Fuel Pump Issues

rockytriton

New Member
Joined
Apr 10, 2024
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Location
Omaha, NE
Hi all, I have a 1999 4.0L. So I had issues with long crank time, I pump a fuel pressure gauge on it and I could see that after a couple key primes it would get up to 40 psi and then slowly go down. So assuming that means my fuel pressure regulator is bad. So I went to Oreilly and bought a new fuel pump assembly. It was about 150 bucks.

I went through the whole process of changing it out and everything was great for about a week. Then it started making a high pitch noise one day, constant high pitch noise, then the next day it wouldn't start at all and couldn't get any pressure. Fortunately I saved my old fuel pump assembly. Put it back in and it works ok again, but still has the issue with losing pressure when off.

So my question is, maybe that new pump was just bad? Can I get a better quality one? If so, which would you recommend? I want one that will be reliable and not die in a week out of the blue again. I assume that they don't make the same one anymore? Is it possible to just get the regulator part of it and keep the current assembly? I'm not sure where to find all of these things and would like to avoid Oreilly again.
 
Hi all, I have a 1999 4.0L. So I had issues with long crank time, I pump a fuel pressure gauge on it and I could see that after a couple key primes it would get up to 40 psi and then slowly go down. So assuming that means my fuel pressure regulator is bad. So I went to Oreilly and bought a new fuel pump assembly. It was about 150 bucks.

I went through the whole process of changing it out and everything was great for about a week. Then it started making a high pitch noise one day, constant high pitch noise, then the next day it wouldn't start at all and couldn't get any pressure. Fortunately I saved my old fuel pump assembly. Put it back in and it works ok again, but still has the issue with losing pressure when off.

So my question is, maybe that new pump was just bad? Can I get a better quality one? If so, which would you recommend? I want one that will be reliable and not die in a week out of the blue again. I assume that they don't make the same one anymore? Is it possible to just get the regulator part of it and keep the current assembly? I'm not sure where to find all of these things and would like to avoid Oreilly again.

Yes, your new pump is bad if your original issue stayed the same and operation stayed the same with the OEM pump. You CAN replace the regulator (technically the check valve too which is what your issue is).

I have an O'Reilly pump in mine currently. Either way, If the pump is old enough to require a check valve, I'd rather just put another QUALITY pump in.
 
I threw a BrutePower pump in my 97. I figured if I was going cheap then I'm going all in. $58 and $15 in shipping from Rock Auto. Allegedly designed in the USA. Been running 2-3 weeks no issues.

YMMV.

-Mac
 
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I've often wondered if splicing in an additional electric pump between the tank and the intake would help, so long as the original pump is providing ANY pressure, the secondary pump should 'kick in' and keep the pressure up.
At least, that's my theory.
 
I picked up a cheapo ZJ from a friend. The FP whined like all get out. he also gave me a new from Oreileys FP assembly. Swapped them and it was just as loud. I dont know what he paid for the FP, but I did some digging and found what looked identical for around $70. I later looked up the pump on Oreallys and IIRC it was $200 or so.