Is it my fuel pump or my imagination?

[Searay45db]

So here is the $64k question, as I get ready to go of with a bunch of Boy Scouts and a big trailer this weekend. In my regular 5.3 Yuki, when you go to the on position, you can hear the fuel pump. On this one, I cannot. Since you guy's have the 6.0, and there seems to be more insulation, is that something you do hear or don't? Thanks!

 

[Searay45db]

See the image of the fuel pump door inside the cab

View attachment 182923

When you turn the key on, can you hear the fuel pump? I cannot on mine but it seems to be running fine again...

 

[Searay45db]

My 04 Denali had similar symptoms. Guage would read 55 with key on and start right up. Shut it off and pressure would slowly slowly drop to around 35-40 after an hour or two. Kept an eye on it for a week and soon it wouldn't start on first crank anymore. Always would the second time. Replaced with a Delphi and it starts right up everytime now. Tank wasn't very hard at all to drop. Some fuel line disconnects and a 15mm socket and you should have it down in about an hour and half at most. Be sure to order new straps and hardware because they are almost guaranteed to strip and spin on ya resulting in cutting straps

When you turn your ignition on, can you hear your fuel pump? I cannot hear mine, yet its running fine...for now...

 

[DenaliJJ]

When you turn your ignition on, can you hear your fuel pump? I cannot hear mine, yet its running fine...for now...

Yes you should be able to hear it prime.

 

[ivin74]

Great pics. What did you cut the floor with? How did you seal it back up?

I used a grinder with a cut off wheel (Harbor Freight has all you need for under $25 bucks), I'm glad I did that mod because I have not had much luck with fuel pumps.

In the next couple of weeks I'm going to replace the carpet and when I do I will take some measurements for people to know where to cut it.



https://www.harborfreight.com/4-12-in-43-amp-angle-grinder-69645.html

https://www.harborfreight.com/4-12-in-40-grit-metal-cut-off-wheel-10-pc-61195.html

 

[ScottyBoy]

I had somewhat similar symptoms to you when my fuel pump went out. Every so often my fuel gauge would randomly drop all the way to empty and my low fuel warning light and chime would come on. But usually when that happened, I would shut off the engine and then it would be fine when I started it back up. It did that off and on for a few months. Then every once it a blue moon the engine would sputter like it was about to die. I gave it more gas pedal and then it started running fine again. Weird... But I never did think it was fuel pump related. Then one day my wife takes off in my truck, and when she stopped at the stop sign at the end of our block, the engine died and would not start back up. Normally she would have been driving her own car, but it was in the shop and she had a Nissan Sentra as a rental which she absolutely HATED, so she basically took control of my Burban. To make a long story less long, I ended up towing a big ass Suburban with a 2017 Nissan Sentra. It was only one block, and I kept it under 10mph the whole time, but it was still funny as hell. Got the Burban in the driveway and spent the rest of the day diagnosing it, and I confirmed 100% that the pump was bad. I ordered a new AC Delco pump from Rockauto, so $150 and 3 days later I had the pump.
I installed it myself in my driveway in two days. You need to get it jacked as HIGH as you possibly can. I had the two front tires on ramps and the rear was up as high as possible on 12ton jack stands. You need it as high as possible so that you have enough room to drop the tank, and then slide it out. My 17yr old son helped me with part of it. Disconnecting all the emissions lines and fuel lines was hands down the most difficult part. That's difficult because you have to drop the tank a little, then disconnect the lines, then you can drop the tank the rest of the way. I have a bad back, so it did take me two days, mostly because I had to stop after I got the tank completely removed because I was in so much pain. But most people should be able to get it out, swap the pump, and then get the tank back in all in a single day. Now here's all the tips I can give you from my experience tackling this job.
Just try to remove as much fuel as possible from the tank. I disconnected the fuel fill hose and leaned the tank down and a few more gallons poured out into a bucket.
Cover all openings with tape or aluminum foil or something after you disconnect the lines. The less dirt and debris that gets into the tank, the better. And if you can take a few minutes to prevent more dirt from getting in, then DO IT! Keep PLENTY of towels or rags nearby to quickly wipe up any fuel spills. Cardboard and oil-dry will help with this as well.
Be sure that you have a set of quick connect release tools in order to get the fuel lines disconnected. I have a set from Harbor Freight and they work "ok". I'm sure there is a better set of them out there, but I don't have any experience with anything other than this set.
And my biggest tip of all is to DEFINITELY get a genuine AC Delco fuel pump!!! I have seen lots of people use other brands and they ended up having to replace it again within a year or so. I do NOT recommend getting an AutoZone fuel pump (regardless of the lifetime warranty) unless you plan on getting rid of your truck within the next year. If you are keeping your truck, get the Delco pump. The Delco pump also comes with a new wiring harness pigtail. This is a very common failure point in these trucks. This is something that you should focus on before you replace the pump. A bad pigtail can cause all the same symptoms as a failed fuel pump. So when you are diagnosing your truck, pull the pump pigtail down and test it and inspect it for any signs of corrosion, damage, or melting.

