Good morning new friends. Long time looker, just joined today for some much-needed help.
1986 E350 motorhome 7.5 L 460 engine. No start issue. When key is held on, and the starter is engaged, it will run. The second I let off the ignition, the engine then dies. Exhaust coming from the pipe. Has gas, a new cap and rotor. I am beyond perplexed. I have checked the obvious things. Does anyone have any ideas? I would really appreciate any leads

thanks everyone. I really appreciate it
take good care
Ty

 

Could it have a bad ignition switch or relay?

https://www.google.com/search?q=ford...client=gws-wiz

 

When the engine starts, try turn the key back just a smidge. Seen this before, switch a little sticky so it doesn't fully return to the run position.
Might be the problem, might not.

 

To be sure, get a testlight and clip it to ground and probe the + wire on the coil to see if you always have power to the coil, or you lose it when you let go of the key.

 

thanks a lot Franklin2:

I took the centre wire off the dis. cap and probed it with test light.. Wife turned it over and it did not light. I guess that part sends power to the cap and rotor?
motomaster part # D5AE-12029-AB ( i believe it ends in AB... hard to see)
is this what you were talking about?

 

I think he meant the + wire at the coil but I guess the center wire at the cap will show your not getting spark signal from the coil.

I would guess next is to make sure your coil connector is good. Mine was pretty corroded a few years back. I replaced them with what I had, but here are the correct terminals in the boxes.

 

thanks Max Capacity.

I didnt know there was tabs. I tested the boot. that coil is round. with a boot. test light shows nothing there, but the two small terminals on either side light up when cranking. So, it would seem that is working.
I keep wondering about ignition switch. Maybe a whole new ***'y with key?

 

So if the coil is getting power, but not lighting up the coil outlet spark plug wire, I would think you have a bad coil. I think those tow small wires are the power to the coil, from the battery circuit. I'll try and link Gary's site which will have the schematic's.

Before you buy one, wait till one of the experts chimes in.


https://www.garysgaragemahal.com/

Look on that site under "Documentation"

 

Stay off the large thick wires that go into the top of the dist cap and the coil. They are 20,000 volts + and the testlight is only good for 12v.

If the light stayed lit on the small terminals when she turned the key and cranked it, then you are getting power. I would get another ignition module and try it. If it doesn't fix it, it still will be money well spent, it's nice to carry a spare around.

 

thanks a lot for all your help, Ill take a peek at that site

 

thanks Franklin2, Ill try to source one out. They are in the cab? Under the steering wheel?

 

No that would be the IGN switch I believe on the vans also.

What DaveF was talking about is the ICM that is either on the inner fender well, a silver metal box with 2 plugs out of it.
Or it is bolted to the dist. with wires plugged into it.
I just dont know your E350 with a big block to say just what one you have.

I am sure if you buy one and have it in hand you will see just where it is to replace it.
If it is bloted to the dist. you will need a fancy socket to unbolt it and bolt it back in.
Some have ground done a normal one to fit.
Also use the paste that comes with the ICM.
Dave ----

 

hi everyone. thanks so much for everyone's time, efforts and opinions.
it looked to be the IGN switch along side the steering shaft. seems to work good.
It is amazing how a group of total strangers are willing to help so much! Thanks to all!
Ty