ignition trouble need help!

[rick conrath]

OK...The problem child is a '78 930. Just recently the car would cut off after a few minutes of running. I know/am pretty sure its an electrical problem, but what would cause this?
After it died I took voltage readings on the six pin CD box connector. I found that pin TD=5.7v and pin 15=0.1v
Let the car sit for awhile and the voltage on pin 15 jumps back up to 11.9/12v...and she starts right up. Let it run..she dies..voltage readings on pin 15 of 0.1v again. I have replaced the two fuel pump relays,the cd box, the coil. Is there a thermal switch which controls the voltage to the cd box at pin 15? Any help would be greatly appreciated.

Rick '78 930

[john walker's workshop]

on the rear electrical board, there's a delayed action ignition cutoff relay. it's what keeps the car running for a few seconds, after you shut off the key. you've noticed that, right? they go bad a lot, and the 6 pin unit looses power to the 15 terminal. you can bypass it by bridging the outer red wires in it's plug with a home-made jumper with flat spade terminals. it's the small silver relay with a tab on top that screws to the board. it has 4 terminals and a little tube sticking out of the bottom.

[rick conrath]

Actually I had not noticed that. I wll look and see if I can identify the relay. There are alot of what appear to be relays of different sizes bolted to the rear electrial board. This would make sense.....
I wil let you know if this works.

Thanks,
Rick '78 930

[rick conrath]

Will bypassing the relay have any negative effects on the rest of the electrical system?

Rick '78 930

[john walker's workshop]

no.