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With ambient temps at 85+ degrees or long runs, I have a severe vapor lock problem. I have changed all fuel filters (3, 1 in carb, 1 for each tank). I have added an electric fuel pump at the tank switching valve. That seemed to help slightly, but still a big problem. I am thinking that mabey eliminating the mechanical pump might help by eliminating fuel heating in the pump. The pump does not have a return line. Any Thoughts?
Thanks, Ron
Hi i would try replacing the gas cap for starters and check your vent tubes on tank.make sure you use a good brand fuel filters, i change my chasis fuel filter once a year on my motorhome. do you have a carb or throttle body, your injectors maybe clogged or if you have a carb maybe you need the carb overhauled, well good luck
Lots of back yard fixes for this problem. I am suprised that your unit does not have a return fuel pump on it because that would virtualy eliminate the problem. My 78 did. Maybe check to see if someone has put a cheap will fit on and eliminated the the return line. Hopefully you could put it back in service. Insulating the line from the tank all the way to the carb was how this was fixed in the sixties. (no I'm not that old, but one of my trucks was). Heat sheilds and air flow rerouting has worked on a few. I personaly would check to see if there was a return system from the pump and either build or repair this system first. Good Luck
RON, TRY RUNNING WITH YOUR GAS CAP LOOSE. OR WHEN YOUR ENGINE STALLS, OPEN THE CAP SLOWLY AND SEE IF IT SUCKS AIR. A TANK THAT CAN'T GET AIR WILL CAUSE VAPOR LOCK. AND THE HOTTER THE BETTER THE RUBBER WILL SEAL AT THE CAP. IF THE TANK IS NOT VENTING A OLD COLD SEAL WILL LEAK ENOUGH AIR IN TO ELIMINATE THE PROBLEM. RICH
RON,SORRY I'M SO LONG ANSWERING. PUMPS AREN'T USUALLY A HEAT SOURCE, UNLESS THE EXHAUST IS HEATING THE PUMP HOUSING. MOST OF THE OLDER ENGINES WITH VAPOR PROBLEMS HAD LINES ROUTED OVER THE EXHAUST MAN. OR THE CARB. SAT OVER IT. KEEP YOUR LINES AWAY FROM THE BLOCK AND BEFORE YOU SPEND A LOT, TRY RUNNING THE FUEL THRU A SMALL AUX.COOLER. SOME OF THE 70'S CHRYSLER PURSUIT CARS HAD COOLERS ON THE TRANS, POWER STEERING AND FUEL LINES. RICHARD
Rich, Thanks, I'm going to try that, because that is somthing that would be very easily overlooked. In 1976 chevy did not have a return line from the pump. They didn,t offer a 454 in a K10 4X4. I built and installed mine. In order to use a mechanical fuel pump, I had to use a 1966 396 Chevelle fuel pump because it was short and used no return line. The front crossmember in 1976 did't have clearence for a normal 454 fuel pump because it was not designed for a 454, Daa! What do you think about elimating the mechanical pump, for the heat source, and going with an electric pump only, with a oil pressure switch of course?
Thanks, Ron
email Ronald E. Cannon
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