How do I change fuel pump?

[Spazzalot]

Okay, note to all. Do not ever go to Canadian "only good for tires"
I brought my truck in. It would turn over, no problem there. Everything works, lights etc... But would not fire. Not once. No poof poof miss poof...

It's a 97 GMC Sierra Ext. Cab 4x4. 350 motor.

They went out to truck, it started. Magine that. So they checked a few things and changed the fuel filter, cap and rotor, plugs, and wires.

Thats all fine but hit me for 650 bucks.

I picked up truck...when I started it it revved very high...leveled out normally. I pressed gas and it was like I had put it to the floor. Way too much power for barely touching the gas. I got to the traffic lights half a block away and it died on take off. Nothing. No start at all. Same damn problem they took 650 bucks from me for.

They towed it back to shop. It would not start again. They tested fuel pressure and it has none. So they tell me it's the fuel pump now.

I told them not to touch it. They towed it back to my house. Cuz I didn't feel like putting out another 375 bucks.

Now I am in a pickle. Without equipment...how can I see if it's the pump. They said it's turning but making wierd noises with no pressure.

If it is the pump....how the heck do I change it. I can't find my repair manual anywhere.....gotta do this in morning so any help is appreciated.

Thank you, Lemme know if there is anything I should know.

Spazz.

[Bob B]

A pressure gauge on the fuel rail will tell you. it needs 60 lbs to run.
When you turn on the key, it will cycle for 3-5 seconds then stop unless you start it.
Be sure you replace the filted in case it is plugged. There is also a sock filter on the pump itself to replace when you do the pump. Check the plugs in the harness at and above the pump for burned or corroded contacts.
There is a short wire (I think I remember red) with a plug just under the power brakes that is for testing the pump. You jump 12 volts to it and the pump will run continously. Its just behind the relay box.
To replace the pump, you need to drop the tank. Or as an option lift the bed (8? bolts) My california truck had no rust so the bolts came loose easily. I've done it both ways. My tank was full one time so I lifted the bed. Another time the tank was 1/4 so I dropped the tank. Because this was three pumps in two years, I cut an opening in the bed above the pump while the tank was down. Then I also read that the fuel keeps the pump cool so not to let it go much below 1/4.
I disected the last pump and it looked melted so that may be a good explanation as I had run it low often. I figure now that there is an access hole, It will never fail again. I got a piece of bed from the local pick and pull that is bigger than the opening for a cover.

Bob B

[Spazzalot]

It's a short box. So how heavy is it to lift off the truck?
Are there any wires to be disconnected...
I know to disconnect the filler tube for the tank....
This will be the easiest option.
I have an impact to help

Good idea on lifting the box tho. I wont damage the straps etc this way.

I am going to look for the plug to test the pump.

I was told that it is working but it makes a lot of noise so it's bad. They also said there was no fuel pressure.

Thanks, Spazz

[Bob B]

Originally Posted by Spazzalot

It's a short box. So how heavy is it to lift off the truck?
Are there any wires to be disconnected...
I know to disconnect the filler tube for the tank....
This will be the easiest option.
I have an impact to help

Good idea on lifting the box tho. I wont damage the straps etc this way.

I am going to look for the plug to test the pump.

I was told that it is working but it makes a lot of noise so it's bad. They also said there was no fuel pressure.

Thanks, Spazz

Two of us lifted my shortbed. Three might be a bit better. I used rope to hold it up to the rafters rather than totally remove it. Mine has a fifth wheel hitch and plug and the wiring is straight with no disconnects. So I couldn't lift the rear as far. The lights disconnect ok. There is a ground wire at the rear and also the filler.
One guy on another list said he slid his back 3 feet.

Bob B

[phipps]

Wow, how appropriate that this thread is on the top of the list....my fuel pump went out on my 97 GMC today!!

I'll have to look for the test wire to test mine before we tear it down.

[Spazzalot]

Okay that test wire is easy to find. Look behind the relay box on driver side. It sticks out of the plastic wire loom. About 3 inches long. Red wire. Jump a line from 12 volt to that clip.

I did it worked.

Whoever said changing the pump is easy in nutz.

I now have the tank off. Both the main lines from the sending unit snapped off. The nuts are siezed inside the fittings on the high pressure lines going to front of truck.

Now I gotta buy a sending unit.

Total so far..a lot of money.

If you are gonna change the pump you may as well buy a sending unit too.

