Hey everyone, looking for some help diagnosing an issue on my 1998 Wrangler TJ (4.0L, automatic). I recently replaced my fuel pump with a brand-new Delphi FG1353 module. The pump has less than 100 miles on it, hasn’t even made it through a full tank yet, and I’m already running into problems.
I originally replaced it because I thought my old pump wasn’t holding pressure (hard crank with no fuel). The new one seemed fine at first, but now I’m getting intermittent fuel pressure issues and some new symptoms as well.
What’s happening:
When I installed the Delphi FG1353, I struggled with getting the pump module and the rubber gasket/o-ring seated correctly. I eventually got it to look right and the locking ring went on, but it took some work and I wasn’t 100% confident during the process. The gasket looked properly seated when I finished — just mentioning this in case a slightly misaligned seal could cause intermittent pressure loss or the pump picking up air under certain conditions.
Before I drop the tank again or return the pump, I wanted to see if anyone else has experienced similar issues with the Delphi FG1353 on a TJ, or if a tricky gasket/seal could actually cause these symptoms even if it appeared correct.
I only replaced the module due to the hard crank/fuel pressure issue originally. Fuel pressure checks out every other time, and with this new pump as well. I have not been able to catch it when it doesnt have pressure/hard cranks though.
I originally replaced it because I thought my old pump wasn’t holding pressure (hard crank with no fuel). The new one seemed fine at first, but now I’m getting intermittent fuel pressure issues and some new symptoms as well.
What’s happening:
- Occasionally after the Jeep sits (really it could be 5 minutes or overnight), it will not build fuel pressure on the first start attempt.
- It just cranks with no fuel until I cycle the key again to prime the system.
- After priming, it starts instantly.
- This does not happen every time, only randomly.
- While driving, the Jeep will sometimes feel like it’s not getting fuel at all.
- Idle will suddenly drop extremely low and the engine struggles for about 15–20 seconds.
- During this, the gas pedal does nothing — no response at all.
- After that, it suddenly recovers and drives normally again.
- It has never fully stalled, but it feels close.
When I installed the Delphi FG1353, I struggled with getting the pump module and the rubber gasket/o-ring seated correctly. I eventually got it to look right and the locking ring went on, but it took some work and I wasn’t 100% confident during the process. The gasket looked properly seated when I finished — just mentioning this in case a slightly misaligned seal could cause intermittent pressure loss or the pump picking up air under certain conditions.
Before I drop the tank again or return the pump, I wanted to see if anyone else has experienced similar issues with the Delphi FG1353 on a TJ, or if a tricky gasket/seal could actually cause these symptoms even if it appeared correct.
I only replaced the module due to the hard crank/fuel pressure issue originally. Fuel pressure checks out every other time, and with this new pump as well. I have not been able to catch it when it doesnt have pressure/hard cranks though.
