Jredf

I recently bought (seems to be the start for most of us looking for those tips to the quirks on these sweet little rides!) a 1997 Miata. It is in an awkward stage as it appears the previous "young" owners were setting it up for drift. Whit that being said... There are a few oddities and now I think that those are leading to the car being "possessed" electrically.

First, it has been set-up with some "immobilizer" to where to start it, you have to push up and down on the passenger window button. I don't mind that actually.

A few weeks ago the radio started to have a shut-off issue intermittently. Where it would just turn off and then turn back on. It is aftermarket and it was one of the first things I swapped out in Feb when I got the car. If figured maybe something came loose. Everything is tight so no dice.. Mostly when I hit bumps, but not every time I hit bumps.

Then this past week it got worse. Now the radio, plus the water temp sensor were acting weird. The water temp sensor would peg out to the hot side intermittently--sometimes in conjunction with the radio shutting off, but not always.

Then add on that when I turn on the headlights, it will initial shut off the radio and it will then cycle on again.

Add on next that as I was driving home last night, in the dark, the electrical was so bad that it was like everything was dim and then the headlights would dim and then be normal dim and be normal.

AND lastly--it only does it when we are rolling. Sitting with it on and pushing and prodding on the main harness in the garage and it won't replicate. It does seem to get worse the longer we are driving (I have a 45 minute commute back and forth each day and this is my primary gas saving ride).

Soooooo as I rack my brain... I have a few things going through my head:

-something is shorting somewhere
--is it in the wiring harness?
--is it a faulty ground somewhere?
--issues in the steering column?

Any suggestions on where to start and what to go over would be great.

It is in the garage until I can figure this out...

Thanks for any and all suggestions...

sixshooter

Possibly.
Probably.
Also a good probability.
doubtful, but I wouldn't rule it out.


Remove, sand or wire brush both sides of the connectors for the grounds, and tighten them back. One is under the master cylinder, and another is under the throttle body and toward the engine.

I would also check for burned or abrated wires.

Jredf

Thanks Six Shooter... It hit me yesterday to start with the battery and just look over everything from there to the engine to the grounds. Tonight I will start that venture.

Last night I did note that the battery is not secured in the trunk! It is in the designated area, but has nothing strapping it down. That will be one of the first things and then work from there to hit all the grounds. This car has some corrosion that was nicely hidden away until I started replacing things; so corroded grounds are possible.

mytwo

I would make sure the beltto the alternator is tight. If it iis loose you may not be getting a good charge on the battery and it is being drained
I thought mine was fine . I would hook up a lap top and it would not be long till I would start having problems.
Stopped by an alternator shop to see if he could beef the alt .up some. He walked out with a couple of wrenches tightened the belt some more nad said try that .No more problems
I would try and undo what they have done unless you want it , This could save some future problems

Jredf

Thanks for the ideas...

In the end, I just made a ground wire from the negative battery terminal to the car chassis/body. This solved all of the electrical issues in one swoop!

This cured it as obviously there is a shorting or corroded one somewhere that I did not find. There is some rust on this ride in some places, so it was better to start fresh...

Thanks again for all the brain scratching.

J