maiden voyage- FAIL!

[HalfTon]

Well today was supposed to be the day my truck was to make the 15 mile journey home. The truck was at my grandpas shop were ive been working on it for the past few months. I had driven the truck up and down the road a few times around the shop but not very far and it seemed to run good. So this afternoon I went and fired the truck up, checked everything over and all was working as it should. I had a relative follow me just in case something did happen. So I left the shop happy as can be, got on the highway for about 1 mile and all the sudden it started sputtering so I pulled off the highway and saw the gas gauge was on empty. It had more than a 1/4 tank when I left. So my relative went and got a 5 gallon gas can and filled it up. Once all 5 gallons were in the truck I knew I had plenty of gas to get home. The truck started up just fine and drove good for another 1/2 mile on the highway were it started sputtering again while goin up hill, so I pulled off the the side and sat there trying to start it for a good 20min, I rolled back down the side of the highway to were it was more flat and it started back up again. By now I knew it wasnt goin to make it home so I turned around and started back for the shop. Then while on flat ground it started sputtering again and died at every stop light. I was pissed at this point and finally sputtered and chugged its way into the shops parking lot. What could be causing this? It ran fine when I test drove it and never acted like this?

[70-Shorty]

check your fuel filter(s) or your sock filter on your in-tank fuel pick up.
Tim

[71swb4x4]

If you ran it close to empty you probably sucked in every piece of sediment and debris that was in the bottom of the tank. Replace all the fuel filters and try again. Make sure you have a good inline fuel filter and check the carb, some carbs have fuel filters just inside the inlet.

[HalfTon]

I have one fuel filter before the fuel line goes into the carb, there was some flaky rusty looking stuff in there, is all this crap in the tank? If so, whats the best way to clean the tank? Also, if it afftects anything or not, the tank was moved under the bed by the PO

[71swb4x4]

If it's under the bed take it off and clean it out.
In the meantime change the fuel filter and start it up. If it fixes the stalling problem you know you have found you8r problem, but be prepared to lose another fuel filter.
Are you sure there isn't a filter in the carb? It's a cup shaped wire mesh filter.

[HalfTon]

Yes, there is one in the carb. Ill check that one too, and clean it of any debris.
thanks.

[71gmcburb]

my 68 t-bird with 429 4bbl and 71 burb with 350 4bbl both have 2 lines on the carb 1 incomeing and one return line to the tank. i would check to see if both are connected right and for leaks if all is right is your pickup tube low enough in the tank? just a thought as you stated th PO installed a underbed tank

[HalfTon]

There is only one fuel line on my 4bbl holley and im positive there are no leaks. Im thinking the pickup in the tank is part of the problem too, could it be possible that maybe the PO put the pickup in the front of the tank instead of in the rear?

[dmack91]

I wouldn't think the pickup tube front or back would make that much of a difference (uphill or downhill).

Another thing to check is that the tank is vented properly. If it dies, open the gas cap. If there is a whoosh/sucking sound of air being drawn in quickly, it is pulling a vacuum and starving for gas while running. Vented cap or vent line is required.

[MikeyMan]

Bet it's the ol' crusty fuel tank. Had a similar issue.

Truck had sat in a garage for a couple years. Put a new crate motor in it, running great.
Fill the gas tank for the first time, now runs like crap. Pull the filter at 2bbl carb and it's loaded with rust.
Ended up removing the behind the seat tank and having it cleaned and coated by a pro shop. Lifetime warranty too. Added an inline fuel filter to go along with the carb one.
Everything was fine after that.

Also check any rubber fuel lines, they can deteriorate or become soft and collapse and pinch off your fuel supply.

[MARKDTN]

I had a '71 Eldorado that acted like that. Replaced the fuel pump, filter, rebuilt the carb. It turned out to be that there was so much gunk in the fuel sending unit that it could pull enough fuel to idle, but after you drove 1/2 a mile it would starve for fuel. My advice is clean the tank, replace the sock and filters, and make sure the lines are clean.

[fast50ranger]

Clean or replace the filters and enjoy your truck

[FLDBRED]

How old was the gas in the truck? Bad gas can make it run like that.

[webfoot]

There is probably a bunch more of that crud at the bottom of the tank. if ya don't clean it out you'll be putting up with this for a looong time.

x2 on checking the sender and inspecting/replacing the fuel pickup sock.

[D.PASSMORE]

In the shop -did you make any MODs to the motor? Running stock ignition? Tell us more...

I had a simalar issue: ran fine at the beginning but once it heated up - sputtered/backfire a little. Used the wrong gasket on intake manifold. So, when everything expanded (heated up) it would start sucking air around the gasket. Drove me crazy for a while...

[57larry]

I'd clean the tank out and replace all filters

[C20-67_N_MO]

Sounds like you guys are on the right track on telling the OP the problem. I would drop the tank and clean it out. And make sure the pickup sock is in place and not filled with rusted gunk.

Good luck.

[Ackattack]

I agree with everyone else, one other thing I'll throw out is: is the floats set right in the carb?

I'd check the filter, sending unit first, but that might be something else to check.

[HalfTon]

Ill be checking everything you guys mentioned tonight. And for the floats be set up, Im not positive, we got the carb from a friend and he said it was good to go and it never acted up when it got up to temp when testing. The motor is a 355 built by a local shop: 9:5:1 compression, comp 292 cam and lifters, 1.5 roller rockers, weiand stealth intake. Thats all I can remember off the top of my head, ill have to look at the build sheet of the motor. It is running HEI ignition too.