Need some Miata help

Hello All,

I can no longer start my 1990 Miata with the ignition key -- but I can bump start it. How should I go about diagnosing whether it is the starter that's the problem, or the ignition switch?

Symptoms: when I turn the key I get all the gauges and power. But, there is no clicking or any type of life from the starter. I noticed yesterday that when my son started the car, it sounded like he was dragging the starter motor (I mean, leaving it cranking after the car started), and he never does that.

Then today, at an autox, my co-driver started the car, and reported seeing a brake light, and hearing a weird noise. When she turned off the car, it wouldn't crank. I noticed that when I tried to start the car, the brake light comes on (as per usual). I have hypothesized that the switch is broken, and that when it was last successfully started the started didn't fully disengage (hence the weird sound) and the brake light showed because the key was still turned all the way over (a sticky switch, or broken switch). The switch now doesn't feel the same, but that could be me looking for evidence for my diagnosis.

Thoughts?

Rob

Sounds like the switch to me, but if I were you I'd wait until somebody with more knowledge chimes in before I dig into it on my advice.

Easy enough to check if the solenoid's getting power with a test light or a volt meter. That would let you distinguish between the switch and the starter.

But it does rather sound like the switch.

Keith Tanner wrote: Easy enough to check if the solenoid's getting power with a test light or a volt meter. That would let you distinguish between the switch and the starter. But it does rather sound like the switch.

That will be my learning for tomorrow. I've never used either a test light or a volt meter.

Test lights are easy. Attach one end to a ground, touch the other end to the thing you think might have power. Does the light go on, yes or no? If you can work a computer thingy well enough to post to an internet forum, you can handle a test light

Today I get a click when I turn the key, and there is power to the starter. Does that mean I can rule out the switch?

Yup, if there's power at the solenoid, then it's not the switch. The starter will always have power.

Diagnosed the starter button on a friends modified camaro by just jumping the solenoid to start the car. I forget if it would work on a Miata, but might help you.

edit gonna have to have someone press the clutch pedal...

I just had my '91 Miata's start go flakey. Sometimes it would start, other times no clicks, no nothing. I replaced it and it all is well for now.

I called the local parts store and they had it in my hand the next day. I think Rock auto wasn't any cheaper and I didn't have to ship a starter back to get the core charge.

RossD wrote: I just had my '91 Miata's start go flakey. Sometimes it would start, other times no clicks, no nothing. I replaced it and it all is well for now. I called the local parts store and they had it in my hand the next day. I think Rock auto wasn't any cheaper and I didn't have to ship a starter back to get the core charge.

Luckily I have a replacement starter -- leftovers from the Locost build . . .

It looks like an "underneath the car" job. Is that what you found?

Under the car and through the passenger's wheel well.

In reply to Keith Tanner:

Yup. I had a hell of a time getting the bolts started from under the car and couldn't reach it any other way.

I sinned.

I used an impact driver before I started the bolts. I reached my personal limit. Hopefully it doesn't come back to bite me. If it does, I think I paid less than $60 for the starter with some coupons.

Well that wasn't so bad -- about two hours total time, in 35 degrees C weather, over 40 with the humidex. I guess hot yoga is paying off . . .

As it turns out, it was both starter and switch. I got the new one in, with little frustration, and the car started immediately. But when I started it a while later, the starter stayed "lightly engaged" and I had to fiddle with the key to get it to stop engaging. So, I suspect that my co-driver started the car, the started didn't disengage due to a failing switch, and somehow that "burnt out" the starter (do they really do that?).

New switch should be here tomorrow.

The switch arrived. That was a ten minute job. It is amazing how much dust accumulates inside the dashboard after 23 years!

Everything is A-Ok now . . .

Yay!