Filter sock clogged ?

[Pyrotechnic]

I've been having some fuel pressure trouble lately. I have an 8 PSI Carter pump and a Holley regulator. I could only get about 4 PSI, no matter how the regulator was set so I bypassed it. I still got about the same reading, but with the regulator bypassed, the needle wavered back and fourth regularly, as if their was an inlet restriction on the pump. I had a Fram G3 filter before the pump, which I removed and put in a stainless mesh screen Edelbrock filter I had laying around which is capable of more flow than than the pump is. No change.

The last piece of the puzzle is the in tank filter sock. I've never been into the tank since I've had the truck so it is the last unturned stone. It's also the hardest one to do.

Has anyone ever had one of these filter socks clog up or become restrictive ?

[James McClure]

Pyro, I've seen them plugged but not often. Usually the gas will come out of the pump brown with rust and if you let the sample sit a while and settle out there is water evident. If you don't have either I would look to the rubber lines. The pump pressure going up and down is normal and comes from pump design not a mechanical failure of some kind. vane pumps won't do that, pulse types will. Use clear lines to test. Any bubbles on the suction side? Jim

[Project82]

Pyro , i had the same sort of problem...before i eliminated the problem, my truck would sputter after i took off from a stand still and pegged it to the floor...it would start doing this after it shifted to 2nd...first i thought it was the carb...so me and my dad tore down the carb and cleaned it up and rebuilt it with a walker carb kit...that problem went away for about a day then it slowly started getting worse....so i replaced the fuel pump...did the same as rebuilding the carb...it slowly came back...so i got up under truck and bypassed my tank switching valve since i have duel tanks and its never been replaced...i figured something was getting in the way of the higher fuel pressure my motor needed at a higher throttle...so that helped me out tremendously...but it would still sputter occasionally...after gettin fed up with the problem...i bit the bullet and began dropping the tank...after finding out the tank sending unit is right uder the cab and i couldnt fit my fingers under there with a razor blade to cut the old lines me and my dad had to move the bed back to drop it all the way...btw that was a pain in the a$$...but after i put it all back together it hasn't sputtered or anything since...

Hope this helps...

[staggerd86c-10]

im having the same problem with my truck i just get a hair over 4 psi no matter what pump i put on the truck im almost considering going with an electric pump but i really dont want to where does this problem come from before the valve?

[Project82]

Well if your strainer/sock hasn't ever been replaced on your truck...do that...it will help tremendously...plus if you bypass your tank switching valve unitl you get a new valve it'll run like new...of course that is if you have dual tanks.

PS - I think all this bad gas at the pumps is gettin to our trucks. Which is definitely not helping them get any better.

[Pyrotechnic]

Does anyone know a GM part number for this or where I can buy one ?

I looked on rockauto.com and LMC, and both sell sending units with new socks, but no sock by itself.

[dammitmitchell]

my sock was crimped on, i havent seen a replaceable "sock" on one of these trucks..
but hey you can always tap n dye the end of the tube to make you own sock thingy...
but they dont deteriorate that fast.. especially the new ones
I personally would bite the bullet and replace the assembly while in there. Seeing how it's such a PITA to get to

[Pyrotechnic]

Crimped on.....guess that would explain why you can't just buy the sock.

I have an Edelbrock fuel filter before my pump, and it has a coarse stainless steel mesh element. I doubt the filter sock can filter much finer than it. I'm thinking I might just remove the sock if I see it as a problem when I get into the tank.

Is there a gasket or seal for where the sending unit meets the tank ?

[dammitmitchell]

yes each fuel sending unit has the circle ring that acts as the lock to retain it and below thatis a large rubber o-ring..
when you pull out your sending unit check and wash the ring with some soap n water to make sure all the crap is off op it and clean the surface realllly well.
make sure the ring is not cracked or damaged it could lead to bad issues down the road...
also if u feel confident the fuel filter is enough then just leave the screen off..
good luck

[dammitmitchell]

opps also forgot..
if you have a handy dandy multimeter check the resistance between the + and - it should read no more then 90 ohms and no less then 1...
if you get an OL reading (open line) then your sending unit is bad..
also check the resistor that is on it for a damaged/ rusted spring
check where the little contactor touches the resistor and make sure it's good and not over worn..
and for wear or general weakness and degeneration
if you have never pulled it before there's no telling how long its been and how bad of shape it really is in..
replace it if you deem necessary ...