Vapor Lock, how many have had this?

[DBLSPRT68]

Hello, I think I'm having a vapor lock problem on my truck. It dosen't do it all the time, but it dies when I'm pulling a load or putting a load on the engine. After it dies, and come to a stop , I switch my dual tank switch a few times, and she'll start right back up . I don't think it's the valve, because it's only a few years old and it's a GM part. I've posted more info on the engine & drivetrain board, but only got one opinion. Have any of you guys had something like this? This truck has been completely apart, and I don't have the charcoal canister even hooked up. Nothing is factory original anymore. Thanks, David

[87 Shortwide]

We had the problem on our impala. When we'd race it, it would fall off at the finishline, and we couldn't figure it out. We put a fuel pressure guage on it, and at the big end of the track it was all the way down to around 3 lb. of pressure. Are you running a return line to get some circulation going? also, how close to anything hot is your fuel line?

[pedrofixlater]

I had this problem, it was the fuel filter clogged when at high RPM, ie pulling or racing the pressure would push the dirt enough to clog the filter. Have you gone down the road and left your gas cap at the pump???

[SSC's76]

It happend to me a few times but it never got bad enough to stop the engine.
Check the fuel filter and gas cap like mentioned. Gas caps are supposed to be changed every couple of years especially the vented type.

I cured my problem with an electric rotary pump. The electric pump keeps constant pressure in the system doesent give vapor lock a chance.

[ureckme]

I had this problem, my fuel line runs from the frame to under the right moter mount and real close to the header ( touching ) and the fuel was getting hot. I had to move the lines. Matt

[DBLSPRT68]

Thanks for the replies. I will check the fuel line routing near the engine, I still have both my gas caps(locking type), and have been thinking of going to an electric pump. Question: could engine timming have anything to do with this? It would quit when it's under a load and pulling my trailer, just wandered because this is the same driveline I had in the other truck. The only thing that has been changed is the carb and whole distributer (ACCEL HEIl I didn't check the timing setting before pulling it, and it's now set by power tuning only. I moved the timing till it pinged, and backed it off. The engine is a 350.

[KShortell]

In the first couple of years I had my truck, I had the same symptoms. I even went so far as to wrap my fuel line to insulate it. Each time, it ended up being a bad fuel pump. It hasn't acted up in about nine years now (knocks on wood)...

[SSC's76]

Originally Posted by DBLSPRT68

Thanks for the replies. I will check the fuel line routing near the engine, I still have both my gas caps(locking type), and have been thinking of going to an electric pump. Question: could engine timming have anything to do with this? It would quit when it's under a load and pulling my trailer, just wandered because this is the same driveline I had in the other truck. The only thing that has been changed is the carb and whole distributer (ACCEL HEIl I didn't check the timing setting before pulling it, and it's now set by power tuning only. I moved the timing till it pinged, and backed it off. The engine is a 350.

It's doubtfull but possible. When your hauling stuff you do create more heat and if the timing is advanced a tad too far thats even more heat to soak into the fuel system. I'd just put an electric pump (rotary style only). It will solve the problem and keep up with fuel demand better then a block mounted pump.