Another GM Truck Fuel Pump On Its Way Out - I Think

[George7941]

I have been keeping an eye on the fuel pump ever since I bought the truck 15 years ago. Twice a year I scope the current and the latest trace is not encouraging. Fuel pump is original but I only have 218000 kms/135000mi on the truck. Because it is a city driven truck, the hours on the engine are higher than expected from the mileage. The commutator has ten segments and the arrows point to one of the ten humps which is flat, unlike the others.
What would cause the current to flat line like that? A shorted or grounded winding would show high current (large hump) and an open winding would show zero current. Bad brush contact?
I just might replace the pump by lifting the bed rather than wait for it to fail and strand me on the side of the road. RockAuto has a Delphi for $287.60, or a GM Genuine, without the level sensor, for $290.01. I have the 8 ft box and a 133 in WB.

 

[stevejones]

I wouldn't go thru all the hassle of replacing a fuel pump with one that didn't come with a new level sensor - and I've done three of them!

 

[Donald]

Well not sure about your vehicle. I did the fuel pump 2 or 3 times on my 1993 Suburban. The first time when it had not been done in many years the fuel lines snapped and had to replace the entire fuel pump assembly which includes the fuel level sensor. The next time the fuel lines unscrewed OK.

If there are any fuel line connectors under the vehicle start spraying with PB Blaster.

 

[George7941]

I have been spraying Krown religiously at least once a year and I ensure that the top of the fuel tank gets its fair share. I am not expecting rust issues but I know I will get filthy from all the dirt Krown attracts.