Suburban mafia fuel pump question

[mchambers]

2001 suburban 1500 with 150,000 on the clock. I drove back from Asheville on Wednesday, probably 3 to 3.5 hours of highway speeds time. When I stopped to drop off a passenger I heard a very loud humming buzzing sound coming from the rear of the vehicle. I didn't notice any performance or hesitation issues. I drove another 5 and it was still there. I have always maintained a quarter tank minimum and it has rarely ever dropped below that since I have owned it in the last 2.5 years but can't speak for the previous owners. For the two days since then doing short trips of 10 miles or less I haven't heard it again. I suspect an impending fuel pump failure. Just want confirmation of what I suspect. So what do you think?
I have already priced out a replacement Delphi unit at my local NAPA store for $269.

Any tips for changing out the pump in my garage without a lift?

 

[rayra]

It's basically right under the second row driver's side seat. The only things further back that should or could be making noise further to the rear are the subwoofer and rear speakers, and the rear AC cage fan. Your noise could very well be your pump. Sure it wasn't a vibrating license plate frame?
Typically - besides an outright failure symptom while driving, you'll get a period of very loud operation before it fails. And you should be able to hear it plainly when you just turn your key to ON. You should hear it priming / pressurizing the fuel system. You can hear it normally if you really listen for it, so don't be misled by a very faint noise. It should be quite a bit louder / obvious.


As for taking it out, I've seen a bunch of anecdotes online and some videos, sure seems like a struggle to get it done in a driveway / sans lift. IF you have proper heavy duty jackstands I'd suggest getting it as high in the air as you can so you have room to work. You've got to free the tank and shift it fore and aft to drop the rear end and lower the front enough to disconnect everything from the pump / top of the tank to get it all free and out in the open where you can properly swap it out.

Me, when the time comes, I'm cutting a hole in my floor. There's a guy on youtube that shows a very simple method to locate your cutting location and viola, there it is sitting right there, easy to get to and service. I have a 14yr old Used vehicle so I can freely modify it however I wish. I have zero qualms about cutting a hole in the floor to change the fuel pump. And putting it back together in a water-sealed fashion.


Here's the video I was talking about. https://www.youtube.com/watch?v=Ho2pk8okztE

There are several others showing reasonable procedures for doing it in the driveway.
https://www.youtube.com/watch?v=g-JnQzQ81kc
https://www.youtube.com/watch?v=hyegeWo1VbM
https://www.youtube.com/watch?v=3mjaQv-VcZU


and yours doesn't sound like a bad price, but I suggest checking rockauto.com too. The savings there over a local chain can be enormous sometimes.

 

[mchambers]

I saw that video about cutting a hole in the floor but that is above my pay grade at this time. It was definitely an electrical or possibly a rotational sound. I wonder if it just got hot pumping fuel for 3.5 hours or so. I do have heavy jack stands and have watched videos of how to change it out. The biggest thing I have is a guy who is half my age and has done it before! LOL Definitely doesn't look like a single person job. I looked a rock auto and my price is about the same as the highest quality pump Rockauto.com has maybe $20 more but I don't have to wait for it to get here either. My tank is as close to empty as I can get it. I have never seen my low fuel light come on before today! Needle is pointing a little below E and have been riding around with a gas can strapped to the back just in case. I do a decent amount of highway travel and would hate to break down and have to pay a tow bill and a high fee to change it out wherever I am when it fails.
Thanks Rayra! Have a great weekend.

 

[02TahoeMD]

Hi Rayra - the fuel pump job can be done in a driveway. I did the one for my Tahoe a few years back, alone. I think if I would have had an extra pair of hands it would have made it easier since the tank was not completely empty. I did jack up the driver's side of the truck and prop it up with jack stands. I then used the jack to support the middle of the tank along with a piece of plywood to spread out the load as I undid the straps. Again....an extra pair of hands would have been quite valuable.

I would highly recommend getting the correct disconnect tools for the gas lines as it will help make getting the tank out easier. Also, clean the upper surfaces of the tank once it is down and keep a shop vac handy so no debris falls in the tank. If you havent already, also get the set ring that locks the pump to the tank. Mine was pretty corroded, I painted it but in hindsight wished I had gotten a new one since the process was such a pain in the butt.

If the fuel pump is not the issue that is causing the noise, at least you will have tackled the part replacement before it cost you a ride on a tow truck.

 

[Mud Dawg]

I did the "cut the hole in the floor" method. Just followed the YouTube vid. It was so easy it was almost criminal. I don't know for sure, but I can't see how dropping the tank would ever be as easy.

My symptom: truck would have to be "turned over" 3 or 4 times before it would start.

