ws6transam

I had fuel problems this summer that ultimately cost me my engine. The fuel was overheating and when I had half a tank or less, the fuel in the tank got hot enough that the fuel pump would lock up. This first happened when I was running below 1/4 tank of fuel. The second time was about 150 miles into a hot, sunny summer road trip, when I got stuck in traffic on I-80 near Chicago. Finally, something happened to fuel pressure with an almost full tank, and while under load, and I broke something in the engine. Probably a holed piston.

So I decided to drain the tank in preparation to store the car while saving up money to fix the engine. Lo and behold the Walbro 255lph pump seems to pump just fine again. There proved to be 10 1/2 gallons still in the tank. Only, at about gallon 9, the gas can into which I was pumping the fuel started gurgling, like I was getting to the end of the tank. A flashlight showed that the fuel pump was pumping a bunch of bubbles into the gas can in addition to the fuel. It gurgled continuously until the tank was empty. Somehow, at 9 1/2 gallon mark, the in-tank pump started to suck air from somewhere. Maybe this explains why the pump failed. Where it's getting air, I have no idea.

My fuel pressure seemed good whenever I looked at the gage at idle, with no load on the engine. My only symptom was that the fuel heats up over time when I drive until the tank is full of overheated fuel. I've bought a new fuel pump, but at this point I am not sure that it's the root cause of the overheated fuel. I think the bad pump was a result of the heated fuel. The source of the heating - maybe it's the air that is getting into the line?

Has anyone observed this when unloading their fuel tank?

84 Z-28 350

It sounds like you have a pinhole in the pickup tube in your tank, I would recommend pulling the tank and taking a look at all the lines and rubber tubing.

Also how do you know your fuel is overheating, in working these cars for 20 years or so I've never heard of overheated fuel only vaporlock which is when a vacuum is pulled on a liquid and it vaporizes but if I read right u have a pusher pump so it shouldn't be an issue

ws6transam

When I unscrew the gas cap, the hot vapors blast out. Then I notice that the filler neck is like, 125 degrees to the touch. Underhood, the braided stainless lines are too hot to touch. The pump no longer wants to spin. Then, when I toss in a few gallons of fresh gasoline, the pump begins working again.

It's definitely a tankful of really, really hot gasoline. This didn't happen when I first built the car in 2005. Something changed, and it wasn't the routing of my fuel lines or headers. In any event, now I have a damaged engine so everything has to come out anyway, including the tank. At this point, I trust nothing. I'll be looking for a crack between the pump and the sock.

84 Z-28 350

I would look at the exauast system under the tank, there is nowhere enough thermal conductivity in a 5/16" or 3/8" return line to heat an entire 16 gallon gas tank that much, something ells is transferring the heat, also how do you know there's engine damage, it takes a he'll of a lot of lean burn and RPM to damage a piston and it would have been pinging like hell prior to any permanent damage...what are your engine symptoms?