Modern fuel pumps

[jrustles]

I don't have problems with fuel pumps usually. I'm still using an old Denso pump from an '88 MX6 turbo, works great.

I did have a problem with the sock once, though. At less than 1/4 tank, it would suck air during turns or hard maneuvers.

The problem was that the sock which is supposed to lay flat in the "gated reservoir" (which is just a section of gas tank with windage baffles) was not laying flat, and sticking up a little bit. So it was allowing air to be sucked into the pump. Pulled the pump, lay the sock flat, no problem.

But as mentioned, GM fuel level sensors are abyssmal at best. Be sure that you are not in fact running out of gas! We have an 04 Pontiac G6 and the fuel gauge is next to useless. Below 1/4 tank it flails wildly and if you fill it up, it never reads over 3/4. Real POS components there.

 

[supton]

Originally Posted By: The_Eric
^^^^^^^^^^^^^

I do. They offer pumps across multiple applications, with design changes to problematic pumps.


Fair enough, although I'm more concerned with what OEM is using a pump "only" rated for 100k. For a replacement pump I'd be ok with that, as by that point in the vehicle's life I'd be content: but I'm not buying a new car with a fuel pump designed for "only" 100k!

 

[wirelessF]

Is it now fact where import vehicle fuel pumps are way better than domestic vehicles? I had a 91 Sentra where the fuel pump didn't supply enough pressure at 200,000mi. I mis-diagnosed that because the fuel pump was still churning out fuel. My 02 Silverado at 93,000mi just instantly failed luckily leaving enough fuel in the fuel rails to get to the side of the road.

Maybe it has to do with the motor design? Even the motor in the 91 Sentra is beefier than the wimpy motor in GM's "module" fuel pumps.

 

[hattaresguy]

GM's mistake is putting the pump in the tank. They should put it outside next to the filter for easy access.

Having said that your pump is going bad, replace it before it fails. Since you have to drop the tank you really want to do that when its not full!!!!

 

[meep]

I've had 2 pumps fail in my lifetime.

'77 corona (toyota) lost its pump around 90,000. in tank, submerged, probably about a 5-7psi pump.

'84 vanagon, failed around 50,000 IIRC. 50-60psi fuel injection pump, inline on the fuel line. I took it apart (I was probably 14 at the time) and found where the brushes had worn out.

I have wondered about the one in my truck, as it has 120,000 on it. sort of expensive to replace as PM.

 

[Robenstein]

Originally Posted By: hattaresguy
GM's mistake is putting the pump in the tank. They should put it outside next to the filter for easy access.

Having said that your pump is going bad, replace it before it fails. Since you have to drop the tank you really want to do that when its not full!!!!



Then of course removing them can be a pain as the lines often rust. Of course using stainless lines would fix that.

 

[ls1mike]

Originally Posted By: hattaresguy
GM's mistake is putting the pump in the tank. They should put it outside next to the filter for easy access.

Having said that your pump is going bad, replace it before it fails. Since you have to drop the tank you really want to do that when its not full!!!!

What efi car don't have it in the tank? I thought most did.

 

[SteveSRT8]

Originally Posted By: ls1mike
Originally Posted By: hattaresguy
GM's mistake is putting the pump in the tank. They should put it outside next to the filter for easy access.

Having said that your pump is going bad, replace it before it fails. Since you have to drop the tank you really want to do that when its not full!!!!

What efi car don't have it in the tank? I thought most did.


Most do. It's been a trend since returnless systems came out long ago.

And like Supton, I [censored] sure expect mine to last a lot longer than 100k miles! I would think with GM's standard warranty now at 100k miles they are designing them for a long service life.

 

[JetStar]

Most returnless systems still have a return, its just in the tank, with the FPR. The pump works as hard at idle as it does at WOT. Similar to a shunt voltage regulator.
Some MFRs have gone to a variable pump system driven by a PWM driver with pressure feedback via a pressure sensor. Some are a little simpler opting for a two speed set-up. These on demand systems may lead to longer pump life since the pump is not working as hard when it's not needed. Also reduces load on the electrical system, and makes less noise.
When you think about it, these little motors do a lot of work, especially in the constant power systems, 50-65 PSI constantly circulating fuel, its no wonder they are fuel cooled.
Iv'e done my share of GM fuel pumps. One thing that would reduce the pain level would be easier access, like a removeable access hatch. That wouldn't help on pick-up trucks, but it would on Blazers, etc... The newer plastic fuel lines has helped with the rusted fitting issue. Myself and others have experienced short life with cheaper autozone pumps so I avoid those and install OEM pumps bought on-line. If you go to the dealer, they want retail so they can't compete, and in my experience won't price match.
Most of the pumps I have replaced sit in a white plastic cylindrical baffle attached to the bottom of the tank to reduce airiation due to fuel slosh.

