No Fuel Shutoff

[truckster]

I just got my Blazer back on the road, and it has a problem with fueling. The fuel shutoff on the pumps doesn't work, at least not until it's puked a fair amount of gas on the side of the truck.

I replaced the charcoal evap canister and a broken evap line under the tank. It was doing the same thing 8 years ago when I parked it. Any thoughts?

[SeventyOne]

Originally Posted by truckster

I just got my Blazer back on the road, and it has a problem with fueling. The fuel shutoff on the pumps doesn't work, at least not until it's puked a fair amount of gas on the side of the truck.

I replaced the charcoal evap canister and a broken evap line under the tank. It was doing the same thing 8 years ago when I parked it. Any thoughts?

Fuel shutoff on the pumps? Fuel pump? Can you tell us more about your set up?

[truckster]

I go to the gas station, pull up to the pump, put the nozzle in the tank, and it doesn't shut off when it should. It's a stock tank with stock plumbing.

[72gmguy]

You could check the vent on your tank. Or maybe some collapsed lines either in the vent or even the fill hose. Ethanol fuel does not like old rubber fuel lines.

[DeadheadNM]

FWIW I experience the same in my K20 and the Blazer. I blame the pumps

[truckster]

Originally Posted by DeadheadNM

FWIW I experience the same in my K20 and the Blazer. I blame the pumps

If YOUR Blazer has the same problem, I don't feel so bad.

It wasn't so bad until they built a car wash next to the Costco where I fill up. With the car dryer going all the time I can't hear the sound of the tank filling and shut it off in time. I guess I'll have to fill up early in the morning.

Thanks.

[DeadheadNM]

Lol! I baby sit the filler and often kick myself for trying the add that last bit that inevitably burps onto side of the trucks.

[pound41]

I have owned 3 other blazers and never had an issue. The 71 I have PO changed the tank and didn't swap the neck off old tank. It has a hose that has just a little bit of collapse
in the hose. It will not shut off at gas pump.

[SeventyOne]

Originally Posted by truckster

I go to the gas station, pull up to the pump, put the nozzle in the tank, and it doesn't shut off when it should. It's a stock tank with stock plumbing.

oooh the GAS STATION pump. Thanks for the clarity.

Mine shut off properly at the pump. Fresh tank and lines/hoses 1 year after restoration. It would be my guess that tank pressure from filling is leaking out somewhere and not activating the auto shut off correctly.

[DeadheadNM]

My tank is a reproduction with an OE neck and joined to a NOS GM hose with an OE filler neck. The gas pump will stop but it's as if there is turbulent flow at the end that lets a small amount splash out before the flow ceases. The same happens in my K20, which has its original gas tank.

[SeventyOne]

Originally Posted by DeadheadNM

My tank is a reproduction with an OE neck and joined to a NOS GM hose with an OE filler neck. The gas pump will stop but it's as if there is turbulent flow at the end that lets a small amount splash out before the flow ceases. The same happens in my K20, which has its original gas tank.

Have you tried using the slower setting on the pump's lever?

[DeadheadNM]

Yes, that's how I typically fill. I still baby sit the fill and close it out manually just to avoid the potential clean up. I do like the smell of gas though

We are fortunate here that stations carry 91 octane ethanol free as the premium option and some also offer an 89 octane ethanol free choice as midgrade.

[K5Fan]

A gas station pump will shut off when the 5 or 6 gallon tank for your mower, or whatever is full. Same with the fuel cell for boats.

Chris.

[franken]

I'm curious about how gas station pump shutoffs work. My 2004 truck has issues w/ gas pumps shutting off and always has. This happens less if pumping slowly, but may still happen on the slowest setting. My theory is the truck tank vent is pinched but I can't say. If I turn the nozzle upside down it won't shut off at all, but of course I have to listen and stop it myself.

[K5Fan]

It's based on the pressure that the gas station pump feels. There is some kind of valve or diaphragm in the pump handle. I don't know about 2004s but newer vehicles have some kind of sensor in the vent or ecco system. When that goes bad somehow it tells the pump that the tank is full.

When it pukes gas before the pump shuts off, I wonder if that would have something to do with too much ventilation? When you fill up a 5 gallon tank, the pump shuts off, but only when the gas reaches the end of the nozzle. Maybe today's gas pumps are set to sense a higher pressure? When your tank shows that it is full, from what I understand, the tank is only about 80% full, right?

My 70 K5 drinks so much gas that one time I left it running when I was filling it up, and the pump never stopped pumping!!

Chris.

[K5Fan]

Ah, now I see where SeventyOne addressed the pressure thing. Did gas come out of the gas station pumps faster in the 70s?

[awelle01]

I have also experienced the same issue from time to time.

I have stock filler neck, but swapped out the tank to a larger one from a late 80s/early 90s so could add fuel pump assembly for LS swap

[mister.freeze]

I always thought the trouble was from the filler neck being too narrow. When the tank is full, the neck fills up too fast to stop the pump in time. That and the little side vent isn't far enough down the neck.