Need help, truck died while driving 96 3500 7.4

[Schurkey]

The Vortec distributor is a known problem.

Does the distributor rotor TURN when you crank the engine? "Spark" is dependent on the crank sensor. The distributor gear can be worn to nubs, the coil will still fire. But the spark may not go to the correct cylinder--which makes the engine stall and not re-start.

I still say this could be a fuel issue--faulty injector harness or some-such. But if you decide to pull the distributor, you might find excess wear on the gear at the bottom.

 

[Jeeperguy]

The Vortec distributor is a known problem.

Does the distributor rotor TURN when you crank the engine? "Spark" is dependent on the crank sensor. The distributor gear can be worn to nubs, the coil will still fire. But the spark may not go to the correct cylinder--which makes the engine stall and not re-start.

I still say this could be a fuel issue--faulty injector harness or some-such. But if you decide to pull the distributor, you might find excess wear on the gear at the bottom.

Will check tomorrow after work, haven't pulled dizzy cap yet, wanted to check other options. Could be injector issue, but there damn near new, replaced them with bosch upgrades not long ago.

 

[Nad_Yvalhosert]

I'll try it, but don't think that is the issue either, Has very good spark on all plug wires. I'm thinking it's something with distributor. Remember seeing something about these models having a distributor issue.

Nonsensical. If it has "very good spark" on all plug wires, then "very good spark" is getting THROUGH the distributor.
If you have "very good spark", but it's not firing the compressed air and fuel in the cylinders, then the spark plugs are stopping the "very good spark".

 

[Schurkey]

I don't see the plugs getting fouled enough to stall the engine while driving home. Possible, not likely.

OTOH, I can see the distributor gear wearing so severely that the rotor is no longer in time with the crankshaft--sparks going to the plug wires, but 1-2-3 (or more) gear teeth out-of-time. Engine stalls while driving, won't restart.

Given low cranking speed, therefore low oil pump drag--maybe the distributor is turning, but still out of time. He'd have spark to the plugs, but still out-of-time so the engine doesn't run.

Even if I'm correct--and that's not guaranteed--by now the injectors have flooded the cylinders. Therefore, the plugs likely need to be cleaned, AND the distributor/cam gears checked for wear.

 

[Nad_Yvalhosert]

It's almost like I recommended checking that 9 posts ago...

Checked for fouled plugs? If its puffing, it's trying to start. If you've been cranking, they're likely soaked with gasoline. Wet plugs dont fire, change your plugs

Hmmm...

 

[Jeeperguy]

I don't see the plugs getting fouled enough to stall the engine while driving home. Possible, not likely.

OTOH, I can see the distributor gear wearing so severely that the rotor is no longer in time with the crankshaft--sparks going to the plug wires, but 1-2-3 (or more) gear teeth out-of-time. Engine stalls while driving, won't restart.

Given low cranking speed, therefore low oil pump drag--maybe the distributor is turning, but still out of time. He'd have spark to the plugs, but still out-of-time so the engine doesn't run.

Even if I'm correct--and that's not guaranteed--by now the injectors have flooded the cylinders. Therefore, the plugs likely need to be cleaned, AND the distributor/cam gears checked for wear.

That's kinda what I was leaning too, for it to just die while driving wouldn't be plugs. It has spark, and fuel, should fire, even with fouled plugs. But had to work late so I won't look at it till tomorrow. Gonna pull cap and plugs tomorrow, Thanks

 

[Jeeperguy]

It's almost like I recommended checking that 9 posts ago...

Hmmm...

Yeah, I get it, but the plugs fouling out enough to make it die and not run while driving?? Never heard or seen if that.

 

[Nad_Yvalhosert]

Yeah, I get it, but the plugs fouling out enough to make it die and not run while driving?? Never heard or seen if that.

Nope, but cranking it, fouling them wet will keep it from starting. Assuming there's no additional problems... Checking off possible problems with definite solutions will help troubleshooting, going forward.
I'm still on possible low fuel pressure. Change the plugs and try starting on ether. If it does have "very good spark", new plugs, and correct timing, it'll fire. If not, you've checked off 4 potential common problems. On to lesser known issues.

 

[Jeeperguy]

Nope, but cranking it, fouling them wet will keep it from starting. Assuming there's no additional problems... Checking off possible problems with definite solutions will help troubleshooting, going forward.
I'm still on possible low fuel pressure. Change the plugs and try starting on ether. If it does have "very good spark", new plugs, and correct timing, it'll fire. If not, you've checked off 4 potential common problems. On to lesser known

Nope, but cranking it, fouling them wet will keep it from starting. Assuming there's no additional problems... Checking off possible problems with definite solutions will help troubleshooting, going forward.
I'm still on possible low fuel pressure. Change the plugs and try starting on ether. If it does have "very good spark", new plugs, and correct timing, it'll fire. If not, you've checked off 4 potential common problems. On to lesser known issues.

 

[Jeeperguy]

Ok, so it ended up being the rotor, the cheap ass oriellys rotor broke around were the screws hold it down. Was less than 6 months old,, Had a new one already in the garage, fired right up, fouled plugs and all.