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post #1 of (permalink) Old 05-31-2002, 12:33 AM
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It is a Jeep....question!!!

Hello ,

I am going to try to give you as much details as I can so you may help me. My Jeep is a 1989 YJ with an AMC 258 engine, it has a Clifford intake, a 390CFM Holley carb with the John Nutter by-pass done on it. I have a Mallory electric fuel pump and fuel regulator. I have a complete Borla exhaust system. My ignition is a Jacob omni torquer and a Mallory Unilite distributor.

So, here is the problem. Every time I begin to drive on a bumpy road my Jeep begins to run rough and stall (not very funny for a 4WD car!!!). It happens in 2H, 4H and 4L drive (it is a MT 5 gears)...When I stop before it stall the engine begins to idle well, if it stalled and I restart it, it is a long cranking and it start and smell gas a lot...

So, as far I have checked my carburetor float level, and try to figure out if it could be an electrical problem (electric fuel pump), I put the Jacob off but it didn't change anything...

What do you think I should do, I am lost, the funny part is that on road it runs very, very good!!!

Thanks a lot


Ps, I am french so I hope my english isn't to bad and you will understand what I wrote ;-) .....
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post #2 of (permalink) Old 05-31-2002, 02:28 AM
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Re: It is a Jeep....question!!!

Hi FrenchJeeper,

Another French Jeeper here ! I am located near Bordeaux and I guess I saw your rig on Jeepmania or something. Am I right ?
Anyway welcome on this board, you will see that people here are very very helpful.
I have no clue of what can cause your problem so I will let more knowledgeable peolpe help you out !
Take care
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post #3 of (permalink) Old 05-31-2002, 03:33 AM
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Re: It is a Jeep....question!!!

Start with this,

If the float level is set so the fuel just creeps into the threads of the sight plug, then lower your float level two flats on the adjuster nut.

Use the 'Off Road' spring loaded needle and seat from Holley. The aftermarket sets are unacceptable.

Use a piece of tubing or an old 90 degree spark plug boot to raise the float bowl vent up higher.

Make sure there is at least 1 inch (3 is much better) between the float bowl vent and the top of the air cleaner.

On top of all this, side pivot float bowl (you may already have this) uses a mostly round float, and this takes bouncing better than the square ones in the center pivot bowls.

If you have a center pivot bowl, use the Nitrile float kit and install the jet extensions.
Cut the ends off the float and seal the foam with a fuel proof epoxy.

If you want specific information, I'll need the 'List' number off the front of the choke air horn.

You may also check to see if the 'Shutter' (rotor replacement) in that Uni-Lite is loose or moving around.
Any movement, and that thing will leave you walking home.

You didn't say, but if you have the Jacobs coil, you may have beat the guts loose in the coil. They are known for failure.
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post #4 of (permalink) Old 05-31-2002, 08:39 PM
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Re: It is a Jeep....question!!!

Is it possible that you have some debris in the tank that's getting stirred up on the bumby road and plugging the fuel pickup?
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