gmc problem

[Christopher Comeaux]

i have a 2004 gmc yukon xl 5.3 254000 miles and the fuel pump relay is melting burning up. anyone have any ideas whats going on. i replaced the motor with a used one at 248000 and this issue is coming up

 

[Bob McDonald]

My first question is: Where is the fuel pump on the Yukon? On the motor? In the tank (like on the Trac)?



If it is in the tank, probably not related to the engine swap unless a fuel pressure sensor at the engine is signaling low pressure and the pump keeps running trying to increase the pressure.



Also, if in the tank, tank may have been too low on fuel to help keep the pump cool.



Just a couple of thoughts when there is a lack of a lot of evidence.

 

[Christopher Comeaux]

its in the tank. tank is full. just relay is getting hot. the other day it melted/burnt. it runs great just gets hot

 

[Bob McDonald]

Oops, My bad. You did say relay.

Where is the relay mounted? Is it in a quick remove socket? Any chance that the wrong relay part was installed (one not rated for continuous use)?

 

[scott degroot]

I would first check the ground for the fuel pump itself, I believe it is located by the left rear tire on top of the frame rail. Make sure your other gorunds are ok as well. In order for the relay to be getting hot it has to be running alot of current though it...obviously. Have the amperage through the relay measured.