Fuel Pump Issues

[Damien89]

Guys, I really need your help. My fuel pump is not turning on. I have replaced the fuel pump, the relay, and the fuse associated with it. I'm lost! I have a 1994 Infinti q45 (My Baby).

[BCC93QT]

By "relay" you mean the Fuel Pump Control Unit (FPCU)?? What kind of pump is the replacement?

[OwnerCS]

If you can provide a sequence of events up to the point where the failure occurred it will help us diagnose.

Also, miles and any fuel system maintenance history help.

[Damien89]

I replaced the lime green relay located in the right rear of the trunk. The events leading up to this we're as follows:

Thursday, began to put a little while leaving the grocery to store. Then it cut off. The fuel pump wasn't on then (I notice after multiple attempts to crank it). I call the tow truck, and about 45 min it fired up as if nothing odd had just happened.

Friday, drove to work and back with no problem.

Monday, the same is true

Tuesday, when u went to crank it(before work) nothing. The same thing when I realized that the fuel pump wasn't on initially.

[goody90q45]

Sounds like your fuel pump control unit may have a melted solder joint. It's a common problem with the G50 if your fuel pump was going bad which would cause a high amp draw to the FPCU. Was the fuel pump humming like a swarm of bees prior to the no start issue? Since you've put in a new fuel pump it will be easy to check by unplugging the FPCU and jumpering the connector to ground. The FPCU is under the rear deck in the trunk. You can see it in the background in the picture. Reach in and unplug the connector, run a jumper from the pin shown to ground (unpainted metal frame aft of the fuel tank works well) and see if it starts. If the engine starts the FPCU is bad but repair of the FPCU is an easy solder job. See if this works and we'll talk about FPCU repair next.

[Damien89]

I apologize for the delay. Thank you all very much for helping me solve this problem. I ran the test and sure enough, it was the fPCU. My uncle made the comment, "that didn't cross my mind." Once I informed of this. We replaced it and my girl is now back on the streets. I'm overly satisfied. Thanks again!

[Q451990]

Tell your uncle to not feel bad about not thinking about the FPCU. Most cars don't have them.

Heath