I would like to say first, I did not find anything using the search function. My Jeep started to have issues starting about 3 weeks ago. Today I threw on a Fuel Pressure Regulator and it read 40 while the switch was on and while the motor was running. When I killed the motor, the pressure dropped to about 20 after 3 minutes of the jeep being off. I have a new Fuel pump to install, but my buddy said it also maybe a bad injector leaking fuel or getting stuck open, and pressure is not being retained. Anyone have any ideas or pointers they can give me?

Thanks
Chris
98 XJ Classic

 

When you start it, does it start rough then even out after a few seconds? Or does it start easily after primed?

 

It idles a tad rough, the Tach seems to jump a little at idle, so does my oil pressure gauge.

 

Have to find a way to separate the test between the injectors and the tank. I couldn't figure out how to do it on the 98 so I just used it as an excuse to upgrade to the four-hole injectors It wasn't the injectors...
I can hear a gurgle in the tank when I shut it off which I assume is the fuel bleeding back into the tank.
A bad check valve you can deal with, leaky injectors are very dangerous. As one member puts it: Leak, spark, fire, the plastic clips on the hood release melt, you can't open your hood even if you had fire extinguisher and your Jeep is toast before you can dial the fire department.

 

Even if you had a bad injector, the pump should be able to maintain 49 PSI when running

 

I agree with Cruiser. The fuel pressure spec for the 98 is 49 psi, plus or minus 5 psi.

40 psi when running is out of spec. You could slap on another fuel pressure gauge to verify your prior fuel pressure readings if you wish, but if that reads the same, you need to replace your fuel pressure assembly.

Do NOT install an Airtex or any other fuel pump hardware rebranded by Airtex. Search this forum and any other Jeep Cherokee forums to understand why.

Good luck and keep us posted!