I have a 1985 Euro Spec 928 that only occasionally gets driven. It has always started in the past, but recently I started having intermittent issues. Initially, the issue seemed to occur when the transmission was in park, if I was in neutral, it would start. Gradually, it stopped consistently starting in park or neutral, now it may take 15 minutes to finally get it to start. When I turn the key, everything powers on, but nothing happens, it doesn't click, crank, etc. Based on the Park/Neutral issue, I think it might be related to a neutral safety switch? Maybe it's the ignition switch and the gear selection is not related? Any ideas how to troubleshoot this, or how I could eliminate some of these options?
Thanks,
Dave

 

With a 12 volt test light, a helper to hold the key in the start position, and a wiring diagram, this is pretty simple to trace.
Which of those do do have, so we know how to help?

 

check the ground bundle behind the RR interior liner

 

Thanks Greg. I have a 12 volt test light, and a helper, I don't have a wiring diagram.

 

Sounds like probable issues are with the selector/indicator switch at the transmission, electrical ground(s), or the ignition switch.

Perhaps, the first place I might start is just by visually inspecting the terminal 50 wire at the ignition switch. It is the small solid yellow wire and it is not uncommon that they break at the pin. I would also check this wire all the way out to the 14-pin engine harness connector.

Problems with the ignition switch itself usually offer clues apart from causing a no-start, but ignition switches do commonly fail.

 

Thanks for the suggestion. I finally got some time to get out to the garage, and the 14 pin engine harness connector and some pins were a little loose. I put the pins back and clipped the connector back together, but no effect on my no start issue. The ignition switch has some type of cap over the back that seems to be holding all the wires firmly in place, there is also a zip tie ensuring the cap remains tight, so I don't think that is the issue.

 

separate the 14 pin connector ,
with the top engine side of the harness,
use the pin thats furthest forward and closest to the fender ( pin 14).
touch it to the hot post,
the starter should crank, if so then the issue is from the car side of the harness back to the key.

usually its a starter relay that goes bad, or a bad ground strap, or dirty grounds in the back RT quarter panel area
NOTE also inspect the wires in the spare tire well