gas leak!!! crap on a stick

So I went to fill up the OCC for the first time tonite (came with 3/4 tank)

The gauge says tween 1/4 and half, but I had it stall on me twice making turns (they were a little fast, but still) so I figure it's the old B-body gas gauge trick (my 92 says 1/4 of a tank it'll stall on low speed corners but still will only take 17 gallons or so).

I start pumping and it's coming out slooooooooow and the darn pump keeps shutting off. I get annoyed and move to another island at the station.
I start again and it's the same. I start to wonder if a vent line is clogged or something. So about 10 minutes later I'm at the 12 gallon mark (first pump of 2 gal plus this 10) and the pump keeps clicking almost immediately. I keep topping off, figuring I have 3-5 more gallons to go in.

So finally I notice gas on the ground and stop clicking the pump. I look under and gas is pouring off the tank. Best I can notice it must be coming out of the top and running over. I hop in the car and drive out of the station into a parking lot nearby. The leaking subsides fairly quickly and I go into the store. It's not leaking anymore, but why did it leak?

I know the tank should be sealed. Only thing I can think of is the one vapor line that goes to the sending unit is missing a clamp and it's leaking there. Going to have to get under there and see what's up.

Hence this post.

Where would you look first????


Not to jack my own thread, but why do the TBI cars seem to fuel starve on a 1/4 tank???? Do the earlier tanks have the same baffles and the LT1 tanks???

Could be a line, or the top of the sending unit itself. That rusts out on cars in salty areas (speaking from experience).

You'll know as soon as you drop the tank...

jayoldschool wrote:

Could be a line, or the top of the sending unit itself. That rusts out on cars in salty areas (speaking from experience).

You'll know as soon as you drop the tank...

like I didn't do that enough last weekend........grumble grumble...I don't think so though as although the car was registered in Tenn, it was only there less than a year....
we shall see on the next empty tank I guess.

I don't think I have ever had the 92 RMW low enough to stumble. The low fuel light comes on so early, it gets terrifying to drive with it mocking me. After the light comes on, it will only take 15 or 16 gallons, so there is still a long way to go before it stumbles...

Sprocket wrote:

Where would you look first????

for some matches,.....

nick

Based on your description, it sounds as if your anti-syphon valve is lodged in the closed or partially closed position or your fill vent is plugged or some combination of both. Would also suggest either your sender unit or one of the hoses is leaking. Don't think the two problems are related. I have had two TBI tanks out and have removed the anti-syphon valve from both. Makes a big difference in filling the tank.

Can't see the baffles being different between the LT1 and the TBI. Would suggest both will become silent especially in right hand turns.

Bill

thanks Bill. I've only run about 50 miles on the tank so far and it's still coming out (from sloshing while driving) as it's slightly dripping when I get where I'm going but then it stops (not a constant leak). I'll be dropping the tank when it gets low. I do have a 92 Caprice tank and sending unit from Ruby (put a RMW tank in just after I bought it).

i,ve had this sort of problem,. one time it was the return line only leaked when the car was running,.,. the hose from the filler neck on another,. and one had the sending unit completely rotted out on top,. took a pile of jb weld to fix 'er.
JB weld Is your friend,.

Nick
certified master JB welder.

finally had a day off when it wasn't raining and dropped the tank.
I had two cracks on the top driver's side front corner.

I didn't see 'em until I tipped the tank up to drain it into a gas can and then it came out the cracks. ended up punching a hole in the tank to fully drain it, as I wasn't going to use it again.

Luckily, being a wagon hoarder, I had an extra tank handy (it originally was in Ruby).
Car runs better now that the tank is sealed.

crack explains:
why the fuel pump would shut off (escaping vapors)
why there was no vacuum when I would unscrew the gas cap.


On a side note, having dropped both an LT1 and TBI tank recently, the LT1 tanks have more baffles in them when you look in from the top which I had suspected all along anyway with the sloshing fuel starvation on a 1/4 tank.

When I dropped the tank yesterday I got between 6-7 gallons out of it and it was starving on even moderate cornering (10-15 mph)....

Now that it's all sealed up again, I should see a little improvement in mileage as I'm not letting it evaporate, lol.