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Unread 01-18-2010, 04:29 PM   #1
boomvader
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Bad TBI electronic fuel pump or problem with fuel tank?

I recently purchased a 1985 CJ-7 with an analog Holley Pro-Jection TBI system. It had been sitting for about a year in a garage before I purchased it. It had about an 1/8th of a tank of fuel at the time. I did not drain the tank. Instead, I filled it up with fresh gas. The tank is the 20 gallon optional plastic tank. I also live in Arizona where there is not much issue with rust.

My problem started last weekend when driving it home from a quick 20 mile trip. It started to act as if the engine was running out of gas. I barely made it home. Once home, I could no longer start it. A quick look underneath exposed an issue with the electric fuel pump mounted on the inside of the rear crossmember of the frame in front of the fuel tank. The pump appeared to be leaking. The pump looked old, so I ordered a new pump, both fuel filters, and new hose. Once I replaced everything, it still would not start. I checked the both ends of the pump at each filter and they were BOTH dry. I was able to hook up a hose and blow air into the fuel line going into the tank and I heard the sound of bubbles. I also added 5 gallons of fresh fuel in case the fuel guage was off and I was low on fuel. This did not help.

I am at a loss as to my next move in troubleshooting this issue. The pump does turn on when I turn the key to the RUN position, but stops after about 5 seconds. I have attempted to 'prime' the system by continuously turning the key on and off to no avail. No fuel is getting to the pump.

I am not sure whether I have a bad pump or not based on its behavior. Does this sound normal? Am I leaving out a step for properly installing the new electric fuel pump and filters? Both filters are exact replacements. The pump is a Walbro.

Any insight on this would be greatly appreciated.

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Unread 01-18-2010, 04:32 PM   #2
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Also, I have verified that the pump and both filters are facing the correct direction.
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Unread 01-18-2010, 05:03 PM   #3
gmakra
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Take the supply hose off the carb and insert it into a container turn on the key to prime the pump, when you get a good stream reattach the hose and start the Jeep.
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Unread 01-18-2010, 05:08 PM   #4
boomvader
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The problem is I cannot seem to make the pump stay on long enough to pull any fuel. Does removing the supply hose help the system by relieving pressure?

Thanks for you reply!
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Unread 01-18-2010, 06:17 PM   #5
gmakra
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If the pump starts then shuts off it maybe a software issue in the Pro-Jection system. Call tech support for them and see what they say.
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Unread 01-18-2010, 10:26 PM   #6
bubba+78363
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The pump is supposed to only run momentarily when you first turn the key to the start position. It just builds up the pressure in the sytem, and will not run again until the engine has started. The original pump with the system was designed to push fuel and not suck and this was why it needed to be mounted below the lowest point of the tank. Not real sure about your new pump. If you hear the pump running, but nothings coming out of it you might have to drop your tank and take a look inside of it. You said it had been sitting awhile before you drove off in it. DId you get the install manual for that system when you bought the jeep?
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