My son's 1984 245 started up yesterday morning, and while he was letting it warm up it died on him (I didn't think that has even happened since I changed the AMM last year even once) but he called me and said it would not start back up. When I got home I checked to make sure he had gas (college student notorious on running around on fumes) and he has a quarter tank, so I pulled the coil wire from the coil and found no spark while he was cranking. So I get the Bentley book out this morning and checked to make sure I was getting 12V to the coil and I was getting steady +12V even when cranking (should be pulsed as this makes the coil fire, verified it against my 1989). So I pulled the harness to the pickup in the distributor and verified +12 volts on pin A, and intermittently jumpered the other two pins and did not get spark but I could hear clicking up underneath the intake. I have a inline spark checker so I put it inline with spark plug (still installed in head) and hooked it directly to the coil to distributor wire so as to bypass the distributor cap and rotor. Because I had no spark but could hear clicking, I went to an injector and pulled the connector and found just ground on both wires while cranking, but it does pulse ground while cranking. I checked my 1989 and it pulses +12V. So I have no spark and no power to injectors. The Bentley book is good but info format is very different from the factory Mercedes and BMW info I work with, so does anyone have suggestions on a good logic trail to test. I have a Power Probe, test light, different multimeters, and even a SNapOn oscilloscope if I need it I just don't have a bunch of time to waste and need some suggestions on where to go from here.

Follow up - it looks like I need to first look at the no power to injector problem, and see if the main LH 2.2 relay isn't working.

Follow up 2. Found the main relay underneath the glove box. Backprobing the terminals and the relay connected, I have power at 87/1 when the engine is cranking but only getting a pulsing ground and not sending +12V.