Bone Dry Fuel Tank

[Wheeler88]

The truck in my signature has been sitting/parked for the last 5 months with a just about empty gas tank. I changed the oil today and tried to start it up, but no go. I'm afraid whatever gas was left in the tank and lines evaporated or the fuel pump died of non-use/siezed. I put about 4 gallons of gas in and it still won't start altough it almost started for a few seconds once then died. My haynes manual is sketchy as to how the fuel systems works. With the key turned to on does the fuel circulate through the supply and return lines? Will it self bleed the air from the lines, how long should it take to get fuel up to the TBI? Could the fuel pump strainer maybe have gotten clogged from the evaporated gasoline gunk?

I'm changing out the fuel filter in the morning, maybe I'll get lucky with that. I dread the idea of dropping the fuel tank and removing the truck bed is not an option.

Kicking my self in the arse for not putting fuel stabilizer and additional gas in before storing the truck.

Any insight or suggestions welcomed.

[jveik]

well im no expert as i am only 17 but as far as i know unless you have an aftermarket electric fuel pump, the stock gear-driven pump wont pump gas just by having the key turned to "run." The only way to pump gas is for the engine to be turning i.e. running or just spinning when you have the starter motor making it turn over. i ran out of gas once and it did take a while for it to draw fuel up i had to pour a little gasolene in the primaries since im carbureted but i bet that a tbi unit can have fuel dumped in it too although i dont know ive never owned one so maybe if the intake is mounted sideways u can use some starter fluid or something. the fuel not getting there is maybe your fuel filter got clogged up or something or your fuel pump sucks nuts maybe. just look up on google and type in how to start blah blah blah and it will probly bring up a good site if u cant get it goin that will offer some explanation

[Wheeler88]

Thanks for the reply. I changed the fuel filter, no go, then I disconnected the fuel feed line to the throttle body. I don't have a fuel pressure gauge but I found a 2 ft. clear vinyl tube that I could thread onto the fuel feed nut and the other end into a empty beer can. I cranked her for a minute, then went for a look. I was surprised and disappointed that no gas came up (empty beer can) the line till I stopped cranking, then a small amount of gas slowly rose up the tube about 3 inchs (why?), then it went back into the line. Tried it a couple of times same thing.

Is the test I done good enough to condemn the fuel pump or am I missing something important? I still need to check to make sure pump has proper voltage. My last hope before I replace the fuel pump.

Who's the mad man that decided the fuel pump should go inside the gas tank? My guess is that it was an accountant.

[Silverado Brethern]

the fuel pump will (should) prime and pressurize the lines w/o the engine running. So turn the ket over to the point before cranking the engine and you should be able to hear the pump kick on to fill the lines. If not i would say that you most likely have a bad pump or hopefully for you a bad relay to the pump. But as is common, fuel pumps are one of those parts that wont last forever. If the pump goes prime then i would change the filter and see what that does. If still nothing you safest bet would be to take it to a mechanic to have them check it out.

[Wheeler88]

With the key turned on I don't hear anything going on in the fuel tank. I then bypassed the fuel pump relay by apply 12 volts to terminal G on the ALDL and I hear what sounds like a small calf pissing on a flat rock and I still have the fuel feed line off the throttle body and no fuel is coming out.

Could it be a bad pump relay and a malfunctioning fuel pump? I mean even though theres only 4 gallons in a long 32 gallon tank should it still make an internal splashing noise? Maybe a hose came off in the tank?

[jveik]

yeah thats a pretty wierd situation there i dunno bout that one. i dont even know if i have a fuel pump in my trucks gas tank its a 73 chevy cheyenne. i always just assumed that the gear-driven one on the side of the block was all i had...

[J-Ri]

Originally Posted by jveik

...the stock gear-driven pump wont pump gas just by having the key turned to "run."... ...but i bet that a tbi unit can have fuel dumped in it too...

The 88s have the electric fuel pump in the tank, unlike the old reliable cam&rod on block ones.
Any intake can have gasoline trickled into it. I'm sure you don't mean dump half a gallon in, but I thought I'd clairifiy that.

I'd check the fuel pressure regulator.

[J-Ri]

I guess I stopped reading half way through the thread, there were 3 more posts when I was sent back here. I'd say relay based on the fact that the pump would run with the relay bypassed. However, that would not explain fuel getting to the TB without it bypassed. Does the pump sound like it's sucking fuel right off the top of the gas? I'd try putting a few more gallons in and see if that works. The pump might just not be deep enough in the gas. The check valve in the pump is most likely bad, if the gas drains back that quickly, unless it's pumping air into the line also, and the air is floating to the top of the fuel.

[Wheeler88]

Well I got fuel problem fixed today, truck runs like a champ. I replaced the fuel pump but not the sending unit it works good enough not to spend the 180 bucks on.

Turns out the splashing sound from the gas tank was a symptom of a deteriated hose. It's a thick 2" long hose that connects the pump output to the fuel feed line. It was all soft and gummy with a 1/4" hole in the side. Hence the pissing sound and loss of fuel pressure. Also the pump strainer was falling apart after 17 years of being sumerged in gasoline. I can understand a shop charging a lot for this repair, what a pain. But definitely a DIY project if you got the time, a few hand tools, floor jack and stands or if taking the bed off is do-able thats the way to go. I have a heavy camper shell, no help and a few hundred pounds of tools in the bed.

I also replaced the fuel pump relay although I don't think anything was wrong with it cause the new one gave the same test results as the one replaced.

I learned alot about the fuel system, even learned why they moved the fuel pump to the gas tank. Case anybody cares it's to prevent vapor lock and they went to electric pumps because the mechanical pumps failed to perform well at the higher pressures required for fuel injection, well something like that. LOL
I want to thank everyone for their input. It's comforting to know that if I ran into big problems you guys are here to help.

BTW, I found this site pretty interesting and it gives a good run down of the purpose of the fuel pump relay.
http://www.misterfixit.com/fuelrlay.htm
Check out the rest of the auto repair stuff there.
Scroll down to about the middle of the page.
http://www.misterfixit.com/index.html

EDIT: tried to clarify

[Tall]

Yeah, I did the same way u did...dropping the tank...what a head ache...I think my biggest problem was I ripped the filler hose, and I didn't feel like paying 150 bucks from the dealer, so I had to bend steel reinforced hose to get it too fit (had to use a jack to bend it, hehe)...

Next time, I am just taking off the bed.