Every Time I Get Fuel!!!

[LuckyHenriksen]

Every time i go to the gas station and fill up, the truck wont start. My tank is mostly empty, and I usually put ten gallons or so in. Is it some kind of vapor lock? Its a major PITA that turns an 8 minute fuel stop into a half hour embarrassing ordeal. Why is it doing this and what can I do to fix it?? Help please!!!

[67ChevyRedneck]

What's it doing?


Does it do nothing when you try to restart it? Like absolutely nothing, or even just barely clicking? If so, the starter/solenoid may be heat soaked.

If it's doing that, you may need a new starter and you need to put a heat shield on the solenoid.

[68gmsee]

Can you give a little more info? Like does it do this only when you have to get gas? In other words, it never has this failure until you have to put more gas in it?

If that's the case, it may be a filter and/or fuel pump issue. There may not be enough suction from the fuel pump and if there's restriction in the lines or filter it will have trouble suctioning gas. To check, you can carry a small fuel container and pour gas in the carb to see if it starts that way.

If it does it at other times after a stop, like when you go into a quick stop, then it could be flooding. That's the main problem with not starting after a quick stop. You can check that by looking inside the carb throat or having someone look at the exhaust pipe when you finally get it started for black smoke.

[LuckyHenriksen]

Sorry. In my frustration I wasnt writing clearly. I crank the starter and it just cranks over and over and over. Like theres no fuel going to the carb. And then after fooling with it for a while I just keep pumping the gas and finally it starts to catch and I have to keep it planted to the floor and it stumbles and coughs to life. And it only does this when I get fuel, any other time it starts right up

[cdowns]

if you're running it close to empty then pumping gas into it you're stirring up all the old crud thats in the tank from the past 40years//next project should be take out tank and clean it

[67ChevyRedneck]

I revise my guesstimate to be a dirty fuel tank/filter/carb?

[LuckyHenriksen]

Well the carb is pretty beat, but it has to stay for now. I will check the lines/filter, they are probably nice and filthy. Cleaning the gas tank sounds like a good plan. Is it fairly simple? I really want to relocate it but dont have the funds right now. Thanks for the advice. If I always keep it at least a quarter tank full will it not have this problem?

[dwcsr]

If you have a 3 line fuel pump block off the return to the tank. It may solve your problem. The return was a failed attempt to stop vapor lock in the pump by circlulating gas thru it. It didn't work so it not needed.

[PanelDeland]

It may help to keep a 1/4 tank in it but you really need to be running a good inline filter and carry a spare.The crud in the tank will eventually work it's way out and into the filter but you will be replacing filters in a lot of places.And if the sock or inlet filter in the tank is dirty and doesn't have a hole in it you will probably have the same problem.

[LockDoc]

Originally Posted by LuckyHenriksen

Sorry. In my frustration I wasnt writing clearly. I crank the starter and it just cranks over and over and over. Like theres no fuel going to the carb. And then after fooling with it for a while I just keep pumping the gas and finally it starts to catch and I have to keep it planted to the floor and it stumbles and coughs to life. And it only does this when I get fuel, any other time it starts right up

Next time it does it don't pump it. As soon as you turn the key to crank it push the gas pedal all the way to the floor and hold it there until it starts. I think it is flooding, and pumping it makes it worse. I could be wrong so If that doesn't work try pouring a small amount of gas in the carb before you try to start it as 68gmsee said. I'm not sure what putting gas in it could have to do with it other than what cdowns said.... There is a strainer on the end of the pickup tube inside the tank that could be plugging up but there should still be enough gas in the carb for it to start it just wouldn't keep running. That's what makes me think it is flooding... That's what my '39 Ford with a 350 Chevy engine was doing. The needle valve was bad and the residual pressure in the fuel line was pushing the fuel past the needle valve and forcing the gas out of the float bowl into the engine flooding it while it was sitting.

Sorry about the novel...

LockDoc

[Rooster's 67]

Lucky,

In your second post you stated that you have to pump the throttle repeatedly then when it starts to cough and sputter you hold it on the floor. is this correct?

if that is so, holding the throttle on the floor would act to lean the mixture enough to allow it to crank.
I suspect that the engine is flooding while sitting.

Does the truck missfire after it starts?

again is this only after fueling or does it happen after running into the convienence store also?

I dont doubt that there is crap in the tank, however the carburator bowl should have enough fuel in it to crank the truck.
normally debris in the tank will get sucked up against the sock in the tank causing a restriction, but that will cause a fuel starvation issue while running generally under a load or under higher fuel requirements. but wont affect cranking unless the bowl was low on fuel upon shut off.

Does your gas stations use the vapor recovery bellows on the nozzles? these could possibly cause excess pressure in the tank while fueling causing the carb to overfill the bowl.

what kind of carburator is on your motor?