[phipps]

You should replace the whole assembly. More often than not replacing just the pump leaves the gas gauge not working. It happened to my brother and the gauge on my truck has never worked so I think the pump was replaced before I bought the truck.

All the replacements I've looked at were the complete assembly.

[Bob B]

[quote=Spazzalot]Okay that test wire is easy to find. Look behind the relay box on driver side. It sticks out of the plastic wire loom. About 3 inches long. Red wire. Jump a line from 12 volt to that clip.

I did it worked.

Whoever said changing the pump is easy in nutz.

I now have the tank off. Both the main lines from the sending unit snapped off. The nuts are siezed inside the fittings on the high pressure lines going to front of truck.

Now I gotta buy a sending unit.

Total so far..a lot of money
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Hi,
I hate to be a know it all, but....
Did you use two wrenches to loosen the fuel lines? I use two wrenches always when there are two fitting nuts. Brakes also. In fact I bought tubing wrenches that wrap around the fittings for better grip and no slipping off.
When I was young I ruined a line by using one wrench. Lesson learned after an experienced mechanic showed me the right way.

Bob B

[HaMSaMMiCH]

amazing, my 97 ex cab short box's fuel pump just ate it as well.... guess its a bad month for gmc fuel pumps..... mine only ran me $160 and i had a shop do it......

[phipps]

Originally Posted by HaMSaMMiCH

amazing, my 97 ex cab short box's fuel pump just ate it as well.... guess its a bad month for gmc fuel pumps..... mine only ran me $160 and i had a shop do it......

Did they change the whole module or just the pump itself? Around here the module alone was at least $250 no matter where you got it. I ended up paying a little more and getting it from Napa rather than AutoZone.

[HaMSaMMiCH]

they replaced the pump, strainer, filter, and the small rubber line on the sending unit.

my k1500 is a rebuild with a swap though so they had to drop the tank a coupple times before we got the right pump in... mechanics were nice and straight forward, didnt charge by the hour either, $90 for labor $70 something for parts.

brought the truck back to them this morning to get my rear end seals done, pinion seal, axle seals, and rear seal all for $93 and change

[HaMSaMMiCH]

amazingly, one of the coustomers at my girlfriend's, dad's bar who owns a white 97 chevy k1500 z 71(mine is a black 97 gmc z71 with a chevy front end) had his fuel pump go out yesterday night while he was leaving the bar.

i saw he was having problems, and i walked over to the truck and didnt hear the fuel pump turning. i told him what happened to my truck and we had a good laugh about it

[Bob B]

All these pumps going out reminds me of another list I'm on.
Old British Land Rovers 4WD.
They usually get a name from the owner for one reason or another. Like a member of the family.
One lister calls his Nigel. He posted about a particularly rare failure then within a few days several others had the same problem. Now when this happens on the list, it is called Nigel's disease.
Bob B

[mikemac98sierra]

I have a 98 Sierra with a 4.3L and my fuel pump quit on me a couple of days ago also. I am pricing new pumps and a new one is going to run me around $600, and that is the fuel pump and sending unit because they are apparently one unit. My fuel gague started acting funny a couple of months ago and i let it go which i am glad i did because the part to fix it on the pump was 170, and you cant buy just a fuel pump where i am at, you also get the gague part, that is the only good news that i have gotton out of this whole mess.

[Bob B]

Originally Posted by mikemac98sierra

I have a 98 Sierra with a 4.3L and my fuel pump quit on me a couple of days ago also. I am pricing new pumps and a new one is going to run me around $600, and that is the fuel pump and sending unit because they are apparently one unit. My fuel gague started acting funny a couple of months ago and i let it go which i am glad i did because the part to fix it on the pump was 170, and you cant buy just a fuel pump where i am at, you also get the gague part, that is the only good news that i have gotton out of this whole mess.

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yup!,
On my 97 K1500 pickup,the fuel pump is available separately. Ebay has them for $45.00 plus $5 shipping. That's Delco too.
Starting with a friends 97 1500 Tahoe, and newer, only the whole thing is available. They call it a module. cost around $250.00 to $350 around here probably also on ebay lookat: for $140.00 plus shipping. http://cgi.ebay.com/ebaymotors/NEW-A...P-97-00-CHEVY-
GMC-TRUCKS-MU146_W0QQcmdZViewItemQQcategoryZ33555QQitemZ80424 9860
3QQrdZ1QQsspagenameZWDVW
Bob B