I have a stalling problem with my '79 that is driving me nuts. The truck has 142,000+ miles on it, and with the exception of a new cam & lifters, it's pretty much original and stock. The stalling occurs mostly after the truck has warmed up. Sometimes it will stall as I'm coasting to a stop or just slowing down and planning to shift into reverse. Other times it will stall as I'm going up a hill or just pulling steady on a flat road. Once it stalls, I shift into neutral and try to start it. If I'm lucky, it will start right up. Other times I have to pull along side the road and crank the living crap out of it to get it to start. I usually end up pumping the gas to get it to fire, and eventually it will start-up. It might run for 50 miles before it happens again, or it might stall in the next 5 miles. Sometimes but not all the time, it won't start until I leave up on the key.

Here's what I have replaced trying to eliminate the problem. The solid state ignition, the distributor, the coil, the spark plug wires, the ignition switch, traced most all of the wiring looking for possible shorts, made sure I have good clean ground connections, and I removed the cruise control which didn't work. All of these things have not helped the problem one bit.

Recently I was asked if it might be vapor lock. Good question, but I'm not sure if any of the fuel lines are close enough to the exhaust to get over-heated. I also wonder if I might have a faulty fuel pump (replaced about 20,000 miles ago). When it stalls and won't start, I remove the air cleaner and check for gas. I always seem to have gas when I pump the accelerator pedal. Still I wonder if I'm experiencing an old problem like vapor lock. I could try replacing the fuel pump and check for possible fuel line routing problems.

This problem started about 5,000 miles ago, and it is a real P.I.T.A. to drive this truck. My future plan is to do a complete frame off and rebuild the entire drivetrain at which time I might stumble on to the problem. Until then, I might have to park the beast unless someone can suggest where to start looking. Any help would certainly be appreciated.
Jerry

 

I have no idea what brand of ignition module you have, but I would suggest having it tested. It's best to find a Motorcraft module if that's not what you currently have. It should be mounted with 1/4" space behind it to allow for cooling. Eric (Torque1st) uses 5/16" nuts as spacers I believe. You can find the Motorcraft modules at Oreilly Auto Parts - that's where I purchased mine.

It could also be the magnetic pickup in the distributor. These failing can cause problems.

You didn't indicate whether you had changed the fuel filter, if it's been awhile it wouldn't hurt to change it. Cheap and easy to do.

 

Jason,
Thanks for the feedback. I know my module isn't spaced out at all. I'll try that first. I did replace the fuel filter about 2,000 miles ago, so I'm not suspicious of that. I'm glad you suggested the distributor. I have been suspicious of that, and I did buy another one to try. I'll get that installed too. Maybe the combination of the two will solve the problem.

I see you have a '77 with 350,000 miles on it. Looks like I have a lot of good miles left in mine.

Thanks again.
Jerry.

 

I wanted to let "firstonraceday" "Jason" know that the problem with my '79 was the distributor. I happened to stumble onto the problem while checking wiring with the engine running. When I moved the harness connector on the distributor, the engine quit. I started it again and did the same thing with the same result. Bingo I found the problem. I replaced the distributor in 2001 and have had the problem for the last 3 years. I never made the connection that the distributor was causing the problem until you mentioned it. O'Reilly's swapped the dist for a new one on warranty with no questions asked. I also spaced out my ignition module with 5/16" nuts like you suggested. It is a Motorcraft module.

I took the truck out on a 100 mile warm up cruise today and enjoyed the entire trip for a change.

Thanks you Jason for all the help on where to start looking.

Jerry

 

Threads merged. Thanks for getting back to us with the solution.