine. can you get pics of the line in question?

1992 YJ 6 1/2" Lift SOA , Rear Dana 44 with Detroit Electrac out of 1987 XJ, 1995 XJ Dana 30 with ARB and 4:56 gears,JB4x4 High Steer, 33" super swampers. 1995 XJ 4.0, Ax-15 trans, Dana 300 Twin stick flipped w/ northwestfab cable shifters.
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Old 10-03-2009, 11:33 AM   #3
britcay's Avatar
Join Date: Sep 2009
Location: Grand Cayman, Cayman Islands
Posts: 26
Ok Red, here it is.... my hand is getting in the way a bit, but I'm holding the tube away from the back of the carb - the valve with the moving needle can just be seen above this

any ideas welcomed
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