I've had a few posts on here before, and had some great help, but unfortunately every time I think I have the problem solved, it confoundedly arises again.


Car: 1990 740 GL non turbo, Regina
Problem: Intermittently wont start
Current Suspect: Radio Suppression Relay Wiring (not the relay itself)

Problem history:

-Intermittently won't start the first time every once in a while, but starts eventually... until one day when it didn't and left me stranded at a mental hospital late at night.
-Car cranks but won't start. Couldn't find spark at the time so tried new distributor cap and rotor, checked plugs, even tried new starter coil. None of that worked.
-BCAA comes, and it starts fine for them.
-Wont start the next time, but eventually get it to start and drive it to the mechanic's where it starts fine for him each time. Guessing what the problem is he puts in a new master relay.
-I doubt this is the problem but the car works for a few months.
-Problems again, and it's determined that there's no gas getting to the injectors (sprayed some gas into the manifold and it starts on that gas, then dies) Try switching the radio suppression relay and the relay next to it (a fan relay?) but does not help
-Fuel pump relay seems to work, as the pump can be heard to run.
-Mechanic is convinced that it's a bad pump and replaces it but I think he checked the fuel pressure incorrectly.
-Car still wont start with new fuel pump, but he shows me that it's working.
-I switch the radio suppression relay with the relay next to it and the car starts! Problem solved?? No.
-Next time car wont start we open up the relay and see that one of them has a broken connection. Eureka! We found the problem! Soldered it and the car started and worked...for a couple weeks.
-Able to start the car eventually with some jiggling of the relay connection and the wires to/from it. Some contact cleaner on the connection (could it have been as simple as that?) keeps the car running for a few months.
-Next time the car wont start, I get my friend to crank the starter as I jump the two thick wires from the RSR, and viola it starts! Problem solved (I think), it was a bad relay or two this whole time. Jumping the wires together before I drive and disconnecting them when I park gets me through to the next day when I head out to buy a new relay.
-With the wires jumpered, the car wont start in the store parking lot.
-I jiggle things, wait a bit, and the car starts to drive me home and write this post.

The only thing I can surmise is that there is a problem with the wiring to/from the RSR or there is a loose connection on the other end of the wires. Does anyone have any ideas where I can go from here? What's the path of the wires to/from the RSP? Think it's just a coincidence that jiggling.patience eventually starts the car?