Novak Conversions Jeep Wrangler TJ radiator

Is my fuel pump bad?

PWMJeep

PWMJeep

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Original poster
Joined
Nov 4, 2018
Messages
28
Location
Portland, Oregon
So I have been having some issues with my 1998 Jeep TJ 4.0 not wanting to start when hot, and twice it's died at stoplights after getting up to temp. I just tested the fuel pressure at the Schrader valve with an O'Reilly's auto parts loaner gauge. Maybe I didn't do it correctly, but I simply hooked up the hose and turned the key to the run position. The gauge went from zero to 20 psi. Should I have cranked it or is this enough info to verify that I possibly have a bad fuel pump?

Thanks
 
When you turn the ignition to RUN the fuel pump should run for 3-5 seconds and stop; the pressure should increase to at least 49 psi.
Ensure the fuel pump actually starts; 20 psi could just be residual pressure after the pump has stopped.
Verify the fuel pump relay CLICKs when the ignition is turned to RUN.
IF the fuel pump does start, but stops running when the engine is being cranked; check the fuel pump relay as described below.
Remove the fuel pump relay and test resistance across terminals 85 & 86; IF the resistance is more than 70 ohms you need to replace the relay.
When the magnetic coil windings resistance get too high; the voltage creating the magnet will not be enough to hold the contacts closed for running the pump.
 
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I guess that I should clarify, I released the pressure at the valve, hooked up the gauge which read zero psi. Placed the gauge on the windshield and got in the Jeep. I turned the key to run, but did not crank and heard the pump kick on. The gauge went to 20 psi. It has a new fuel relay as well. Sounds like the pump is done to me.
Thanks
 
No leaks, no gas smell. My bet is on the pump. I'd like to replace the whole module that also has the regulator. I can't find an OEM one or one labeled as Bosch. Recommendations?

Thanks, Patrick
 
PWMJeep said:
No leaks, no gas smell. My bet is on the pump. I'd like to replace the whole module that also has the regulator. I can't find an OEM one or one labeled as Bosch. Recommendations?

Thanks, Patrick
Click to expand...

Good luck finding a bosch. Not impossible but difficult. I went with a Delphi fuel pump about 2yrs ago and have been fine.
 
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Hopper said:
Good luck finding a bosch. Not impossible but difficult. I went with a Delphi fuel pump about 2yrs ago and have been fine.
Click to expand...

I was looking to buy, Delphi FG1353 Fuel Module on Amazon, but it states that it doesn't fit my 1998 Wrangler. Can anyone confirm what part # I need?

Thanks

​

 
PWMJeep said:
I was looking to buy, Delphi FG1353 Fuel Module on Amazon, but it states that it doesn't fit my 1998 Wrangler. Can anyone confirm what part # I need?

Thanks

​

Click to expand...

Amazon does that alot but some will chime in soon hopefully to confirm. Mine is a 99. I have an extra one in the basement I will check part# if I can uncover it.
 
20220727_141642.jpg
 
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Hopper said:
Good luck finding a Bosch. Not impossible but difficult. I
Click to expand...
Sourcing Bosch fuel pumps has been hit and miss.
A couple months back a source became available for Bosch fuel pumps and I purchased one that I stored with other spare parts I have been accumulating.
My thoughts are.... even if you don't need the part presently; purchase a spare for the future.
 
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