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Battery ground unstable

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Old 10-30-2017, 05:27 PM
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Default Battery ground unstable

I'm having a weird grounding issue. My CAS signal becomes unreadable very easily (could be a RusEFI thing, I know aftermarket ECUs are less tolerant of bad CAS signals).
After adding ground cables between the TB and the chassis, from the harness to the chassis, I came across a solution: mess with the battery ground cable.
I've got an autozone battery terminal, which clamps the cable, and then clamps around the battery.
If I remove the battery side clamp, redo everything, then the car starts up fine - but eventually the car will backfire once or twice, and then it all comes to a backfiring halt.
I'm tired of using the autozone clamps, the Miata's ground cable seems to be on the small side for the clamp anyways. Anyone find anything better?
I also have not yet tried just wire brushing the clamping area yet. I sprayed some old battery terminal protectant on the terminals a while ago, that could be messing with things as well.
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Old 10-30-2017, 06:32 PM
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Buy one of those terminal brushes. Wire brush the battery and the terminal until you see clean, unoxidized metal. Coat liberally with Vaseline. Assemble, and tighten down to very snug, but not so tight you are distorting the clamp. Smear Vaseline over the whole clamp to prevent any further oxidation.

This assumes cable and clamp are in good shape to begin with. If not, discard and replace. Don't fiddle fart around with half assed generic solutions. Get OEM.
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Old 10-30-2017, 07:05 PM
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Originally Posted by rleete
Buy one of those terminal brushes. Wire brush the battery and the terminal until you see clean, unoxidized metal. Coat liberally with Vaseline. Assemble, and tighten down to very snug, but not so tight you are distorting the clamp. Smear Vaseline over the whole clamp to prevent any further oxidation.

This assumes cable and clamp are in good shape to begin with. If not, discard and replace. Don't fiddle fart around with half assed generic solutions. Get OEM.
I’m unsure of how using an oem terminal would assist. Other than the fact that it is crimped onto the connector vs clamped down.

Cleaning the terminal and everything else was my next step. I was more looking for recommendations for aftermarket battery terminals that were more solid than the autozone type.
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Old 10-30-2017, 07:10 PM
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You can buy good cables at autozone or Oreilly that are all crimped up. You won't find one exactly like OEM as it has the battery end, a ring terminal on the end, and a ring terminal in the middle. But you can find cables with crimped ends that aren't junk.
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Old 10-31-2017, 01:25 AM
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Originally Posted by patsmx5
You can buy good cables at autozone or Oreilly that are all crimped up. You won't find one exactly like OEM as it has the battery end, a ring terminal on the end, and a ring terminal in the middle. But you can find cables with crimped ends that aren't junk.
Hmm, would it be a matter of cutting my cable, and then soldering the two together?

Also, I remember one member on here had a very elaborate grounding system in his car involving an extra ground cable specifically to the engine at the alternator.
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Old 10-31-2017, 06:42 AM
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Clean the other end of that ground cable where it hooks to the ppf right in front of the diff. It is often overlooked.

Last edited by sixshooter; 10-31-2017 at 06:57 AM.
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Old 10-31-2017, 09:58 AM
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Originally Posted by sixshooter
Clean the other end of that ground cable where it hooks to the ppf right in front of the diff. It is often overlooked.
I did overlook that, and I'm pretty sure the last time I saw it, it wasn't too pretty.
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