No start signal to Motronic

#1

To make a long story short, I took a bare coupe body and installed a complete chassis and engine harness from a vert. Got everything connected. The vert was an automatic so I had to jump the gear shift selector pins to get the starter to spin. Problem I’m having now is that the main relay is not pulling in. It has power to it but the Motronic is not providing a ground for the relay to energize. I believe this is stemming from the fact that I don’t have a start signal at pin 27 of the Motronic. The Schematic shows a solid conductor without splices or anything going from the ign switch to the pin 27. No wire colors though.

To throw a monkey wrench into the mix, the previous owner of the car from which the harnesses are from had a switch on the consol that had to be turned on to start the car. When Ipulled the wiring out of the vert and into this car, all that bs fell off.

I need to trace the source and the wire from which this start signal comes from

Ray

#2

Just took the plug apart to the Motronic. It’s a small gauge gun wire. I feel like Sherlock Holmes

Ray

#3

Apparently that black module under the dash with the two green connectors is necessary to establish 12v at pin 27. After that, there was a loose connection and a fonzy type whack to the fuel pumps that got it running. Woohoo

Ray

#4

I think that box you are talking about is for the OBC code function. If you unplug that box and jumper the two big green wires you bypass the relay in the box that is looking for a code. I had a long term stalling problem traced to low voltage on that circuit and it was as loose shorted connection at that box.

#5

My thought exactly. Now that the car is running, I planned on eliminating a lot of wires and modules throughout the car.