Fuel Pump going bad?

[Sierra89]

Hi all,

I just picked up a 2005 Suburban Z71. It's in great shape overall, but of course has a few items that need attention. I have noticed that the fuel pump is humming loudly, louder than any of my other trucks. Is this a sign that it's beginning to fail? If so I'll prioritize it's replacement. The Burb is closing in on 20 years old so I wouldn't be surprised.

Thanks.

 

 

[richard wysong]

my pump would hum loudly with 1/4 tank of gas or less, did that for many years then failed with no warning with a full tank a couple months ago. $160 for the tow and $150 for the fuel pump module at Advance ap. probably not a bad idea to change it if just for the peace of mind

[redvett]

How many miles? GM started to use a returnless fuel system and thay have been known to last 180000 to 300000 miles, they are very robust systems.

[dna9656]

I suppose the "no return" fuel system was easier on the pump? For years and years we had low pressure pumps up under the hood; and I know it's easier to "push a fluid that to draw a fluid, so ok, build a better pump and draw the gas, that way changing the pump and\or filter would be a WHOLE LOT less complicated....

I bought a 06 avalanche Z71 with 80 k on the clock. It had issues.

The oil pressure sending unit was original, it had the screen in it.

I tried overhauling the instrument module without any luck (change the gasge motors and replace burned out LEDs. How is it home lighting LEDs last thousands of hours but the ones in cars just a few years? I think GM got pretty cheap there in the early 2000s.

Replaced the rear axle tube seals, changed the lube in the rear axle to synthetic. Replaced the rotors and brake pads all the way around. both axle hubs up front. Complete replacement of all steering components except the pitman arm and center link. Driver's side valve cover, all the rockers, oil pump, the infamous O ring on the oil pick up tube, the oil pickup tube, timing chain and gears, and the T-chain cover, oil pan gasket duh, 2 ignition coils, all the plug wires and plugs, universal joints.

I replaced the driver's seat foam and cover, radio, it had an after market radio in it, I think the used car dealer I bought it from swapped it out for his own car. The truck had a THUMP THUMP stereo in it; I'm too old for that kind of stuff.

There was a speaker baffle in place of the mid gate, it held 2 giant speakers and the amp. Sold that stuff and bought a junk yard mid gate.

At one time the truck had those lights installed, you know the ones that blind anyone that's in front of them? The wiring was left but the lights were gone, there were 2 little boxes that went with those lights, they were left installed. The 4 X 4 Z71 had 22" X really wide tires on it, when going down the freeway the truck would get into the rut(s) and the car would follow the ruts, it was like one side of the truck was in a rut and the truck would follow that rut. I sold that stuff and got some stock sized Chevy aluminum wheels and new tires.

I got the truck aligned when I rebuild the front end, another "duh". I replaced the fuel pump because it was shaky, and (in front of the intake) AIR sensor. I had the usual 4L60 transmission issues, thunking and what not so I asked around for the best tranny shop in the county and took it there. I had the shop upgrade the tranny to the Escalade/SS spec. tranny (4L 70). This adds more steels and clutches and other components, it was a $500 upgrade. While there I scrounged some minor parts and hardware from the shop's junk pile. I noticed a LOT of old transfer cases piled around; I asked why and was told the pump in the transfer case wears a hole in the back of the case and the tranny fluid leaks (gets pumped) out thus the innards burn up due to a lack of lubrication. I had never been in a transfer case before. So far as I knew it was like a Swiss watch inside full of tiny parts and such. Well it isn't. The tranny shop uses a thin steel (sheet metal) shield between the pump and the case, I went better and bought a Merchant Automotive cast aluminum part, they warranty for life that it's do it's job so I went with that. It was pretty easy to install actually, so I would recommend anybody with that transfer case do that.

I installed a water pump, power steering pump, A/C belt tensioner, the alternator, all hoses, a battery, the current sensor that's on the negative battery cable. There was a blue aluminum spacer between the AIR sensor and the intake; it was one of those "increase your horsepower and get super gas mileage with this super-duper thing. It being there made installing the water pump a real pain. AC Delco lists 2 water pumps for the '06 5.3; one fit a hair better and the other because the upper outlet was clocked slightly differently but the real problem was the AIR spacer.

I didn't all this in one month, I got the truck in September of '16.

Ah; the adventures of buying a used truck. Had I known more about this particular truck and the shyster I bought it from I would have bought elsewhere he also promised me more conventionally sized wheels and tires; he dragged his feet about  the promise until I got sick of it all, part of his business model I'm sure. So, note to self: get all promises in the contract and get them fulfilled before cash exchanges hands.

[Sierra89]

Thanks for the replies guys. The 'Bourbon' has 140,000 miles on it. The only reason I even thought about it being an issue is because my Sierra is up around 200,000 and I have not noticed the humming. When did GM start using the returnless fuel system? is it on all truck models from then on?

Thanks again,I have no problem swapping in a new pump on an almost 20 year old vehicle, good peace of mind.

Cheers.

[redvett]

GM started the returnless fuel system on pickups in 2004 on V8's and Tahoe & Suburban 2003 and continue up until current production, the returnless system was dictated by the Fed's vapor emission requirement.

[Supreme Pizza]

I personally would not change a fuel pump based on its noise level unless it was REALLY loud or making very abnormal noises. But that's just me.

[richard wysong]

I agree, theres lots of reasons they may be noisy. I got around 70k miles out of a pump that was noisy with 1/4 tank or less which came in handy cuz the gauge didnt work under 1/2 a tank, that was a Delco pump from the dealer that I got after the Napa 1 I installed was really loud, I had to change it a couple months ago after it failed with a full tank. new 1 nice and quiet and the gauge works.