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Negative Earth Connection - front bulkhead

C

Channel Hopper

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Location
KT8 Postcode
Car
Accord 7 Estate 2005
I had the car die on me for the first time in weeks after short town journeys, I've got a replacement battery coming tomorrow as the one in there was out of the previous car and is somewhat smaller in size.

Stupidly I had parked on an uphill stretch with no turning circle, usually I would ensure there is a short downhill stretch and then coast before putting into second. I'm now suspecting that there is still a leak that means the pump/fengine is slightly starved with the engine uphill of the fuel tank but can't prove it until I fix the electrics and crank speed, so a better battery for starters.

In waiting for the ride home, I tried a few things to get her going, cleaning terminals and lead / copper washers all round, and found that the negative cable path is split where it presumably goes to the engine earth point under the battery holder, with a small section terminated at a 10mm bolt just above the LH headlight.

Under the large spade terminal is the same primer and paintwork adorning the outside, though I know this car had a knock on this side since the headlight is spanking new and glaze free (unlike the RHS that needs cutting and polishing every six months or so) .

Scraping away the paint to bare metal allowed the car to crank a lot faster even with the almost flat battery so the questions are ;
Should this point be paint free where the 10mm bolt is, or was it simply the battery recovering a bit in the interim ?
and
Since the bolt is only a 6mm thread, what is this termination supposed to do if it is potentially important to starting on a cold morning ?


Thanks in advance
 
check earth's if not could be engine fuse box I had to replace mine as vehicle used to.cutting out and then died on me one day

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The front earth connection mentioned is the only one that I worked on, and only because of the paint that I found under the earth tag on the negative battery cable. I might have inadvertently moved something else that is critical but I did not take the cover off the large fuse box.

Since I had nothing better to do after the car wouldn't start I scraped all the paint/primer off and after bolting back down the starter is so much better at cranking. This is on the same, smaller battery by the way (the replacement one is still in the boot).

Even a first morning start in this weather, so I am wondering if this eathing point is a little more important that people realise. It might impact on the solenoid connections, or the charging circuit, or both.

Certainly something to look out for if other members are having trouble as winter draws on.
 
Earth points are a big thing, much more so than people may realise, with DC the electrons are carried along the outside of the conductor and any form of corrosion will lead to high resistance.
Subaru use a lot of earth points on their flat 4 engines to prevent galvanic corrosion damage inside the engine, have a look under a impreza and you'll see earth straps from the heads to the chassis in many places.
If in doubt a good ground and clean connectors make a big difference to all kinds of electrical loads charging etc.
Probably when that strap was new and clean it was ok, now with some years of corrosion on it and the poor grounding through the tips of the retaining bolt it may be sub-optimal and cleaning the ground will help it a lot.
Cover the area with silicone dielectric grease afterwards to prevent corrosion, or Vaseline if you have some to hand.
 
Thanks and yes, I understand the need to protect.

If anyone has five minutes to spare then please advise if their bodywork is painted underneath this earth strap, or bare metal.
 
Checked mine, it is painted, took the opportunity to clean the terminal with a wirebrush and steel wool. Cleaned the mounting area as well, not to bare metal but a but bigger area for the brass terminal to ground to. Cleaned the bolt as well and covered the lot with silicone grease.
 
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