 

[NMC_EXP]

Me, when the time comes, I'm cutting a hole in my floor.

I had a 1962 Dodge M37B1 3/4 ton truck (military version of the Powerwagon). It came factory equipped with a fuel tank access plate in the bed.

My how we have progressed since then.

 

[Mud Dawg]

I had a 1962 Dodge M37B1 3/4 ton truck (military version of the Powerwagon). It came factory equipped with a fuel tank access plate in the bed.

My how we have progressed since then.

Ain't it the truth!

 

[NatersXJ6]

CUT THE FLOOR!

Disturbing the hoses on the filler neck leads to all sorts of leak issues, potential vent failures (tank won't fill properly with a twisted, broken, or blocked vent line) and general unhappiness.

cutting the floor is quick and easy and using silicone or Right Stuff gasket maker will re-seal the floor forever.

Just be careful of the sharp edges when reaching through your newly cut hole to change the pump.

 

[Martinjmpr]

So when you cut the hole in your floor, do you bolt a door into there or something?

 

[Mud Dawg]

You just put the panel back. One side rests on factory rib and you have to add a cross piece on the other side to screw it to. It sounds complicated, but it's not. The vid explains. I sealed the cut with one run of HVAC tape and some gorilla tape on top of that.

 

[Stryder106]

Dangit!!! reading this thread cursed me. I had a new fuel pump put in my Avalanche 3 years ago and it cost quite a bit of money to have the shop do it - as it had gone out on the road and I had to have it towed there. So, reading this thread and checking out the video of how to cut an access door in the floor, I thought to myself - that's an awesome idea, I'll do that as soon as I get back from my Mojave Road trip on Thanksgiving. And wouldn't you know it, I go out to go somewhere in my Av and low and behold - what do I hear? The loud fuel pump is about to die sound form the last time. I have absolutely no time right now to undertake that mod given other stuff I'm doing, so it's at the shop, again; getting a new fuel pump, again; and going to cost me a lot of money, again. Oh, BTW - plan on changing your evap canister as well, mine just crumbled. First thing I am doing when I get back from TMR is cutting that access panel and picking up a spare pump motor to carry in my rig.

 

[Martinjmpr]

I really like this idea. Not only is it easier/cheaper than dropping the tank, but I would have nightmares about something getting damaged or not put back together right when removing or reinstalling the tank. Having the hole in the floor removes those issues, no need to disconnect fuel lines, vent hoses or anything like that.

What do they use to actually cut the panel out? A cut off wheel or grinder or something? I can see how it would be tricky - you can't cut too deep or you'll hit the tank!

 

[Mud Dawg]

I used a Dremel tool with reinforced cut-off wheel. Kind of tedious, but not too bad. The metal isn't as thick as you might think....

 

[Jelorian]

You just put the panel back. One side rests on factory rib and you have to add a cross piece on the other side to screw it to. It sounds complicated, but it's not. The vid explains. I sealed the cut with one run of HVAC tape and some gorilla tape on top of that.

What did you use to cut out the hole and did you do anything to prevent sparks? I've heard of guys spraying water underneath if using a cutoff wheel. Definitely something I want to do in the near future.

 

[rayra]

Primary trick with the cutting wheel is deciding which way you want the sparks to throw and controlling the tool in the manner to achieve that. Moving the cuttign disc (any type / size) so the disc cuts into the direction of travel of the whole tool will throw sparks up and out of the cut, instead of casting them down on the tank / undercarriage. Use a tarp and damp towels to control things inside the vehicle.

The other is use a powered saw instead and control your depth of cut. No / few sparks.

Another is use something like an air-powered nibbler. No sparks at all for most of the cut.

I'm going to use an air powered handheld saber saw, has a short stroke and it has a wire standoff guide to further limit the depth of cut. I should be able to readily cut out the opening. I might do it sooner rather than later, as I'll soon have most of the rear apart doing several other project portions all at once, while I finish the cabling for my rear power mods, run the wires for my rear camera, run some leads for rooftop solar connections and modify both cargo side panels (driver side for a big power plug, pass side to elongate the rear AC intake vent slots) AND install some eyebolts for a rear cargo net / barrier behind the 2nd row. I'll have the second row seats out and carpet up anyway. And when I previously heavily sound insulated the floor I left that fuel pump area uncovered on purpose for cutting the hatch.

I'm also likely to scrounge up a metal hatch to retrofit into the opening, or turn the cut piece into a hinged hatch. I can add flanges and gasket material to the floor opening edges and use sheet metal screws to seal it shut, then cover it over with butyl tape or metal ductwork tape to seal it up completely. Then when I get around to doing the pump itself it will be a simple chore.