fuel pump relay 98 5.7

[wkobe88822]

Does the fuel pump always run off the relay or only while the 2 second system prime? My truck will run without the relay.

 

[kennythewelder]

Long but good video.

xc_hide_links_from_guests_guests_error_hide_media

 

[Schurkey]

If it's anything like the earlier GM vehicles, the fuel pump relay is bypassed by an oil-pressure switch. The switch can run the fuel pump if the relay or it's associated wire harness fails.

This would all be in the GM service manual.

 

[east302]

For future reference, diagram below is for a 1998.

You must be registered for see images attach

You must be registered for see images attach

Sent from my iPhone using Tapatalk

 

[wkobe88822]

great info thanks

 

[joep88cheyenne]

Schurkey, that for the limp home mode. Had a kia that went into limp home but I ran about 1/4 mile and died then had to restart and repeat process. That was no fun. Dealer had to replace comp.

 

[Schurkey]

Schurkey, that for the limp home mode. Had a kia that went into limp home but I ran about 1/4 mile and died then had to restart and repeat process. That was no fun. Dealer had to replace comp.

You could run the gas tank dry on the oil pressure switch with the GM system.

The pump doesn't know the difference between running on the relay, or running on the switch EXCEPT that if the relay or relay harness is damaged, you'd have no two-second prime when the ignition is turned on--so the initial cranking time might be longer. There'd be no fuel pressure until the engine build oil pressure.

After that--no difference.