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Ground Cables Connection Mod

9985 Views 40 Replies 14 Participants Last post by  cincinsight
Hi All.
Welcome to the Ground Connection Mod:
’05’s in the garage now, 11 miles on her and I’m doing the mod’s to bring her up to speed. While doing the ground connections I realized I never posted this one, although I had helped many an insighter with this issue. This is something I would fix whether your having an issue or not. Well, here goes…
Back when I had my ’00 Red 5 spd w/AC Insight I went thru a period where recalibrations were becoming more frequent to the point where I’d have 1 or 2 a day. Didn’t know much about insights back then (I’m finding I know less now) but I knew to go bother the dealer (who knew even less) and get turned away “can’t find anything wrong, no trouble codes”.
I did know that I’d had to replace the 12v battery when it was less than 2 years old and wondered if there was a correlation. My current battery was just over a year old. Just for the hell of it went to KMART and got a battery and replaced mine. Recalibrations went back to 1 every day or two. As I used to be a dealer mechanic (back when they fixed cars) I remembered that ground connection issues could cause some unusual symptoms. A bad ground usually wants to be found, a poor ground may need to be chased to get caught.
Got out my SM and looked up the grounds under the hood. Obviously the car has grounds everywhere, I stayed under the hood where contamination would be more prevalent. There’s a ground connection for the 12v battery and two engine ground cables at the left front of the engine compartment near the air filter housing (see pics). Also, one more for the EPS (electric power steering), under the 12v battery box, didn’t bother with that one.
What I noticed at first was that we have copper cables with aluminum crimped ends bolted to aluminum with a steel bolt (electrolysis). What really got may attention was the paint had never been removed from the contact surfaces (now livid). Although this may be acceptable for a regular vehicle I would not expect this practice to be utilized on a hybrid. As I expected, using all the tricks of the trade, I almost couldn’t get the bolts out. A non-mechanic type wouldn’t have had a chance. The ground cable for the 12v battery was the worst. Sanded and filed all the connections (including the bracket for one of the cables, air filter housing mounts to it). Sprayed all with lubricated contact cleaner (Radio Shack) and put all back together with new bolts (Ace Hardware).
Don’t take this as a fix all, recalibrations can be caused by a number of things. This fixed mine though, they went back to one every month or two, which I could live with. I no longer replace my 12v battery every year or two either. And with the paint there all the electrolysis will occur at the very worst place, the threads (there’s that word again!) of the bolts. Good Luck, Jack
You can see the pics at:
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I hope that you realize that the paint and configuration that Honda used may have been depending on the threaded bolt to make the ground connection, and they did not want metal to metal anywhere else? Unless you use NoOX or some other corrosion inhibiter, that you may have made the long term corrosion problem worse rather than better?
When I did my car grounds, I saturated the connections with an electrical oxidation inhibiter like you use when using aluminum wire in a breaker box.
The stuff I used on my grounds, I have had kicking around since I wired my house 25 years ago, it was called NO-OX for no oxidation. I don't know what the current product is called, but the current passing through a dissimilar metal issue is a problem when using alluminum wiring in an electrical sub panel where the copper lugs and aluminum wire meet. It is a grey paste like the heat transfer compound in the MIMA kit, but has zinc or some other metal filler to act as the least noble component and it therefore saves the aluminum. Any electrical supply place may have it? I only bring this up, because I have had an aluminum panel dissolve when I had a cad plated copper lug bolted to it, and would not want to see us make the ground problem worse. My recomendation would be clean, remove paint, cover with generous coating of the corrosion inhibitor grease, then assemble the ground as Jack indicates.
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I think we will need to watch the connections, and see if over time corrosion begins to be a problem. Lawson's information seems reasonable, and would indicate that a new bolt of the same type would be a good solution, if not for the fact that if it worked so well, why are the straps corroded now?
Dont know. My No-OX with zinc filler should help. I will remove my connections next spring, and see how they are holding up. :wink:
Thanks for the MIMA waivers, you will have a lot of fun, and help your MPG.

I think the real name of the product I have is NOALOX , the label is gone so I was working from a 25 year old memory.
Some food for thought.
Grounding is used for handling current, but also for controlling high frequency noise in power electronics. The two grounds cost Honda more than one ground, and car companies are cheap, so why two. The second ground may have more to do with EMI control than current handling. Unfortunately without some specialized equipment one cannot tell if your single ground has increased EMI.
The AM radio is many times ones best noise detection device, but if you have not tried it before, you will have no basis of comparison, if you hear a buzz that changes when your IMA changes assist or regen,across much of the AM band it could be ground related.
Or it is just a redundant ground in case the other fails?
Just don't know.

Bigger is not always better. The reason the wires fail near the crimp, is that they need to flex somewhere, as the engine shakes a lot when idling. If the wire is too big, it will have trouble flexing, and could fail mechanically rather than corrosion related.
I used some #6 wire for mine, and made them long enough so they had only minimal flexing on the ends, and taped them at the ring terminal end so they would not flex there. As with many things moderation is the best rule, even for ground wires.
A tip when working with black electrical tape is to make the last wrap unstretched, so it will stay in place when heated, and to coat the tape with clear PVC pipe cement, to glue the tape into one mass. I have wrapped broken wooden rake handles with this technique, and the tape last for years with no degredation, unwraping, or stickness.
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Lately I find my self in 5th gear in PIMA at 30-45MPH, which at 30MPH is about 1100RPM, or idle. It is amazing how much torque the electric has compared to the gas at that rpm.
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