Packard Forum Index » V-8 (1955-56)

That's because your '88 Ranger has all kinds of emissions crap that recirculates the fuel back to the tank.

NO! or if it did from the factory they are not there now. I've owned the truck for 20 years and 170K miles, changed gas tank and overhauled the engine. There is no return to the tank.

My 73 Chevy i owned up until 2 years ago had NO vapour lock.

There are at least 25 country hicks around here that are driving older carbureted/mech fuel pump equiped junk i wouldn't use as a chicken coup. No vapour lock with their vehicles. No lites and no tread on the tires but they don't vapour lock.

Try to dissassemble the fuel pump and see if the two mating faces are warped. Those aged pumps have been abused, the screws holding them together have been super-torqued many times. Get the surfaces in a state of relitive flatness, then reassemble with an acute awareness of even, adequate torque, there are even small torque-measuring screwdrivers you can use, but a regular old screwdriver in the hands of someone who thinks and feels his way through will work just fine. The pump most likely has raised areas where the screw bosses are and very low areas inbetween. Introduce heat and some expansion occurs, the seal is broken and voila, the fabled "Vapor lock" occurs.

This is the first time for this on this car and the tank was over 3/4 full. It will probably be awhile before I get it back out on the road for any appreciable distance as most of the drives in the car are just a few miles every 3-4 weeks. Checking web searches and as earlier above posting, a return line to the tank seems to be a route recommended, but I sure hate to get into that and it would be a chore to do it on every car.

But I will check the fuel pump although it is fairly new and try to check all the hose clamps for tightness. It is possible, too, that I need to remove one of the filters for less restriction. I have a transparent filter at the back near the tank plus another screw-in type that goes into electric pump and that perhaps could be impeding flow a little although I use these filters on the cars and have for many years.

Where is the electric pump mounted??? Very near the tank???
Better check the heat riser. Altho drawing thru 2wo filters AND a static electric priming pump could cause the problem.

What would be interesting is to put a vacuum gauge on the fuel line and a thermometer. The thermometer would be the difficult application unless someone else knows how to add one easily.

Then, apply Avagadros law PV=T or what ever it is and maybe that would determine where and IF Vapour lock is occuring.

Well, since the original intent of this add-on electric pump was just for priming after long sits, the pump is not at the extreme rear, but alongside the left frame member but still within a couple-three feet of the gas tank; so it is back pretty far. I'll check the heat riser for funstionality. I'm inclined to eliminate the smaller screw-in filter from the electric pump inlet at this point. And the reason for the clear filter close to the tank was originally before I had the gas tank renued with the coating, so for sure one filter can come out and the screw-in is the most restrictive. In fact I had one on my '54 Hollywood years ago and it plugged up on a trip, but you had to unscrew it and saw it apart to know that.

Not as ez as flipping a switch, but fill a lighter fluid can with gas and ONLY LOOSEN the air cleaner wing nut and squirt the gas around the wing nut stem.

Most people run a battery disconnect so they have to open the hood anyway. Reach over and grab the lighter fluid can tuckd away somewhere under the hood in a good place and give the carb a shot.

For the vapour lock issue i'm wondering if pressurizeing the gas tank (2-3 psi when needed) would be alot easier to set up than running return lines, auxilary e-fuel pumps, filters and so-forth. Mite even work just fine for priming.

ANY filter prior to the pump would certainly be suspect in cases of vapor lock, as even when apparently clean they can result in lower reduced pressure (actually, higher suction) in the line which in turn lowers the boiling point of gasoline. It's a common practice to hide an inline filter in the suction line, but it's a bad practice.