Is Radio Wired to Ignition My Problem?

[ApacheOEM]

You Guys have helped me out before - thanks deeply for being here; my appreciation to you and to our host as well!

My mechanic, I trust and I like him a lot; my car audio guy the same. Both are great professionals in my opinion. They apparently disagree somewhat though. Any thoughts on having an '85 911 radio wired directly to the ignition are greatly appreciated!

The problem is that I can take my car for a long ride, but when I try to start it back (10 seconds or 20 minutes) later. It will most often not start - gauges light up, I hear it click, but no starter or turnover. At that point, if I push start it, or jump start it from another vehicle, it always starts (although it may take me turning the ignition key a couple of times on a jump start for it to kick over). I started the car after 2 months this AM and it started right up (the analog clock was still spot on too). I drove it for a bit, took it to the car audio guy, we disconnected everything radio, and it still would not start until it was jumped. The fuse for the radio is removed right now and everything else is completely disconnected, except for the wire that is apparently on the ignition.

My 1985 911 has a relatively new stereo, amp, and powered-subwoofer (radio's left off often to listen to the real music though). The radio head is wired to the ignition with a "trickle" charge to the battery.

I have a (second) brand new battery that holds at a measure of 12.33 volts when left standing. Other than this, the car runs like a dream - no other problems.

My mechanic is telling me that the radio being wired to the ignition could lead to a back feed, melt solder points on the ignition, make it act unpredictably, and ultimately damage the ECU.

I have an appointment now to get it rewired to an available relay/port. I have to be able to trust my car to start. My car loses "cool points" when I have to keep calling on my friends for a jump and I am always afraid to turn the car off.

Rick

[BoxsterGT]

Has this issue of "not starting" happened only since the stereo was installed?

Sounds like there must be a heavy load on the electricals while driving that is related to the stereo install.

The battery & charging system itself must be good for it to start after two months without a jump.

Len

[ApacheOEM]

I think I got too wordy - Point is that my mechanic is telling me that the radio being wired to the ignition could lead to a back feed, melt solder points on the ignition, make it act unpredictably, and ultimately damage the ECU. Has anyone ever experienced this? The radio and all gear is completely disconnected and it is still needing to be jumped to run (seemingly after it gets warm).

[IMR-Merlin]

Sounds like a bad starter if it only happens when hot. Check the batter connections, the connections at the starter and all grounds.

[IMR-Merlin]

I ran a stereo shop for a few years before I got into working in racing. Chances are very rare (almost impossible) that you would have a stereo damage your ECU.

[ApacheOEM]

Thanks so much to both of you for your comments. I think that's what I needed to hear. - Rick

[BoxsterGT]

+1 on starter.