I am trying to rein down a problem with my converted XJC and the number of Suncoast Conversions gets an “unavailable” recording. If anyone has any experience, I have a 91 350 TPI in the car, and am dealing with a startup failure that I suspect is a known issue with the GM Passkey module. The starter circuit checks out but turning the key has no effect. The problem has been intermittent since I bought the car and became more frequent. The fuse to the unit blew once last year. I have no way to diagnose the hardware and I’m thinking about just sending the ECM out to have the passkey programmed out. Anyone else done this?

 

I sent my PCM to Sinister Performance and am very happy with his tune. He can delete your passkey and offers many levels of tune or can perform a complete custom tune. I have no affiliation.
https://www.gmtuners.com/

Dave

 

I had a similar problem before lumping mine, that would occasionally pop up after the swap, turned out to be the jag starter relay! Swapped it out and haven’t had a problem in over 5 years,

 

Darren, I’ve replaced the ignition relay, the neutral safety switch, and the ignition switch. I’m pulling out what hair I still have. Power to the relay and the starter lead both fire up the starter. It and the solenoid were new as of last year. The only clue I have is that when I turn the key to Start, I’m hearing a relay click in either the VATS or the ECM. I think the best guess is to send out the ECM and have it bench tested and a VATS delete.

 

Good idea also is to buy an extra ecm off ebay, they're getting older and electrolytic caps have a shelf life at best. Grab a used one for cheap and have it gone through and reprogrammed, swap it out for your intermittent one and then have it gone through and shelve it for a rainy day.
Maybe even just buy a "engine swap" ecm already programmed on ebay?

 

Excellent suggestion. Sometimes when you’re in the weeds the most obvious solution eludes you.