 

[JonnyTahoe]

My fuel pump went out at 130k and I used the autozone brand and went to shit in 12k miles, had to place it again but the 2nd time I used the oem pump no issues since. I did not drop the tank at all, remove the drivers rear bucket seat cut a hole on the floor board and pump was out in no time. Best mod ever, I cant believe GM did not install an access door for the pump.

GM is not thinking of you replacing fuel pumps when designing truck floors. Do you really think GM wants you working on your trucks fuel tank.

 

[JonnyTahoe]

I had somewhat similar symptoms to you when my fuel pump went out. Every so often my fuel gauge would randomly drop all the way to empty and my low fuel warning light and chime would come on. But usually when that happened, I would shut off the engine and then it would be fine when I started it back up. It did that off and on for a few months. Then every once it a blue moon the engine would sputter like it was about to die. I gave it more gas pedal and then it started running fine again. Weird... But I never did think it was fuel pump related. Then one day my wife takes off in my truck, and when she stopped at the stop sign at the end of our block, the engine died and would not start back up. Normally she would have been driving her own car, but it was in the shop and she had a Nissan Sentra as a rental which she absolutely HATED, so she basically took control of my Burban. To make a long story less long, I ended up towing a big ass Suburban with a 2017 Nissan Sentra. It was only one block, and I kept it under 10mph the whole time, but it was still funny as hell. Got the Burban in the driveway and spent the rest of the day diagnosing it, and I confirmed 100% that the pump was bad. I ordered a new AC Delco pump from Rockauto, so $150 and 3 days later I had the pump.
I installed it myself in my driveway in two days. You need to get it jacked as HIGH as you possibly can. I had the two front tires on ramps and the rear was up as high as possible on 12ton jack stands. You need it as high as possible so that you have enough room to drop the tank, and then slide it out. My 17yr old son helped me with part of it. Disconnecting all the emissions lines and fuel lines was hands down the most difficult part. That's difficult because you have to drop the tank a little, then disconnect the lines, then you can drop the tank the rest of the way. I have a bad back, so it did take me two days, mostly because I had to stop after I got the tank completely removed because I was in so much pain. But most people should be able to get it out, swap the pump, and then get the tank back in all in a single day. Now here's all the tips I can give you from my experience tackling this job.
Just try to remove as much fuel as possible from the tank. I disconnected the fuel fill hose and leaned the tank down and a few more gallons poured out into a bucket.
Cover all openings with tape or aluminum foil or something after you disconnect the lines. The less dirt and debris that gets into the tank, the better. And if you can take a few minutes to prevent more dirt from getting in, then DO IT! Keep PLENTY of towels or rags nearby to quickly wipe up any fuel spills. Cardboard and oil-dry will help with this as well.
Be sure that you have a set of quick connect release tools in order to get the fuel lines disconnected. I have a set from Harbor Freight and they work "ok". I'm sure there is a better set of them out there, but I don't have any experience with anything other than this set.
And my biggest tip of all is to DEFINITELY get a genuine AC Delco fuel pump!!! I have seen lots of people use other brands and they ended up having to replace it again within a year or so. I do NOT recommend getting an AutoZone fuel pump (regardless of the lifetime warranty) unless you plan on getting rid of your truck within the next year. If you are keeping your truck, get the Delco pump. The Delco pump also comes with a new wiring harness pigtail. This is a very common failure point in these trucks. This is something that you should focus on before you replace the pump. A bad pigtail can cause all the same symptoms as a failed fuel pump. So when you are diagnosing your truck, pull the pump pigtail down and test it and inspect it for any signs of corrosion, damage, or melting.

GREAT WRITE-UP SCOTT. I give you credit for doing this nightmare job yourself. You made a great recommendation to go with the OEM Delco pump you Definitely only want to do this job once. I would think a ''Auto Store'' pump would and should go more than 12k miles and even with a warranty you still have to replace it again. I'm thinking of the day when I may have to do this job as my '00 has 280k miles on it and it will likely be this January when its -20 below zero outside.

 

[ScottyBoy]

Also, for those who mentioned cutting an access hatch under the rear seat. A lot of foreign cars actually have fuel pump access doors under the rear seat. I changed a fuel pump in a Honda Civic like that. But the main drawback is that the interior of the car WREAKED of gasoline for weeks, probably over a month. Nothing got rid of the smell except giving it time to dissipate on it's own. Yes, it makes the job a bit easier, but if you use a genuine AC Delco pump, then you should only have to replace it about every 10-15 years or so. My original fuel pump lasted 16 years! So of course that's exactly what I wanted to replace it with, not some cheap made it China crap that will save me about $30 but I will end up having to change it every year or so.

 

[ScottyBoy]

GREAT INFO Scott !!

Like I said, check that pigtail first. If the pigtail us damaged in any way, that may be your only problem. So definitely be sure to inspect and test that first. And if you end up needing just a pigtail, shoot me a private message because I did save the new one that came with my new fuel pump and you are welcome to have it. It's just collecting dust in one of my tool boxes.
You can probably also call your local Chevy dealer and give them your VIN to see what all warranty/recall work was done on your truck. If that pigtail was replaced under the recall, then you should have a newer style (and heavier duty than the original) pigtail already soldered on to your fuel pump harness. It's definitely worth checking into.