"I pull on the wiring for the radio relay, try the key and the car restarts. It sure looks like it could be wiring to the noise suppression relay. I thought wiring loom engine bay issues were limited to late '80s cars, not a 1990 like this one. Any suggestions? "

This is a common issue, really, and nothing at all to do with the failing insulation of the early 80's. What happens, is invisible oxidation, corrosion, occurs in the connectors at the relay socket, causing contact resistance to increase. With that increased resistance comes increased localized heat. It is a tail-chasing process which is not fixed by replacing the relay; the connectors (socket) must also be fixed.

Terminals are available to repair this wiring issue, and the problem matches exactly the symptoms you report (now). FYI, the way the relay suppresses radio interference is by locating the injection system power source and wiring away from the radio and its wiring, putting this critical wiring out in the rain instead of under the dash. One of the list of 7/9 Achilles heels.


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Art Benstein near Baltimore

If you send me $20 I'll send you a how-to explaining how to make $20 from people on the internet.