2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Possible ECU problem

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Old Feb 7, 2004 | 07:30 PM
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From: Beyond Hope
Possible ECU problem

Hi, guys, it's great to be here.

I got a weird problem with my RX7...

I've just recently replaced the pulsation damper, as my old blew up. Everything came apart fine, went back together fine. Drove it down the road, turned around, came back.

Got my books and started off down the road again.

Got about half a block away, and the car died. Just went phffft.

Got it back to the garage, (pushed it back ,I should say) and started doing some testing. I got no spark on either the leading or the trailing ignition coil.

Pulled off all the leads into the ECU, and got a faint, pitiful spark (singular) when I started it.

Put a voltmeter on the ECU test thing, and I'm getting 3.000 volts off of DCC1 and 2...with a 470 ohm resistor in the circuit. No voltage changes at all. Anybody got any ideas whats wrong?
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Old Feb 7, 2004 | 09:25 PM
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From: n
Battery/alternator is dying?


-Ted
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Old Feb 7, 2004 | 11:38 PM
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From: Beyond Hope
Nope...battery's only a few months old, and the alternator's fresh off the rebuild bench...as is the starter.

Not to mention, we've got a jump starter on the thing.

Oh, also, I'm getting odd voltmeter readings on the coils. Even when the key is not in the ignition, I'm seeing 12 volts across the coils. Is this normal?

2nd odd thing: Turn the key to start the engine, nothing happens...but the shift light turns on, and won't go off until we pull the negative battery cable off the post. :?
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Old Feb 8, 2004 | 11:25 AM
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From: Beyond Hope
bump...anybody got any ideas/words of wisdom?
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Old Feb 8, 2004 | 01:29 PM
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From: Beyond Hope
Umm...silly question...If I pull the ECU off of a '85 1st gen, would it work in my '86 2nd gen?
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Old Feb 8, 2004 | 02:17 PM
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From: Beyond Hope
Okay...well, I was going to edit my last post, but never mind...

Anyways, I built the tester described herein: http://www.teamfc3s.org/info/article...odes/main.html

And plugged it into the ECU test port...and it comes back as nonblinking lights...that don't go off.....ever.
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Old Feb 8, 2004 | 02:19 PM
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From: https://www2.mazda.com/en/100th/
Originally posted by FallenDruid
Umm...silly question...If I pull the ECU off of a '85 1st gen, would it work in my '86 2nd gen?
no they are totally different. 86-88 non turbo is the same though
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Old Feb 8, 2004 | 02:21 PM
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From: Beyond Hope
I discovered this, actually...the 86 has a three port connector and the 85 has two big ports, and bunch of other crap..a well...it was a forlorn hope at best.
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Old Feb 8, 2004 | 02:59 PM
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From: Beyond Hope
Found the problem...

capacitor 941 inside the ECU is a toasty muffin...blew hard enough that it burned the circuit trace right off. Now I just have to fix it.

No user serviceable parts inside...

I say thee Ha! Ha! I say.
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