Seems to me that a single diode would do the trick.
That is what I was trying to explain, the issue is figuring the load on the IGN1 side which would be going to the voltage regulator, alternator field, and electric choke if equipped. At the key switch it is isolated from other loads (hence the need for the fix in the first place.) Knowing the load will help size the current capacity of the diode.
what part number did you get?
Something like this 5A version should work:
https://www.digikey.com/product-detail/e...54GITR-ND/76530Not sure if you would need a capacitor from IGN1 to ground to buffer any glitches when going from start to run key position? I would think the EFI has a buffered power input built in?