[LuckyHenriksen]

Wow thanks for all the responses guys. No, my fuel pump is a cheap one from Napa with two lines. Where is the filter in the tank? Is it hard to check it? I was also curious about just matting it and hoping it starts. I will have to try it again. It doesnt take long to burn through a tank of fuel =( I was curious about it being flooded. It seems like this could be my problem, but it only does it when I stop and have gas pumped in. The idea of crap swirling around and clogging up sounds like another good one to check. No, any other time it will crank right up after I make a stop. And about the gas nozzles having vapor bellows, I have no idea. how do I find out?

Oh I have an old 650 Edelbrock

[Rooster's 67]

the nozzles look like this

[LuckyHenriksen]

Ummm yes they look like that but the black part isnt that long. What does that do exactly?

[IvelDesigns]

i'm guessing it keeps the gas fumes in the tank. but if sealed well on a tank with no vent, it could build pressure, possibly flooding your truck.

i'm taking a stab in the dark here. someone else will speak up

[68gmsee]

The sending unit suction tube is stationary. The only thing that moves up and down is the rheostat float. So, the running it low wouldn't necessarily introduce more junk in the lines. However, it is possible to stir up the bottom partcles.

The flooding it is a possibility. Easily checked.

The fuel starvation (reason for putting a small amount in the carb) is usually caused by restricted flow from either filters, clogged fuel lines (happened to me) and/or defective pump.

Again, the pump operation is easily checked by removing the line into the carb and placing into a clear plastic container. You should get a good, pulsating stream of gas coming out.

The sending unit sock is internal in the tank and you have to remove the sending unit to check it. Be aware that if it's never been messed with, it probably is brittle and will break off. I left mine off and installed an external fuel filter before the fuel pump.

[LuckyHenriksen]

I will start by checking all the external lines and filters, hopefully something will come up. It just seems weird that it only does this at the gas station Thanks for all the info guys and feel free to give me more advice

[HomerJ]

If you drive your truck, then just remove the gas cap (but don't add fuel), do you get the same results?

It sounds to me like it's flooding. Could it be that driving it creates a vacuum in the tank that the fuel pump can overcome, then when the vacuum is released, fuel is forced past the needles and seats to flood the carb?


Just a thought.....

HomerJ

[LuckyHenriksen]

That is quite possible. Im sure it is something to do with air/vacuum lock, because it only does it at the gas station. It seems unlikely that it would build up pressure though, cuz the gas cap doesnt seem to be air tight. When it is flooded, what do I do? Just wait for it to drain back?

[70rs/ss]

Put the pedal to the floor and crank it, it'll spin a few times then should start to catch and run. The sock is a great place to start, because they get brittle and plugged up, but that would be starvation, not flooding, try the pedal to the floor bit the next time, if it starts, then it is a flooding deal, check the float in the carb as well as the needle and seat, a rebuild may help out there as well.

[LuckyHenriksen]

Ok ill try the pedal-to-the-floor trick. And I think I need a new carb, or a rebuild, cuz it doesnt seem to be opening all the way

[kcjones]

After reading all this, a few thoughts: It's almost definitely not a starvation issue as the fuel in the bowl won't drain back through the pump and lines. If it were a clogged line/filter/sock, it'd rear it's ugliness after running for a few seconds/minutes, when the area that is clogged causes new fuel not to be delivered to the bowl. The fuel in the bowl should last a little bit, though, especially at idle. One way to be sure it's not starvation is to just look down the carb when it's not running (safety first!), right after you've removed that gas cap. Give a quick jerk to the throttle. You should see the accelerator pump squirt fuel into the carb- and that will tell you you can rule out sending unit sock, fuel filter, lines, pump.

I'm saying flooding, too.

[68gmsee]

Good points... But, all of this would make more sense if it happened other than when filling up. Even the flooding should happend anytime the truck is stopped for a short time.

The only thing different is that the gas cap is removed and fuel is introduced into the tank.

Try to eliminate all possibilities before removing the fuel sending unit. That can be a pain and may not work right after you take it out and reinstall (which is also a pain)...

[68gmsee]

Forgot to mention.. After you check all of the possibilities and if you feel it is vapor lock try to see if you can push the truck out of the way and let it sit until it cools off for a while. Maybe the 30 minutes that you mention.

Also, see if the fuel line is too close to the block somewhere and maybe place some sort of shield on it.

[LuckyHenriksen]

Well I decided to run up to the local NAPA and sniff around for some parts, and I parked the '68 out front for maybe 10 minutes tops, and the same thing happened. I just kept my pedal to the floor, and it struggled, caught, and finally roared to life. I just kept my foot down the whole time. Now I know it isnt just fuel stops. Sometime this evening I will pull it all apart and see what the filter and lines look like. Would there be a problem with the carb I could check too?