03 Sierra 5.3 died. Can't hear the fuel pump

[absinthminded]

Yesterday my truck died while exiting the highway. I tried the key a few times and I could not hear the pump prime. After a tow truck ride home, I pulled the bed. I wanted to do this for a while now. It sucked! 14yr old truck that has lived through Michigan winters its whole life. I only had to cut out one bolt. The other 7 took everything I had to remove them. I got the new pump (Delco from napa). The fuses and relay seem fine. I'm waiting on a buddy to check the fuel pressure and hopefully he can test voltage at the harness just to be sure the pump is bad before I have to wire in the new one.

Is there anything else I'm missing that I should check? Truck has 225k on the clock now and the pump is original. Thanks

[Jsdirt]

It was the fuel pump. My buddy came over and checked voltage at the pigtail well i cranked the engine over. it had plenty of power. The fuel pump ring was rusted the hell and I beat on it with a chisel and hammer And soaked it down with WD-40 and left it overnight. The next day I got it to come off with the punch and a hammer.I went and bought a new ring in the new filler neck because mine was rusty and broken. I went to Napa and got a Delco fuel pump and sending unit I hope it lasts. I wire wheel all the bolts that held the bed down game a good coding of copper antiseaze before I ran them back in. Pulling the bed sucked. 4 wratchet straps and a cherry picker made it possible by myself.

 

Glad you got her figured out and fixed!

 

Yeah, gotta love rust. Everything I touch is exactly like that. Torches and hammers are common "hand tools" in the Northeast here.

[mjoekingz28]

At that mileage, I'm gonna say you're on the right track.

 

You're lucky you got a Wednesday pump. Mine is starting get loud with just 90k on the clock. I got the Friday-night-before-New-Years TRUCK ....

 

So the UAW got a head start on the holiday?

[Jsdirt]

Apparently. Everyone must've been drunk on ball joint, strut, brake, and interior day.

[Hoginedgewood]

my last fuel pump went bad at the output, the metal pipe that is part of the pump exiting the tank. it rusted out. ten Cincinnati winters. I'd concider undercoating the top after its all together. and put some silicone grease in the connectors to keep out moisture.Not caulk.

[Jsdirt]

At that mileage, I'm gonna say you're on the right track.

 

You're lucky you got a Wednesday pump. Mine is starting get loud with just 90k on the clock. I got the Friday-night-before-New-Years TRUCK ...

 

Don't forget, a couple wires are going to be for the fuel gauge. Same wire that supplies voltage during prime is going to be supplying voltage when the engine is running.

[barry G]

I would wager wires are good.

 

get a whole assembly, it has fresh lid, o-ring gasket.. pump and newer style screen, fuel level sender all at once.

 

about a hundred bucks if you look around.

 

I learned 96-98 had a dramatic update. Avoid "new old stock"

not sure on your 03.

2008 was last worldly update on the pumps (millions of vehicles).

 

my 96 became very powerful. It was comical.

Never been there its whole life...just the new pump.

[Jsdirt]

Gotta check 'em anyway. Foolish to install a pump before verifying voltage AND ground at the pump. At this mileage it's a moot point, but you're in there - might as well check.

 

Many a mechanic has been slid by calling a fuel pump, when all it needed was wiring or connector repair.

[absinthminded]

I got a purple, a gray, and 2 black wires at the pump connector. I'm guessing I should see at least 12v at the gray wire? It's powered when primed but is it powered when the key is at aux or just cranking?

[absinthminded]

It was the fuel pump. My buddy came over and checked voltage at the pigtail well i cranked the engine over. it had plenty of power. The fuel pump ring was rusted the hell and I beat on it with a chisel and hammer And soaked it down with WD-40 and left it overnight. The next day I got it to come off with the punch and a hammer.I went and bought a new ring in the new filler neck because mine was rusty and broken. I went to Napa and got a Delco fuel pump and sending unit I hope it lasts. I wire wheel all the bolts that held the bed down game a good coding of copper antiseaze before I ran them back in. Pulling the bed sucked. 4 wratchet straps and a cherry picker made it possible by myself.

[Colossus]

How long have you had that truck? I had a 05 like that for about half a year. (minus those rims) I liked the two tone and it served me well while I had it.

[50blues]

Don't forget the fuel filter.