2011 Ram 1500 32000 mi on rebuilt motor.
Just had fuse box replaced. Truck will not immediately start. Can’t hear fuel pump engage when key is switched to on position, but after cycling switch on ad off several times the truck starts and runs fine. It’s only after it’s sat for over an hour or so that it will not restart and I have to repeat the on off key cycling to get it to start.
I’ve checked all fuses and relays and they checked out good. No CEL. I am using quite a bit more gas than usual. I considered the fuel rail sensor as the problem, but would like a more professional opinion…any suggestions??

 

Think I would put a gauge on it, and see how the pump behaves on a cold start.

 

Agreed, checking the fuel pressure would be a good place to start. Did this issue start immediately after the fuse box was replaced? By "fuse box" are you referring to the Totally Integrated Power Module (TIPM)? Around that model year, there was a known TIPM issue with fuel pump relays. If your fuel rail pressure is low, I'd also suggest you confirm whether or not your fuel pump is getting full battery voltage to prime the system. I don't recall if the 2011 have a serviceable fuel filter or if it's only part of the fuel pump assembly, but if serviceable, replace the fuel filter too. If the issue ends up being a weak/failing fuel pump you'll want to have a new filter anyway.

-Rod

 

[QUOTE=SHO Rod;3603399]Agreed, checking the fuel pressure would be a good place to start. Did this issue start immediately after the fuse box was replaced? By "fuse box" are you referring to the Totally Integrated Power Module (TIPM)? Around that model year, there was a known TIPM issue with fuel pump relays. If your fuel rail pressure is low, I'd also suggest you confirm whether or not your fuel pump is getting full battery voltage to prime the system. I don't recall if the 2011 have a serviceable fuel filter or if it's only part of the fuel pump assembly, but if serviceable, replace the fuel filter too. If the issue ends up being a weak/failing fuel pump you'll want to have a new filter anyway.

The issue only appears to have gotten worse after the replacement. Went from bad to very poor gas mileage. I’ll check the voltage at the pump to make sure it’s correct. There apparently was a jumper wire in the fuse box that had something to do with the fuel pump that overheated caught fire and damaged the entire box

 

That sounds like the fuel pump bypass for a failing TIPM.

-Rod

 

So would you say that the fuel pump was possibly defective initially the reason that a fuel pump bypass jumper was placed in the fuse box in the first place?

 

Not the pump, the relay. A known problem on some years.