Problem with random wire near coil pack

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mxfive95
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Problem with random wire near coil pack

Postby mxfive95 » Fri Sep 20, 2013 4:42 pm

Hi, I have a random wire (black with red dots and blue tracer) that is connected to the harness along with the coil pack and cas sensor. My coil packs have 4 pin connectors with 3 wires going into each of them.
The wire in question reads positive but 1 volt less than what's at the battery.
Any help would be great. Even if its a link to a wiring diagram.
Many thanks,
Craig :)
The bumper sticker on my porsche

"My other car is an mx5"

manga_blue
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Re: Problem with random wire near coil pack

Postby manga_blue » Fri Sep 20, 2013 4:50 pm

’95 NA8

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mxfive95
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Re: Problem with random wire near coil pack

Postby mxfive95 » Sat Sep 21, 2013 1:38 am

Thanks Phil, found where the wire goes, its an earth for the rear of the engine.

Now for the real issue I have (was hoping that wire would be it).

I've had the car 5 years now, and it slowly kills batteries and Alternator belts over a period of 10-12 months, but has progresivly been getting worse. On start up the Alt belt whines for about 2 seconds. this progresively lengthens over time. The time is almost double if I've used the head light/heater the previous drive.

there is absolutly no current draw while the car is off. Its only on start up and when the engine is running. Its like something is drawing power from the battery while the engine is running and the Alt has to continuosly top it up...

3 years ago i did an engine swap and all went well. nothing got better or worse.

2 years ago the alternator was swapped for a low km jap unit along a new belt. at the same time battery was changed, seemed to do the trick, but then progresivly came back :/

recently I've changed starter motors but still the same issue.

some things I have tried. Tested the battery while running, alt charging at 14.5v. used a trickle charger to top up when car is sitting. same issues.

As of now, I have a new battery with 370CCA and a new Alt belt. belt is adjusted fairly firm. on start up, the belt whines(squels like a pig) for 3 seconds, then for approx 10-15 seconds you can hear the alt working harder than it should, then it calms down (through out this process there is 14.5v at battery). if I then rev the car, the alt instantly has to start working hard again.

Correct me if I'm wrong, But I was under the assumption that the battery only starts the car and the alt charges the battery and powers every thing.

I can only think of these things as the problem A) The operator :oops: B) problem assosiated with the alternator wiring. C) A bad earth somewhere. D) NFI

Is there anything else I could be over looking? Coil packs? Water pump pulley? Pulleys assosiated with the Alternator are too smooth?

I Could easily go to an auto elec, but i like doing things Myself so I can learn. I'm sure its an easy fix too, but just stumped.

The Reward for info leading to the capture of this criminal, A slab of beer :)
The bumper sticker on my porsche

"My other car is an mx5"

manga_blue
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Location: Moruya, NSW

Re: Problem with random wire near coil pack

Postby manga_blue » Sat Sep 21, 2013 10:22 am

Craig, you have some sort of battery/earth/alternator/regulator thing going. It might pay to start a new thread under a title that says you have an alternator/charging issue.

In the meantime I'd start by cleaning the battery posts and clamps and making sure the clamps are nice and tight then taking it to a good battery shop and get them to put a tester on it to check battery condition and alternator charge and current.

I notice you've changed the alternator. You do know that NA an NB alternators are not interchangeable, do you? One has a built in regulator, the other is dríven by the ECU. (I think it's the NB one which is regulated by the ECU but not 100% sure).

Also https://www.google.com.au/#q=alternator ... :miata.net
’95 NA8


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