My 84 B350 starts and runs fine until it gets hot, then dies. Won't restart until it cools. I've changed plugs, wires, cap, rotor, ignition coil, ignition module, ballast resistor, voltage regulator and carb. Fuel pressure is good and vacuum reads 20 from the manifold. This is my work truck and I can't get working if I can't get it moving. Any help or ideas is greatly appreciated.

 

Sounds like your EGR valve is opening up too far. There is a vacuum line that runs from the EGR valve to a coolant sensor. That coolant sensor remains closed until the engine heats up, then it opens and starts applying vacuum to the EGR valve. I suspect that once the engine has cooled enough for this coolant sensor to close and cut off the vacuum supply to the EGR valve, you are then able to start the engine. The next time it stalls, disconnect and plug the vacuum hose going to the EGR valve and see if you can then start the engine. If you can, replace the EGR valve and gasket.

 

The studs coming from the manifold that the egr bolts to are rusted pretty badly. They're not threaded enough anymore to put on a nut once the egr's in place, so I blocked off the hole where it was with a piece of sheet metal and gasket. It doesn't seem to be leaking, but I'm not 100% sure. I also blocked off the vacuum line going to the egr valve. Could this be my problem, and if so, what should I do? Thanks.

 

Maybe it's not leaking to the outside, but it could be leaking between the two passageways underneath your sheet metal plate. This would give the same effect as if the EGR valve were open all the time. I would pull the plate and inspect for signs of any leaking going on.

BTW, did you have this stalling issue before you removed the EGR valve.

 

My '89 does not have studs holding the EGR down, but 10 mm bolts.

Perhaps soak the studs with some penetrant for a couple weeks, remove and replace them.

Also, on my '89, the vacuum to the EGR is controlled by a solenoid attached to the pass side valve cover, but this is not relevant.

When my EGR was stuck open it was stalling when hot.

I agree with Alloro that the plate you replaced the egr with can be allowing the gasses from one port to the other. The bases of the EGR valves are pretty beefy

 

It stalled once, then I blocked the EGR valve. It ran for a couple of days, but pretty rough. Then it would only start then die. When it does run before the engine heats up, it seems to run strong, then it almost seems like it's not getting gas and just dies, but the carb is still spraying gas.

 

Yeah, that does sound like an EGR issue to me.

 

Thanks for all the help. I'm going to check it out tomorrow. I really appreciate it.

 

did you ever figure this out?

I'm in a touring band. look at my user name, thats what we have as far as van in concerned, lol.

anyway, ours does something similar. On the highway, its fine. But slowing into traffic, itll just die sometime. after letting it sit for a while (30-40 min) it starts just fine. rarely we have to use a little starting spray. But it ONLY does this when its really hot out, never in the spring / fall / winter. Totally confused.

I know some car stuff, please help - we have a tour soon!

 

I had bought a bad ignition module.It kept shorting out sometimes. Which didn't make it stay running,I guess.I changed that and works fine.