LR4 Fuel Issues after alternator fail

[jlglr4]

Possibly the fuel pump relay?

 

[itsaguything]

Could be…. but pinpoint test #1 still needs to be passed.
I can’t imagine “tinkering” without the workshop manual. If you send me a PM…

 

[Mitchel3408]

Possibly the fuel pump relay?

I was thinking about that. I think I saw the relay is behind a panel at the back seats. This weekend I’m going to dive back into it.

 

[Mitchel3408]

I went to the store this morning and tested the battery, it passed but was near end of life. The manager warrantied it out for a new one. I put it in and cracked for about 15 seconds before it fired off. Idled for about 10 minutes and watched the fuel pressure which was close to 500 at idle and 900 psi at 3000 RPM in park. I shut it off and cleared existing codes, then started it back up. It died about 30 seconds later, and then just cracked when I tried to restart it. So the alternator and battery are both new at this point and I need to start running down the fuel system.

 

[Mitchel3408]

I tested the fuel pump relay and it’s fine, I swapped it with the AC relay to double check and truck still wouldn’t start. I jumped the relay terminals to listen for the fuel pump running, didn’t hear anything.

I’m not sure how the wiring on this system is set up but wouldn’t that point to a bad low pressure fuel pump? Or is the power to the pump controlled post relay by the fuel control module?

 

[jlglr4]

sounds like the lp fuel pump. i think the old test was to turn your ignition on and of several time (turn on for 10 seconds or so, then off, then on for another 10 seconds or so, etc) to try to get the pump to build up some pressure. if that helped to get it started, but would then quit, it pointed to a failing pump. No idea if it works. Of course, if the pump has quit entirely, it won’t do anything.

 

[itsaguything]

check your email @Mitchel3408

 

[Mitchel3408]

Update: So I finally got all the parts in after several shipping issues. New low pressure fuel pump and filter installed. Car runs great now.

Only problem now is the fuel gauge. When I started it up it was stuck on empty. Pulled the battery the next day and it was reading fuel but was slightly off. Filled up once and it read 3/4 full. Filled up again after using 10 gallons and the fuel gauge now reads 1/2 full.

Is there any kind of relearn procedure I need to do? Or is it just an issue with the wiring/float? The new pump didn’t come with a float so I transferred the old one.

 

[itsaguything]

Or…your tubing or wiring is interfering with the float??

 

[Mitchel3408]

Or…your tubing or wiring is interfering

Possibly. I made sure the float had full range of motion and nothing was close to it but it’s hard to say what moved when I put the cap/filter into place. I might run it low on gas and scope it to see if anything is in the way.