Gasoline smell

[tucsonjwt]

My 83 C20 has dual tanks with vent caps on short vent hoses at the fuel sending units (no vapor recovery system.) I have always had a gas smell inside the cab since I have owned this truck. Is this normal, or can something be done to eliminate the gas smell? I replaced the vent caps, hoses, and clamps with new ones but no change in the odor. I don't see any visible fuel leaks, and the sending units were recently replaced, along with all hoses to the hard lines.
I was thinking about running extra long hoses from the vent hoses to somewhere in the rear of the truck to see if that reduces the gas smell.

[donut]

I'd give it a shot. (it's actually on my list of things to do for my truck.) Or re-connect the vapor recovery if you still have it.

[GmtGmt]

did your truck have Cats? if so are they removed?
on some cars and trucks if you remove the cat they can smell very bad of gasoline.
idk about V8s but i know from the ricers i have worked on when you do they will smell bad of gas inside the car

[tucsonjwt]

Never had cats. Never had vapor recovery system. 83 was pre-cat on heavy duty pickups and they did not require vapor recovery system either. Just wondering if this is "normal" for my stock set up. I am a little reluctant to run the hoses too far back, since my box tilts back in dump function - so I can't fasten anything to the bed - just the frame, and that might put the hoses a little too low, relative to their existing top of fuel tank position. Plus, I don't want to give the hot exhaust anything to "light off."
I might replace the fuel hoses to the filler necks, though I don't think they are leaking, and I don't smell anything coming from them - but they are hanging "loose" since they cannot be connected to the box (have to lift the box to fill the tanks.) At least I can use cheap universal hose, since prebent factory hoses are no longer needed in my application.
Stay tuned.

[tucsonjwt]

Here are some pictures of what I think is my stock heavy duty 83 pickup fuel hose setup. I get 1.75" diameter fill hose and .625" vent hose, with 5/16" fuel hose for the short vent hose with cap at the sending unit. Looks like I might need to cut a 90 degree fill hose to get the right bend to clear the box when it is in the normal down position (The fill hoses actually rest against the bottom of the bed, since they no longer go up the side of the box to attach to the fuel fill door area.)

[tucsonjwt]

Even aftermarket filler necks with 90 degree bends are too pricey. I am going to buy 2 of the generic 90 degree bends of 1.75" diameter on Amazon for about $33/pair and cut them down, and get some 5/8" diameter fuel line from NAPA for the vent lines. Then I'll tackle extending the vent caps to the rear, if possible.

[donut]

I didn't know the emissions for an '83. I also can't help with the fuel filler necks.
Maybe on the vents, a bracket bolted to the top of the frame to attach the vents? So they are between the bed and the cab. Might be enough just to get it out from under the cab. (I get the gas smell in my K-20, on warm days if I'm sitting at a light)

Also running on the assumption that the floor of the cab is tight (no holes)

[tucsonjwt]

The interior has been restored - new carpet, pad, door seals, window felts, etc. - so I think it is tight. I may have some loose grommets at the firewall, so I will have to check that out (could be the Qjet leaking too, but I can't see it). You can see the big front spring brackets bolted to the frame which obstruct the likely path of an extended vent line to the back. (I think extending the vents just a little away from the cab won't accomplish much, since that cab to bed area is already ventilated well with the space between the two.) The dump bed can slap down quite hard on the frame rails if you lower the bed with a load in it (power up, gravity down), so I think I need to steer clear of the top of the rails. I have two bump stops on the frame rails in the front, but just 1/8" rubber pads in the back. After I replace the filler hoses and filler vent hoses, I think I will temporarily run the extended vent line Christmas tree light style with zip ties until I see if it works, then fab brackets if it is a good fix. Thanks for the info.

[tucsonjwt]

I got the fuel tank vent hoses routed to the back of the truck. I also did have a leak at the Qjet inlet nut - too small to see when I checked under the hood because the fuel would evaporate on the hot intake manifold by the time I got outside the truck to check it out, and the gasoline odor also dissipated by that time. The leak finally got large enough to still be visible when I stopped the truck. I should have suspected as much since there was an odd residue on the intake manifold in front of the carb.
I routed the long vent hoses along the inside upper edge of the frame rails to the last cross member above the spare tire and re-installed the vent caps. The hoses do dip below the exit level of the vent nipple on the sending units, but there is still a strong odor of gas at the other end of the long hoses, so I assume that it is still venting OK.
No gas smell now.