Filling up at the pump

[MEMO43]

Ok this one has me baffled and frustrated, here is the issue
I don't recall ever being able to go get gas with out having the constant resetting of the gas pump.
76 k5 with a 31 gallon tank, I replaced the sending unit, new one has 4 outlets
1: to the vent tube at the fill neck
2: feed
3: vent line running all the way to the engine compartment
4: capped off thinking of adding an additional filter/ vent
the issue has gotten worse with ever since I replaced the engine,
I am using a parts store locking gas cap, that I have drilled for venting purposes.
I have checked the vent hose going to the fill tube for obstructions and came up with nothing.
I don't want to drop the tank just yet (cutting access panel maybe)
I am not building up pressure with the current cap (even tried the old non locking cap same results)
I have tried different gas stations, different style fill pumps.
holding the pump side ways, upside down, even sticking the tongue out. I cant for the life of me feed the beast.
any pointers, ideas, recommendations shy of replacing all the rubber lines or adding an additional vent.
I will try and get some pictures up next chance I get

 

[76zimmer]

I’m not sure if 76 had it or not but perhaps the other line goes to the charcoal canister by the core support?

 

[MEMO43]

it never had a charcoal canister when I got it,
the po switched the front clip (doors, fenders, grill & hood) to a 91 suburban.
the hose that goes to the front vents by the radiator
maybe the vent hose is to long?

 

[TuckerK5]

Mine is the same way. All new hoses. Boyd tank. I have to sit and hold the trigger just barely on.

 

[ktmoutfront]

It's the fill hose. Look for a narrow spot in it.

 

[obijuank5]

In 79 or so we all switched to unleaded gas and got new shapes of fill nozzles on the pumps. It's just new pumps old filler necks.

 

[Babaganoosh]

Turn the nozzle side ways and you can get full speed, at least it works on mine.

 

[MEMO43]

I'll try an look at all the recommendations
Babaganoosh I've tried holding the nozzle every which way to to include stinking my toungue out.
Even just barely having the nozzle in
I've even thought about using a funnel
But I don't want to go the bandaid approach
More like the a stich approach

 

[bp71k5]

Mine would do that when I had a low spot in the big vent hose that goes to the filler neck. Both the fill hose and the big vent need a clear straight downhill shot to the tank. Otherwise gas back up in the fill hose and shuts the pump off.

 

[tenderfoot]

This wouldn't happen to be at shell stations would it? I have this problem with GM work trucks at shell.

 

[76zimmer]

It sure sounds like a fill tube or a venting problem.

 

[rampage]

How did you test the vent tube for obstruction? If it’s swollen then you might be able to blow through it but it might not be able to handle higher volumes
Try pulling back the rubber vapor recovery nozzle on the pump and see if that helps. Or you can put a fuel filter on the extra outlet and run that up some place high to test if the pumps are producing too much pressure in your tank.

 

[ktmoutfront]

How did you test the vent tube for obstruction? If it’s swollen then you might be able to blow through it but it might not be able to handle higher volumes
Try pulling back the rubber vapor recovery nozzle on the pump and see if that helps. Or you can put a fuel filter on the extra outlet and run that up some place high to test if the pumps are producing too much pressure in your tank.

Vapor recovery nozzle. That's funny. Haven't seen one in years.

 

[MEMO43]

This wouldn't happen to be at shell stations would it? I have this problem with GM work trucks at shell.

I've tried several gas stations from chevron to 7-11 even the ones without the vapor recovery system. They all do the same.

How did you test the vent tube for obstruction? If it’s swollen then you might be able to blow through it but it might not be able to handle higher volumes .

I removed the end fitting brass fitting that vents into the open air
I think I'm going to shorten it an attach a fuel filter to act as a vent close to the tank itself.
Vent cap similar to those that are found near the axles

 

[1-ton]

I have a similar problem with my truck. It has new saddle tanks, senders, pumps, filler neck, vent hose, and EVAP canister/hoses. I have to hold the pump handle up at an angle to get the fuel to flow. I think it is because aftermarket filler neck hoses are manufacture at a tighter angle than the factory ones where, thus the fuel splashes off the back of the filler neck hose, and causing the pump handle to have have to be held at a weird angle to keep the fuel from splashing back up at the fuel pump handle fume sensor.

 

[diesel4me]

I think its the nozzles at the gas stations more than the truck's fault--some I fill up at shut off wicked easily,like one drop splashes back and "CLICK"..it shuts off,and you'll have to re-start again many times,I find barely pulling the trigger so the flow slows down helps prevent that..many stations don't keep their nozzles up to par,and are probably adjusted too sensitive to prevent spillage..

This happens with both gasoline and diesel fuel,its been an irritation on many vehicles I've owned over the years..
Some nozzles still have vapor recovery "boots" here,some don't..
I think the boot only prevents you from getting fuel on you when it splashes back more than anything..

Some of the places I fill up my diesel at are ones big rigs use often,and their pumps are a super high flow,I have a hard time filling my tank at those places without it shutting off multiple times..the pumps are designed to fill a 150+ gallon tank quickly..they overwhelm the filler vent on my truck..you must barely pull the trigger and let it trickle in..
One station has a separate diesel pump for cars and pickups,and several others in a larger area for the big rigs with high flow pumps..

Other stations pumps, I can hold the trigger wide open and it'll not shut off until diesel gushes out onto my pants!..

Since my truck doesn't have this issue at every gas station,I tend to blame the pump nozzle..

 

[red EOD]

Have the same burping fuel problem with my crew cab at the diesel pumps. Stock saddle tanks did it, going to the 40 gallon suburban tank had the same problem until I cut a hole in the bed floor giving direct access into the top of the tank. The newer fuel pumps flow faster and require a straighter/larger diameter path for the filler neck.

 

[MEMO43]

Far left vent tube to filler neck
#2 vent by fill3r neck
#3 feed
#4 additional vent line

I will be using 2 of this go fast filter to help venting the tank

 

[MEMO43]

still at it, I took the sending unit out to see if something was blocked, clogged
the sending unit vent (never knew I had one) the check ball was clogged,
removed it an put all new rubber hoses for the vent tube, and filters that are acting like vents
put the trap door back in
went to gas up
and the dreadful click???
I don't recall having this issue before. I have tried 4 different gas stations and still the same
all that is left to replace is he filler neck (not blocked)
gas tank ( not leaking an clean on the inside
do the tanks have some sort of flap on the inside of the fill neck.
the temps have been in the teens
maybe the exhaust is does come over the axels.

 

[K5wrench]

The m1008 and m1009 CUCV's like mine came with a large "funnel" style filler neck.
I can fill up at the high speed diesel pumps too.
Could this help?
The down side is there's no locking cap avaliable that i can find.
Could make a locking gas door.

I found these fill necks for sale on popular internet auction sites.
They are really huge at the cap, but neck down to standard GM fill pipe size towards the rubber connection to the tank.