And now, a real puzzler! 351 windsor electrical issue

ford
electrical-wiring
van
e150

#1

Long time listener, first time poster.

I have quite the mystery on my hands.

The rig is a 1977 e150, with a 351 windsor. The motro is rebuilt, the tranny is new, and the body is painted and PERFECT. It’s my weekend warrior.

Here is the issue.

I was driving out to one of my favorite fishing spots in central Oregon, when the van (which in the past has run and driven perfectly) start to stall on the highway. It’s acting like it’s running out of gas (it had a half tank of Texico at the time).

I proceed to step on the accelerator pedal trying to power through this problem, which led to 3 backfires that shook the heavens like a cannon.

I pulled over and was able to limp the van to an auto parts store where I purchased and installed an ignition module, and 2 fuel filters. The van started back up and I was on my way. about an hour later the issue came up again. Loss of power on the highway, and having to pull over and work the starter and the pedal again until the van wanted to run again.

Long story short, I made it to the fishing spot, caught nothing, and made it home despite the rig manifesting the same issue.

I have since replaced the cap, plugs, wires, coil, rotor, and the stator (ignition pickup inside the distributor). I have checked and cleaned all ground connections, and have hit all the electrical connectors with diametric grease, and have completely stumped myself.

The issue remains.

I am pretty sure that it is not a fuel issue as starting fluid does nothing. the engine just turns over and wont fire.

A 12v test light on the negative side of my coil is a solid light when I turn over the rig, no pulsing.

When the engine starts, it runs like a dream. When it starts. It’s sitting in my driveway right now, and summer is a wasting. I need some ideas folks. What am I missing?



Johnson in Portland Oregon


#2

For that model, look for a capicitor / condenser on the outside of the distributor. Disconnect it. If the problem is gone when it’s disconnected, try to get a new one. It’s worked before.


#3

For some reason the pick up inside the distributor isn’t pulsing the coil. Check the pick up side of the wiring to see if the connection is the trouble. Check the pick up itself and make sure it is working correctly.


#4

The next time it dies, remove the coil wire from the center of the distributor, hold it near a metal surface and turn the key on and off a few times. You should get ONE SPARK off the coil wire every time you switch the ignition on and off. No spark?? It’s the ignition module. Also, during these years when Ford was perfecting their electronic ignition, they used four or five different ignition boxes. The connectors were different colors. Make sure you are using the correct one. Check the distributor shaft for side to side slop. The gap between the “star wheel” and the pick-up coil is critical…Is there a voltage dropping resistor or resistance wire in the system?? A COMMON failure point…

Another test, when it dies, remove the coil wire from the distributor as above but this time crank the engine. You should a series of nice blue sparks as the engine turns over…

Long shots…There is a filter sock protecting the fuel pick-up inside the gas tank. 35 years of accumulated debris may be plugging it up. When the engine stalls, enough of it moves off the sock to allow fuel to flow again until the process repeats…Also, the rubber fuel hoses, after 35 years, can split and get leaky, allowing air into the fuel lines and crippling the fuel pump…Check the tank connections. Do a fuel pump volume test, see how quickly it can fill a one quart jar…


#5

Thanks for all the advice good people.
Update! Have been following your ideas and instructions. Still sure it is a electrical issue (ahem dielectric grease was used not spellcheck version). Gas and or starter fluid have no effect, and the gas in the tank is clean. Rubber fuel lines are all replaced and good. Distributor pickup is new, ignition module is identical to the original (and it runs well with the new one, when it runs) coil is new, just replaced the starter relay, have been following wires and can’t seem to come up with anything. No slop in the distributor, spacing between the “star wheel” and the pick-up (stator?) looks good and the pickup is new.
No spark from the coil when the key is in on position or sparks when its turned over. The rig will not start. Resistance wire? not sure about where to find this if there is one.

Any more advice?

I will surely let you all know what it was when we get it running again.

Johnson


#6

Does your ignition module have two connectors? See if you can dig up a wiring diagram that shows the connectors and how the module is wired. If a voltage dropping resistance wire was used, it should be identified.

“No spark from the coil when the key is in on position or sparks when its turned over.”

In 1977, wires could ONLY have one of three purposes. They were ground wires, common to the negative battery post. They were “hot” wires, connected to the positive post by some switching arrangement. Or they are signal wires, connecting the pick-up coil in the distributor to the ignition box, the two wires in the second connector…

So in the larger 3 or 4 wire connector, there will be a ground wire, a hot wire switched by the ignition key, and a second “hot” wire which is the “run” wire and may be fed by a voltage dropping resistance wire built into the harness… The fact that you have no spark means the problem lies in this area…


#7

With the test light showing a steady light and no pulses at the minus side of the coil while cranking the engine it means the pick up isn’t working, even though it is new. You need to determine what is causing the pick up to not function. If it requires seperate power getting to it then check that out. Is it getting a good ground to it? Is the wire between it and the coil ok? These are things you need to find out for sure doing the proper testing.