Hello all, I’ve read and learned a ton from all of you! Thank you! But now I have an issue I can’t solve and haven't been able to find a similar post.
96 e350, 7.5 v8 in a motorhome.
When I bought it, I had to start it by jumping the starter relay behind the grill. First thing I did was replace it and haven’t had a problem since (been a couple months). Ive worked my way through the rest of the issues and now I’ve read all codes and don’t have any, anymore. Yesterday, I was installing a fuel pressure gauge (electronic) and used the memory wire of the radio for constant power for the gauge (for it to also hold settings memory). After I got done, I tried a few times to crank the truck and it would not turn over. If I jumped the starter relay, it would start again, just like when I got it. I wiggled the park selector and then it would then start again using the key. Maybe misaligned park neutral switch, but HERE is my real question. What I notice is, when I move to start position, I lose power to my gauge (ie memory wire on the radio) and my other gauges, I think, but the truck will still turn over and run.
Is this a faulty ignition switch?

 

Depends on the wiring. Most ignition switches cut power in the "crank" position to non essential circuits since the starter requires alot of amperage to engage.

The next question, does your radio retain its memory settings?

If jiggling the shift handle gets it to start then you definitely have something that needs adjusted or replaced. I'm not too familiar with the autos.

 

The radio has not worked, and actually that was my next project after the fuel pressure gauge -replace it. But, from watching the new gauge, which runs off the same memory wire for the radio, I know that my radio would also not hold memory, if it worked.
I want to fix whatever this issue is before I move along to the radio. Something is not quite right that it is killing the memory wire.
Also, for clarification, the new gauge has two power wires, one -only holds memory, the other power wire actually supplies it’s voltage. Both the voltage and the memory wire lose power in the start position.
How is it possible that the starter solenoid is getting a signal to crank, yet the memory wire loses power in start??

 

The starter solenoid should be on a seperate circuit. So you can't use the voltage gauge as a good reference. The start circuit and run circuit are wored separately. Otherwose, your starter would run constantly with the key on.

 

I understand they are separate circuits, but the memory wire should never lose power, in start, in run or even off. I would think, if on start I lose power to that wire, I would probably lose power to every wire, including to the start solenoid signal - yet it will still start.
So, I still have a question, is this indicative of a bad ignition switch, you think?

 

It’s not the ignition switch. Just swapped one in to see and no change. Still loosing power on memory wire on start.

 

Solved. There are two fuses for the radio, one of them controls memory wire. Evidently if that fuse blows, the memory wire will lose power on start position.
Thanks for all the replies, hopefully this will help someone else along.