Fuel Problem:/

[81Scottsdale520]

So if i drive for a while during in the heat the truck starts to hesitate when at a red light and as i drove off it just died on me. is this a cause from it overheating? because i have see through fuel filters(the one right before or after the fuel pump and the one before the carb) and there was no gas going through at all. so i let it sit for a few hours(4) and i tried it again i had to crank it about 8 times to get the gas to the carb. so my question is, is this a cause from a overheat that shuts off the fuel system or is this from a bad fuel pump? or anything else. I was thinking another possibility was because i have the positive wire from the electric choke directly to the battery. so any help pleaseeeeee

[INSIDIOUS '86]

What year truck is it? You may be getting vapor lock do you have headers at all?

Fuel pump may just be Quiting to
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[81Scottsdale520]

Originally Posted by INSIDIOUS '86

What year truck is it? You may be getting vapor lock do you have headers at all?

Fuel pump may just be Quiting to
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Its a 81. and yes the original headers not sure what kind.

and that was the same thing i was thinking but i just kinda wanna make sure before i start anything.

[INSIDIOUS '86]

Well a fuel pump is $20 and cheap insurance. Not sure what carb you have but checking the filters is good. Make sure you gas cap vents as well
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[81Scottsdale520]

i have the edelbrock with electric choke.

didnt even think of the gas cap, gonna switch it out and if the problem continues ill try the fuel pump.

Thanks for the help!!

[INSIDIOUS '86]

Edelbrocls are known for percolating fuel as well. A heat sheiks or phenolic spacer can help as well
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[81Scottsdale520]

Originally Posted by INSIDIOUS '86

Edelbrocls are known for percolating fuel as well. A heat sheiks or phenolic spacer can help as well
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well the problem is before the carb, like the clear filter right before the pump was empty and wouldnt pump any gas so thats why i was thinking it was the pump or a overheat. by the way could a overheat cause that? to shut off the fuel system?

[INSIDIOUS '86]

It can cause a vapor lock condition yes. Does your fuel pump have a return line at all? Return style pumps seem to never have a issue with vapor lock.
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[81Scottsdale520]

Originally Posted by INSIDIOUS '86

It can cause a vapor lock condition yes. Does your fuel pump have a return line at all? Return style pumps seem to never have a issue with vapor lock.
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i am not sure. ill take a pic

[geezer#99]

Sounds like normal vapour lock. One way to get it to start if it dies is close the choke and then crank it.
If you keep your electric choke hooked right to your battery then expect a dead battery some day. You're creating a constant drain.

[81Scottsdale520]

it doesnt let me upload the picture. but there are 3 tubes. 1 from the gas tank where the filter is connected, the other is one with no filter or anything. and the last is the one that goes to the carb

[81Scottsdale520]

Originally Posted by geezer#99

Sounds like normal vapour lock. One way to get it to start if it dies is close the choke and then crank it.
If you keep your electric choke hooked right to your battery then expect a dead battery some day. You're creating a constant drain.

yeah battery died a couple times already so i disconnect it when im not driving, the reason i have it connected straight to the battery is because im not really sure to put it, does it have to be on when the truck is on? or does it just need to be when it turns over? and how to fix the vapor lock?

[CSGAS]

The heat in Arizona lately plus the headers' heat and the usual underhood heat is very likely to have boiled the fuel into vapor. The alcohol in today's gas does that at a lower temp than real gas.

Insulating the fuel lines or shielding them will be the most effective. An aluminum shield that also keeps heat away from the starter would be a wise move. Check to see that your fuel lines along the frame are not too close to your exhaust pipes, too. Shields work there too.

The vented cap is very important if someone ditched the charcoal canister somewhere along the way. If you do still have the charcoal canister, check it to see if the filter in the bottom is clogged as a hint to the condition of other filters in the system. Make sure none of the lines to or from the canister (or the rest of the system for that matter) are swollen shut (will feel "spongy" on the outside) or bent too tightly so they are cutting off flow.

Check your oil for the smell of gas. If the gasket or seal between the fuel pump and interior of the block is torn that will be the result. The diaphragm inside can still go bad without that symptom. If you have to take the pump off, using a long bolt to hold the pump pushrod helps to keep it from getting too far away from the motor

Good luck, and don't think too much into it. Just check one thing after another analytically. There's nothing you can take off that you can't put back on again--with directions and the right gaskets or bearings of course.

[geezer#99]

Get the power for your choke from the fuse box. Likely a couple unused spades there that say unfused on them.
Vapour lock cures.
Use steel line, not rubber from the pump to the carb.
Metal filter not plastic.
Put filter as close to outlet of pump as possible.
You only need one filter.
Advance your timing on your motor. Try 12 degrees initial. Retarded timing causes heat.
Use a vented gas cap.

[81Scottsdale520]

Thanks guys helps alot!!
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[kjc292]

CSGAS you mentioned about a vented fuel cap. Now the PO for my truck ditched the charcoal canister. My truck is sluggish and when I step on the gas it will cut out or back fire sometimes. The gas cap is the one with the locking key, how do I tell if its vented?
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[INSIDIOUS '86]

Try driving with the cap loose see if that fixes any issues. If not then I would look further on down the system
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[CSGAS]

the sluggishness and backfiring is the acceleration pump in the carb not working. Usually the pump cup dries up and won't seal especially if it's been sitting dry for a long time. I had to repllace my own yesterday.

See if a blue cup (synthetic) is available for your carb from the local parts store. They stand up to alcohol a lot better than even the coated rubber ones that come in today's kits.

Another sign that you are already vented somewhere is that a sealed system would start out OK then gradually get harder to pump fuel to the carb because it is fighting the vacuum in the tank. That would stall the engine then you can restart after the vacuum is slowly replaced by air. The cycle would continue over and over.

Loosening the gas cap one notch and seeing if it makes a difference like Insidious said is an absolute test, because it breaks that seal. Scottsdale, if you can't do anything else to fix the situation, if you have a sealed system, then go ahead and cut out a part of the seal on the gas cap near where the cut portion would be pointing up when fully closed.

Canister equipped vehicles had a rubber line going to the tank that also served as vapor recovery. Either that hose is still hooked up on KJC's without a plug or someone connected a small breather filter (K&N, Spectre, whatever, it'll look like a high performance rear end breather) somewhere.

[kjc292]

CSGAS im hoping its not the carb, just bought a new one that had a defect in leading to leak gas, then returned and got another. if thats the problem im ditching the one barrel 1m rochester and going with a 4barrel. sorry for bumping the thread.