 

[hattaresguy]

Originally Posted By: ls1mike
Originally Posted By: hattaresguy
GM's mistake is putting the pump in the tank. They should put it outside next to the filter for easy access.

Having said that your pump is going bad, replace it before it fails. Since you have to drop the tank you really want to do that when its not full!!!!

What efi car don't have it in the tank? I thought most did.


Mercedes don't and most good European cars don't, its up under the frame rail with a filter. Also they have an in tank screen filter which you can access from the bottom to totally drain the tank if you want.

They also use fittings you can get apart, not the clip together nonsense ones that break.

I was surprised when I did the fuel pump on my buddies 2500HD with him how much of a PITA it was, I really don't know why GM chose such a PITA design other than cost. But that's the difference between vehicles that were designed to be serviced and rebuilt in the field, and those that were not.

 

[ls1mike]

That is my point except for the few you mention 99 percent of the EFI cars running around have the pump in the tank. My 02 2500HD at least has an external filter.
I have changed the pump out in bunch of Turbo Dodges, My old Ford Mustang, and a few Fords rangers. All in the tank none of them were fun. When I had my C4 that was an easy pump. It lifted out of the top by removing the filler neck assembly.

When we did my buddies Silverado we pulled the bed it was much easier than dropping the tank.

 

[dailydriver]

Originally Posted By: hattaresguy
GM's mistake is putting the pump in the tank. They should put it outside next to the filter for easy access.


^^^This I can agree with for convenience's sake, but I also can see why they did it for protection's sake (as well as to obtain the CRAZY labor charges at their dealerships for this service {dropping the tank} when out of warranty

).

 

[dailydriver]

Originally Posted By: The_Eric
^^^^^^^^^^^^^

I do. They offer pumps across multiple applications, with design changes to problematic pumps.


Yes, on my LS1 replacement pump they eliminated the external, bottom of module sock strainer, and installed one internally in the module case.
They also reduced the number of internal module support rods because they found that the three rod models were abrading the fuel tube.

They also did motor upgrades, but I do WISH that they had used a geroter type pump motor, like the Walbro.

 

[Shannow]

Did the in tank pump on the Caprice that other day...ran it until the fuel light came on, no spillage and a fairly easy job overall.

 

[hattaresguy]

Originally Posted By: ls1mike
That is my point except for the few you mention 99 percent of the EFI cars running around have the pump in the tank. My 02 2500HD at least has an external filter.
I have changed the pump out in bunch of Turbo Dodges, My old Ford Mustang, and a few Fords rangers. All in the tank none of them were fun. When I had my C4 that was an easy pump. It lifted out of the top by removing the filler neck assembly.

When we did my buddies Silverado we pulled the bed it was much easier than dropping the tank.


We had access to a lift so we dropped his tank and he just replaced it with a custom 45 gallon aluminum one. I couldn't imagine how much of a PITA that job would be without the truck on a lift, or with the tank full! Luckily his started to act up so he had some warning and ran the tank down so we could drop it.

If I had an old truck I'd just cut a hole in the bed, peel it back like a can, change the pump, fold it down and throw the bed liner back in.

 

[ls1mike]

I would LOVE a 45 gallon tank for towing. I have a long bed so I have 34 gallon tank. Was it pricey? The ones I have seen are outrageous!

 

[another Todd]

When I finally change my fuel pump in the silverado I plan on unbolting the bed and lifting it off, or at least moving it back a few feet.

 

[hattaresguy]

Originally Posted By: ls1mike
I would LOVE a 45 gallon tank for towing. I have a long bed so I have 34 gallon tank. Was it pricey? The ones I have seen are outrageous!


He has a short bed so I think his stock tank is a 23? Not sure exactly what he paid, think it was around $900.