jnor10

Wanted to share with the forum my experience with a recent electrical issue I was dealing with. Basically, I was dealing with a bad ground. The symptoms were loss of HID headlights at low RPM's, my Valentine-1 would lose power and the radio would cut out. Even opening the door with an idle RPM would set all the above in motion. I replaced the ground strap to the starter-transmission over the summer, thought that solved it, but it didn't. I most recently replaced the battery ground strap, which appeared in perfect condition and for a month now, no problems!

I'll have to keep in the practice of heal and toe down shifting and left foot braking; all techniques I employed to keep the rev's up while slowing. Just glad I don't have to do it all the time now.

Anyhow, hope this helps someone if they are scratching their head with a similar problem.

AOW162435

Jeff,
Congrats on finding the culprit. It seems like bad ground straps have been an issue for quite a few people here. What was the approximate cost of the strap?

Andreas

jnor10

It's was about $10.00 from Sunset.
Amazing how such a low dollar, simple part can solve a major issue. I checked the connection for integrity, the strap appeared faultless.

Anyhow, its a cheap, easy approach to rule out electrical issues.

nikdog

is it possible the strap wasn't bad just the contact points needed to be "freshened" up

jnor10

Yeah, I thought about that too. I did clean up the contact point on the car's body. But, I only did it as an additional measure, not because it appeared to be in need of it. But, for the price of a strap, it just made sense to replace.

Chuck W.

Same problem 2 months ago, a bad battery ground strap. My car would start, then after being driven a short distance it would die. It also effected the immobilizer. At times it would work and at other times it won't.

tj90

My cars immobilizer intermittently worked and lights started to flicker. I checked this thread and found that the battery strap may be the culprit. Check out the 2 attached images. The first image shows the resistance between the negative terminal and the copper strap. It shows 115 Ohms of resistance (should be zero) - sometimes I was getting 3700 Ohms. Anyway, by putting force on the cable with my finger lowere resistance to 5 Ohms. I suspect the problem is between the copper cable and terminal block. 5 ohms is an improvement, but again I would expect 0, I will take off cable and let you guys know what I find.

jnor10

let us know how it goes. hopefully its an easy solution, as mine was.

Jeff

tj90

I took the cable out, sanded down all mating surfaces at the car end and battery terminals. I then pounded the terminal end into the copper strand with a persuasion hammer and anvil. I put a thin coat of ox-guard on all mating surfaces (battery and car end), reassembled and viola! Resulting resistance between battery post and bolt into car was 3 Ohms... No more flickering lights and the voltage was stable - either 13.6, 13.4 or 13V depending what accesories were on - using my Escort X50 readout while driving around. (man thats handy feature - ive used it 2x on this car diagnsing a problem - bad VR a year ago and now this). Before the fix, the voltage was very quickly bouncing btw 11.? and 13.? V too quick for me to read it....

Again, thanks to Jeff and the R-list for saving me a weekend to quickly diagnose this problem...

Come to think of it - my radio was cutting out when I would hit a bump for a month now - could have been the cable this whole time when I thought I needed a new radio Not sure why Im still seeing 3 Ohms resistance while in circuit - when it was out on the anvil I was seeing 0.2 Ohms. I think its the current draw from the battery increasing the resistance See the readout is negative in the images - the DMM is being fooled by leakage current.

jnor10

Glad it worked out for you. I think that the problem area may be the contact of the battery ground to the body. Mine was clean in appearance, but evidently a film develops over time. I think replacing my ground strap may have been overkill, likely the cleaning of the contact point that was responsible for the success.

My radio was cutting out all the time as well. Maybe a good telltale of this problem.

good job!

Jeff

Davies

That was my canary in the coalmine a few months back also. Replacing the battery's negative ground strap solved a whole host of electrical weirdness (radio and headlights cutting out, spontaneous dash warning lights, weird RPM sensitive buzzing noise in the speakers...I'm sure I've missed some...).
The strap looked fine (no rust or acid buildup) and was tight and secure, but a new one worked like magic.

I would even go as far as recommending replacing the strap as an inexpensive pre-emptive measure to those who haven't already.

jnor10

I agree, I'm just wondering if its more the contact point than the cable that is solving this. As mentioned in my original post, my cable "appeared" perfect. Would a good cable have a specific resistance that is measurable?

Davies

Before I threw the old cable out, I inspected it and it the metal strands in the braiding appeared dull. Pure speculation on my part, but seeing as the cable is uninsulated, I was wondering if a decade of conductivity could attract a layer of ozone (or whatever the hell it's called) to the strands in the metal braiding that would actually create a defacto layer of insulation around each of the strands, thereby cutting off conductivity.
I didn't think about it too hard however, as a new cable cost $15 and took about six minutes to install.

Jukelemon

ANY copper strand will have resistance-no matter how small. That is why you don't run 200ft electrical cords for power tools ( : Resistance in the copper creates heat i.e. it is like an actual resistor. Likewise on audio applications.

Anyway, I would venture to guess that the strap AND the grounding point has issues. Unless the strap has be soldered at the ring terminals, it is NOT an ideal grounding strap. Simple fix there. In terms of the grounding point, you need to make sure there is NO paint or corrosive residue on the body point i.e. ground down with wire wheel and then apply a conductive type paint/surface prep. Cover with a common, non corrosive weather proof solvent. Fixed I would think.

In terms of why the resistance increase, copper changes form without insulation i.e. oxidizes and looses its conductivity specs. That one cable looks very very good which makes me think it is a terminal/strap issue and body point.

Get a soldering iron (hi wattage) and run some solder through it then put it back on. Post back.

tj90

The problem in my case was the strap where it connects the battery. You can see in the pics that the DMM was between the part that connects the battery post and the copper. A few strikes to the metal that connects the copper strap was all that was needed to break any surface oxide layer and re-establish a good connection. With the strap out of the car after being hammered, the resistance between the strap where it connects to the car and battery terminal end is less than 0.2 Ohms, no matter how you mechanically stress the interface where the cable meets the battery terminal end. It looks like its a crimp connection that is not sealed. I guess I could have soldered and sealed the area, but the original crimping in that area lasted 12 years, so Im hoping the persuasion hammer was good enough for at least another decade. If anyone trys soldering, you will need a torch. No solder iron will be able to inject enough heat into this strap without it wicking away with that copper heat sink.

When I originally removed the cable, the resistance was swingly wildly as you moved the copper strap in the battery terminal end...