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Discussion Starter #1
Hello guys! I have a 98 Tj 4.0L 5 speed with 147XXX. I bought it with somewhere around 135xxx.

The Problems;
After having it less for 2 days I had to replace the fuel pump. It was cutting in and out. I replaced it with an Airtrex fuel pump from advance auto. Of I course have the 15 gallon tank. Since then I have been threw 3 fuel pump including the one that just went today. At the time of the engine just shutting off I have no fuel pressure at the fuel rail. This is each and every time.

So I have checked fuse and replace the relay. My problem is I just can't figure out why I only get a few months out of it and only 2k if that. They don't totally seem to die but go out here and there till I can't rely on the jeep.

Does anyone know the difference in the 15 to 19 gallon units. Wondering if I end up with a 19 gallon unit in a 15 gallon tank?

Any other ideas why I'm going threw them would be great. I'm gonna try to test power at the plug the next time it mess up.

Thanks Doug.
 

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Airtex fuel pumps are as cheap as they come, despite the 'lifetime warranty' some stores include with them. I wouldn't trust an Airtex in my TJ. For critical parts like that, I'd stick with better quality like the OE Mopar fuel pump. You've installed three cheap fuel pumps, was that cheaper price worth it? No, of course not. I'd lick my wounds, try to get a refund, & go buy a Mopar fuel pump. Sure it's more $$$... how many more times do you want to have to drop the gas tank to replace it?

15 gallon tanks are pretty rare in Sport TJs, it'd have to be a very stripped down version to not have the 19 gallon tank. Some think they have a 15 gallon because the gas gauge is so inaccurate, it commonly indicates the tank to be empty when it often really has 4-6 gallons left.
 

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Also, try your best to keep at least a quarter tank full of gas at all times. You may already be doing this, but figured I'd throw it out there. There's no cooling system for the fuel pump besides the gas itself, and running it low can cause the fuel pump to burn up. Especially when running a low quality Airtex, as Jerry aforementioned, it's a recipe for failure.
 

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Discussion Starter #4
Thank you guys. I was gonna look into a bosh pump next. I happen to run the jeep to the low fuel came on. With low fuel light on I have only ever put 13 or 14 gallons in it. That made me think it was a 14 gallon tank. Is there a way to tell?
 

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Requesting a build sheet from Jeep isn't a bad idea. It'll help with future reference as well.
 

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Thank you guys. I was gonna look into a bosh pump next. I happen to run the jeep to the low fuel came on. With low fuel light on I have only ever put 13 or 14 gallons in it. That made me think it was a 14 gallon tank. Is there a way to tell?
Bosch makes the OEM pump.
 

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Also, try your best to keep at least a quarter tank full of gas at all times. You may already be doing this, but figured I'd throw it out there. There's no cooling system for the fuel pump besides the gas itself, and running it low can cause the fuel pump to burn up.
The fuel pump is not splash cooled by fuel in the tank, it is cooled by fuel passing through it internally as it pumps fuel. So long as the fuel pump is pumping fuel, it will run cool. In the event of an empty fuel tank, the engine dies and the ECM then shuts off the fuel pump... it will not continue to run if you run out of gas. :)
 

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The fuel pump is not splash cooled by fuel in the tank, it is cooled by fuel passing through it internally as it pumps fuel. So long as the fuel pump is pumping fuel, it will run cool. In the event of an empty fuel tank, the engine dies and the ECM then shuts off the fuel pump... it will not continue to run if you run out of gas. :)
My mistake. Thanks for the correction. :thumb:
 

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The Jeep can't "over power" the fuel pump... it provides 12 volts to the fuel pump as required, that is it. Did you read post #2 above?
 

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The fuel pump is not splash cooled by fuel in the tank, it is cooled by fuel passing through it internally as it pumps fuel. So long as the fuel pump is pumping fuel, it will run cool. In the event of an empty fuel tank, the engine dies and the ECM then shuts off the fuel pump... it will not continue to run if you run out of gas. :)
The pump also has a sump in it which prevents fuel starvation around corners, and also keeps the pump submerged in fuel.
 

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As Jerry noted Airtrex is about as cheap as it gets but on the off chance your failure is not due to the quality of the replacement, I would suggest checking the power wiring for the fuel pump for corrosion, chafing, etc.

An electric motor will pull the power it requires via voltage or amperage. What this means is if, due to corrosion or other line losses, you are getting a voltage drop at the pump motor, the amperage will go up... and up... and up until the fuse blows, wire melts or the motor overheats and fails.

Ideally, you would want to check the voltage at the tank terminals when the pump is running but that can be a challenge in a jeep. At least, when you're doing your next replacement, once the power wire to the pump is disconnected, use a VOM between the power lead and a GOOD ground and have someone turn the key to "run"... do not crank! See if the voltage when the key is in "run" is within 2% to 3 % of what you read between the battery terminals. If it's much less, go hunting for the loss.

I have seen wires get chaffed at body penetrations, not enough to short, but allowing water, salts and dirt to get to the conductors and turn the wire to a mass of green goo. BTW, green goo does NOT conduct electricity very well....

Have fun.....
 

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Some one may have put a cut out switch (security/theft deterent). that could cause resistance loose /dirty/pitted contacts. I did not know the Airtex unit was low quality. I am going to have to replace my sending unit/pump, so I am glad I didnot buy one yet. I read ChaddG says the spectra premium is the best-maybe bosch next? what do these better units cost?
 
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