After putting my fuel injection back together, I went to start the engine up. Nothing. I couldn't hear the fuel pump running when moving the AFM air flap, so I figured it must be the fuel pump circuit at fault.
I connected 12V to the pump and it works fine. Disconnected the engine harness at the double relay and gave 12V to the pump wire. No problem. So it must be the relay (I thought these things never fail). I bench tested the double relay and found that the fuel pump side wasn't working. I cracked the case open and this is what I found:
Click to view attachment
Click to view attachment
The switch contact has broken off. I can't that I've ever seen that happen to a relay (although I also can't say I've looked at too many relays). I guess 30+ years of use fatigued the thin metal.
Looking at the electrical schematic and inspecting the inside of the double relay, it appears that this unit is nothing more than two standard relays plus a couple diodes. Being a CSOB, I'm thinking of wiring it up as such using some of the spare Bosch relays in my box o'parts rather than shelling out $90 for a stupid pair of relays. Has anyone done this before?