Inspecting fuel pump and sock...how to know if they're good?

Bill Cool

Previously 87MustangGT
Founding Member
Nov 18, 1999
1,268
3
39
Seymour, CT
Long story short - once I have a fuel pump out of the tank, how do I know if it's good? If I should replace the sock? If the tank is clean/good?

Extended story - My 87 sat in an outdoor garage for five years. I'd put Stabil in the tank when I put it away, but apparently only had about 6 gallons of gas in there (don't know how I missed that one).

Finally pulled it out of the garage, wouldn't start. Siphoned most of the gas (a nice cloudy yellow), put 4 gal of fresh gas in, new fuel filter, and she eventually started. Would rev to redline while sitting there, but once on the road she wouldn't really go past 2500rpms w/o lots of hesitation/bucking/stuttering.

Get her back to the house, park, and 3 days later she won't start. Go through the crank-no-start checklist, and figure out I have no fuel pressure. Zero at the Schrader valve, tested with three gauges. Fuel does pour out of the valve, but doesn't "shoot" out. 12v at the relay, inertia switch is good and not tripped, and the pump primes with the key.

Today I disconnect the "in" line from the fuel filter, turn the key, and maybe 3 tablespoons (?) of fuel comes out of the line. Again, doesn't really "shoot" out as if under high pressure, more like it kind of "falls" out since the end of the hose is facing down.

I also removed the fuel filter to make sure I'd installed it in the right direction, and poured fuel out of the "in" side. When doing so, the fuel again looked fairly cloudy, and a lot of little black particles came out. Looked almost like soot that had clumped together; each one could fit pretty much inside the loop of the R on your keyboard.

Drop the tank, get the fuel pump out. The sock looks kind of orange, but doesn't appear to be caked. The inside of the tank doesn't appear to be rusty, but I can only see so much. There is some type of sediment in the "tub" of the tank...but I don't know about the rest.

Thoughts on what to do next???
 
If you are taking the time to drop the tank, just replace the pump with a walbro.
155lph at a minimum.
If you aren't going to a supercharger anytime soon, that's good enough.
It will supply over 400rwhp NA.


Change the fuel filter too.
 
A friend gave me a stock pump out of his SN95. Do you think it's useless to replace mine with his?

I wouldn't.
A good pump is only like $75, if you shop well you can find them on ebay for like $55.
Walbro makes the pumps for almost every peformance company that sells them.
With "holley" or "bbk" on the package, you save alot of money.
Peace of Mind with a fuel pump is pretty high on my importance list.
Using a used pump, can still leave you wondering.
 
Fuel Tank

First I would drain everything in the tank out, The sediment in the bottom is what the pump is going to pick up first and pump to the motor, Not the fresh gas that is laying on top.
You can test the pump by hooking it to a 12V supply.(remove the pump from the tank area so that sparking will not cause a fire) The size particles you describe can lock the fuel pump up. I would do this inspection before replacing tank /pump.
 
Tomorrow I'm planning to pour the rest of the gas that's in the tank, out. I'm sure most of the "sediment" that's in there now will come out with the gas, but any thoughts on how can I ensure that everything is out of there, since access/viewing is so limited? I was thinking of shoving a Shop Vac hose in as much as I can, but...
 
just buy a new gas tank, if that car has been sitting for a long time condensation can rust it from the inside out, i had mine rust out at the seam of the tank. there are companies that sell complete kits for new gas tanks for around $200.
 
Got 99.9% of the rest of the gas out, and can't see any more sediment floating around. Also don't see any rust, inasmuch as I can see from the fuel pump and filler tube holes. I'll check again later tonight for rust near the seams, but if there's no surface rust in the "hump" I have to imagine there's none where the gas actually was while stored.