Mike, I really appreciate you sharing your car expertise through this posting. Your troubleshooting was very helpful and easy to follow.
My '93 cranked but won't turn overt. I tried to eliminate various listed possible culprit but couldn't.
To make long story short (went through a lot of major surgeries ) my mechanic called and told me that the car was finally running.
"Did you have to replace the master relay," I asked.
"No, it just started out of no reason," he said.
"I was hoping it was the MR that was bad."
Although I was so excited to have the car back, for it had been in the shop since mid-May, my mind was not at ease for not knowing the causes this random starting problem. My mechanic handed me the replacement MR and told to hold on to it for a few few days, just in case I need it. So, I left the shop and left the cover underneath the steering wheel in the trunk.
For many days the car fire right up perfectly, so I put the cover back on since there was no need to replace the MR any more. After that, on that same day, I drove to the park. A few hour later, I tried and tried, but the won't turn over. After many stops and starts, I decided to take off that cover...maybe, I thought, it might help.
Sure enough, she fired right up. Oh that was such a sweet sound to my ears.
So what happened? I was still puzzle at the problem.
When I brought the car from the shop, I noticed the sound that indicates the key is still in the ignition, although the key was removed, and the car couldn't be locked without the key. The door-lock problem comes and goes. The ignition switch is now a suspect. After poking around the area around the ignition switch, I stumbled on a loose connection that goes into the switch, on the left side just below the place where the key goes into the ignition
. When I have time, I'll take a closer look at it.