Re: Fuel pump whine?

This has just been my experience with GM's of the past couple of decades, mainly in GMC's, Chevy's and Cadillacs, but they have all had fuel pump whine from the day one.

Never had a fuel pump problem though... my 2000 Tahoe LT 4x4 has 50,000 miles on it and it whines like it did the day I bought it.. no problems...

Is that what that is? My '03 'Burb has had a whistle from day 1 that I haven't been able to place in order to show it to the dealer.

-Stan

Good tip about the fuel filter. I'll give that a try. If it still whines, maybe I'll just watch it for awhile.

HMc

One tip that might help (if the pump's on the way out) is to keep at least a half tank or more of fuel....it helps to keep the pump cool...

Jeremy

I had a OEM replacement put in my 92 S10. It whines quite loudly. I asked themechanice about it and he said it is fine.

I had a 200x Chevy van pull up beside me one day and I could hear his with my windows up.

Lannie

I've got a '99 K2500 that has the same type of whine. I bought the truck used, and the fuel pump died about 2 months later. I recently had more problems with fuel delivery, and ended up having to change the fuel tank. Seems that if your EVAP canister is bad or flaky, it will pull enough vacuum on the fuel tank to collapse it. My fuel tank was scrunched in about 3 inches deep along the inner edge, and about 2 - 3 inches along the bottom edge. Couldn't tell by looking at it because of the plastic outer liner over the tank. This also caused my gas gauge to read incorrectly, since the bottom of the tank was scrunched up, it made the fuel level sender arm go to the top of the tank and show about 3/4 full when she was full. It also seemed to cause an intermittent 'vapor lock' type of problem.

Ed

RE/

My '98 made a loud sound from the day it was new to when I had a premptive replacement done at 100k a few weeks ago. Now it's silent. Dunno whether to worry or not -)

Wouldn't call the original noise exactly a "whine" - more like a loud buzzing muffled by fluid....but I used to wonder what it was until somebody pointed out the obvious.

----------------------- PeteCresswell

So your vapor lock type of problem is gone now? I have a 95 blazer that has a vapor lock type of problem on hot, humid days. I've been using SeaFoam and praying for temps below 90.

Art

Seems to be for now, I am still slowly trying to troubleshoot the EVAP system. But until I am finished, I make sure that the filler cap isn't on very tight. We've also had a week of "cool" weather, so I am not 100% certain it won't happen again.

For what it's worth, I used to work for a company that made the plastic fuel tanks for most large Chevy trucks (GMT800) as well as the Dodge Ram trucks, among others. In quality testing of the tanks before shipping, all the GM specified pumps seemed to be quite a bit louder than the ones that Dodge specified. I think it was Denso that made the GM pumps? I hate to say it's "normal" for them to sound loud, but I think that is/was the case.

Now on the 99 Dodge Ram that I owned, the pump was quiet, until about 24K miles, when it got really loud, and about a week later failed. When replaced, it was quiet as could be, and has been ever since, 112K miles later. Go figure.

And to the comments about the EVAP system collapsing a fuel tank, I highly doubt this is possible. The vacuum pressure required to do this isn't reached in an EVAP system. We used to use scrap tanks as step stools. They do not deform with #200 pounds of weight standing on them, so I'm sure a vapor return line won't do much either. 26 gallons of gas weighs about 208# and the tanks don't deform under that load. Part of the tank testing is to freeze them when filled with water, and then drop the tank and ice inside from 2 stories up. The tanks must not deform, burst, or leak after that test to be considered good. Sounds like someone drove over something and crushed the tank. Just a thought.

Unless the tank is metal with a plastic shield under it like in my 94 Jimmy.

Yes, there is enouch vacuum to collapse a steel fuel tank, especially on a long trip starting with a full tank, AND if you have a faulty fuel tank pressure sensor that reports overpressure in the tank. The valve will stay open and the intake manifold will suck as much gasoline fumes as possible. That along with the fuel pump removing the liquid from the tank and a tight gas cap will easily do the trick.

When looking through the junkyards for a replacement tank, ALL of them I found from 98 and 99 models were collapsed in to some degree or another, all on the inside seam and some on the bottom too. Mine was the worst, about

One guy I talked to said he used to be a GM service tech and since the new emissions laws and design changes in 96, he saw several collapsed fuel tanks that he believed was due to the EVAP system.