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Hello all.

Two weeks ago I replaced my fuel pump and everything went smoothly. Approximately four days later my car would not start and I was not getting any fuel or pressure to the rail.

I then dropped the tank again and found that the three inch piece of high pressure hose that connects the top of the fuel pump to the sending unit had began to tear. I also noticed that the sending unit seemed slightly bent but I didn't think much of it at the time.

I replaced the three inch hose, put the tank back up and everything seemed to be back to normal. Running strong and smooth. Two days later my jeep would not start again. I had the same symptoms as before, no pressure or fuel to the rail.

So today I dropped the tank again and this time I noticed that the tank looks like its collapsing and the sending unit was noticeably bent and contorted. I bent the sending unit back into shape and replaced the small hose once more. I also tested the pump and unit before placing it back in the tank. Everything worked perfectly until I put the sending unit into the tank. For some reason once I get the sending unit into the tank and the tank jacked up with all of the vacuum lines and hoses connected the pump will not turn on. I checked this twice and dropping a tank two times in one night is too many.

So I'm looking for any reasons or ideas of

1. Why is my tank contorting and bending the sending unit? This is causing the three inch hose from pump to sending unit to tear repeatedly. Can this be dangerous?

2. Why would my fuel pump not engage only when in the fuel tank ?

3. At the end of the sending unit there's a small rubber grommet that I believe fits onto the end of the return line. I lost this and don't know if its of any significance. Anyone know?

Any ideas or advice would be much appreciated.
 

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Plastic or metal tank? When the fuel is removed by the pump there is a little pressure built up but the vent/rollover valve should relive this along with the vented fuel cap. The rest of the problem baffles me also.
 

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I've been working with Kevin on this...
its a plastic tank.
Today I dropped the tank again and put in a new fuel pump and pump relay. The pump works great ((meaning we hear the pump engage, and see gas pumped...we tested this in a can) out of the tank plugged into the harness but as mentioned in the earlier post once its mounted into the tank, we hear nothing at all coming from the pump...no humming to let us know the pump is priming.

I guess I will drop it one more time and verify all the wires are correct but I am 99.9% sure that they are particularly since it works outside of the tank.

Any help is greatly appreciated.
 

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We decided to check all of the connections on the new fuel pump again and all looked good. As a last resort we then decided to change out the terminal connector on the neg. battery terminal since it didn't seem like it was tightening snugly. Once we did that the pump worked and the Jeep fired up.

However now I hear a loud whining noise coming from the rear when the jeep is running. It sounds like its the fuel pump...
Could it just be an extremely noisy pump? I've never heard anything like this before.

Anyone have any idea's?

Thanks
 

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Ok, this might sound strange, but did you by chance put the plug that attaches to the fuel pump at the back on backwards??? 180deg...
The fuel pump sounds like it is constantly working, wich would mean that you have a fuel leak,fully open injectors, something that is causing it to stay on...it is an on demand pump...
also check the rollover vent. and lines going to the evap canister, could be cloged...Wait... did you use submersible fuel line???
here is another dumb question,
fuel lines on backwards... this could cause the tank to suck up into itself..

fuel filter on backwards, flow in the wrong direction...

Ok.. I am now officialy out of ideas....
 
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