Hello,
I have a 1978 D150 with a stock 318. It is my yard truck I use to plow my driveway and living in Vermont I really need this truck running. Ok so here’s what’s going on. The truck starts right up, and I start plowing then after 10 -15 minutes it will stall here and there, but the more I drive the worse the stalling gets, to the point I can’t go more then 10 feet without it stalling, but it always starts right back up. And the truck in not overheating.
Work I have done, at the end of last year I replaced the carb with one from Summit Racing and did a complete tune up. This year I replaced the timing chain, water pump, fuel filter and the ballast resistor. I didn’t replace the fuel pump because at the end of last year it seemed to be pumping plenty on gas to the carb.
I could really use some input and would appreciate any help.
Thank You.

 

Your engine controller (the brain box) may be getting hot and failing. These used to be fairly easy to find at parts stores. It's just a plug and a couple of bolts. If you're still running the lean burn, I'd convert to regular electronic ignition.

 

No engine controller on a 78 and it should have electronic ignition. Seems you covered everything, Is the fuel good? Are the terminals showing any signs of heat on the ballast? These trucks have a lot of issues with the electrical system check the bulkhead connector for ant burn wires/connections.

 

What kind of choke is is running? Sounds to me like the choke is sticking on? I would guess its an electric choke but I have not worked on these enough to really know for sure, could be as simple as a broken or disconnected wire.

 

In 1978, I've seen both regular and lean burn ignition systems. The engine controller on electronic ignition is the brain box. I've replaced several that would fail when they get hot.

 

I got to play with the truck a bit today and there is no so no engine controller. I have an electric choke that seems to be working fine.
I have replaced the ballast resistor, ignition control unit and the voltage regulator. I removed the fuel filter and cranked it over to get some fuel out of her and it looks and smells fine.
I don't know what to make of this, I get in the truck hit the gas twice and it fires right up and every time it stalls it fires right back up.
Tomorrow I going to have really go through the wiring very closely. I'll keep you up to date.
I just want to thank you all for your input and help I do appreciate it.

 

does it smoke black when is stalls? thats a good indication of flooding out, needle/float sticking also comes to mind

 

The ignition controller/engine controller/ brain box are all the same thing. If the brain box is new, make sure it has a clean ground. I worked on a rust buggy once that the fender was so rotten, it wouldn't ground to the chassis. I ran a dedicated ground from the box body to the battery. The box MUST have a good ground.

 

Hello,
Ok so I have to fix a typo, I meant to write I don't have an electric choke, it's a divorced choke. It doesn't blow any smoke at all when she stalls out. I'm going to remove the ignition control unit and make sure I have a good ground and run a dedicated ground to the battery.
Thanks guy.

 

??? you mean mechanical choke.
What carb do you have? Is it a stock replacement 4bbl or what? Some pics of carb and distributor may help.