2000 4.0 Fuel Pressure Question

[MayzesTJ]

Hello,
When turning my key on. Pressure primes to 50, then after a few seconds drops to practically 0. Fuel pressure should hold for a few minutes around 50 correct? When running it’s 45-50 no issue. Any suggestions

 

[roboto65]

Yeah that's not good the most common causes include a leaking fuel pressure regulator, a faulty check valve in the fuel pump, or leaking injectors.

 

[TJ4Jim]

Hello,
When turning my key on. Pressure primes to 50, then after a few seconds drops to practically 0. Fuel pressure should hold for a few minutes around 50 correct? When running it’s 45-50 no issue. Any suggestions

Are you having starting issues.

 

[macleanflood]

You can just replace the pressure regulator on top of your fuel pump assembly.

V

Thread 'How to replace your fuel pump without replacing the whole assembly'

Dec 21, 2021

Ok, I figured I'd post this here since I haven't seen it anywhere else. I've been chasing a hard start issue on my tj and got down to the in tank pump. I knew the sending unit was still good, but wanted the peace of mind of having a new pressure regulator and pump. I also didn't want to fork over ~$200 for a new assembly when I knew I could find a pump and regulator for much less. I didn't take pictures during the process because I'm a dumba$$ and this was the last thing I did on a Saturday so I was ready to be done. This only applies for 97-04 TJ's I believe. Assuming you've managed to...

• vrtillman
• Replies: 21
• Forum: TJ How-to Guides

• 

-Mac

 

[MayzesTJ]

Are you having starting issues.

Past few times it took a minute to start.

 

[TJ4Jim]

Past few times it took a minute to start.

Ok so there may be a bleedoff issue, just asking as no pressure doesn't create an issue unless all the fuel draind out too. As macleanflood suggested the regulator (most common) can be replaced on it's own.