Ground Strap Issue
10-04-2009, 02:43 AM
#1
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Ground Strap Issue
My car was cutting out intermittently.
Usually, tach would drop to zero, indicating a stalled car, which would then restart immediately.
Would do this at highway speed.
Worse under load or so it seemed.
Sometimes associated with hitting a bump, often not.
I "made up" all kinds of data and cause/effects. Most with a data set of 1 or 2. Thought I'd fixed it a dozen times. Baffled me.
The original flat, plastic coated ground strap failed. It failed intermittently, then terminally (so-to speak).
Today at the FRENZY 13 event, a couple of us disected the failed cable.
Despite a very good outward appearance, we found the failure (Bad localized corrosion) buried under the plastic sheathing near the end that bolts to the car body with the T-handled nut.
Jadz928 took pictures of it and will likely post them.
ALL y'all need to keep this failure in-mind. It might happen to your car. Probably sat for a long time with that area wet occasionally.
Usually, tach would drop to zero, indicating a stalled car, which would then restart immediately.
Would do this at highway speed.
Worse under load or so it seemed.
Sometimes associated with hitting a bump, often not.
I "made up" all kinds of data and cause/effects. Most with a data set of 1 or 2. Thought I'd fixed it a dozen times. Baffled me.
The original flat, plastic coated ground strap failed. It failed intermittently, then terminally (so-to speak).
Today at the FRENZY 13 event, a couple of us disected the failed cable.
Despite a very good outward appearance, we found the failure (Bad localized corrosion) buried under the plastic sheathing near the end that bolts to the car body with the T-handled nut.
Jadz928 took pictures of it and will likely post them.
ALL y'all need to keep this failure in-mind. It might happen to your car. Probably sat for a long time with that area wet occasionally.
10-04-2009, 08:45 AM
#2
Team Owner
If you have a failed cable I would suggest to add some kind of sealant to the cable end Dow Corning 111 comes to mind or Dielectric grease ( mash it into the end near so the stuff fills the voids between the wires)where it goes into the plastic cable cover.
Whats happening is when your car gets wet, water is finding its way into the rear hatch area along the bottom of the tool tray this water then gets the cable wet, and the corrosion starts.
So you could also inspect the rear window seal and the hatch lock cylinder for leaks, if you have a spoiler then remove it and inspect the sealing washers and add new sealant 3M strip caulk works well for this found at the auto body supply
Whats happening is when your car gets wet, water is finding its way into the rear hatch area along the bottom of the tool tray this water then gets the cable wet, and the corrosion starts.
So you could also inspect the rear window seal and the hatch lock cylinder for leaks, if you have a spoiler then remove it and inspect the sealing washers and add new sealant 3M strip caulk works well for this found at the auto body supply
10-04-2009, 09:25 AM
#3
Rennlist Member
Thread Starter
As heavy and pretty as that cable was, I never expected it was a possible failure point, especially after polishing the ends. Little did I know...
The main point I'm trying to make is it looked perfect, but had corroded in a very specific way / place. Hidden.
And that it might be happening to others with intermittent power loss. One minute I had 12.8 volts in the wiring system, next minute, sub 8, , causing all kinds of intermittent hell for me.
Probably occured for exactly the type of reasons you are noting, plus the electrical potentials contributing to the localized acceleration of the effect.
Don't overlook this, folks, its a real simple but hidden situation that can make you do crazy **** like buy new brains and sensors and wiring harnesses, etc.
This has occured sometime during the last 24 years, probably during the 10 years it was parked.
I agree with root causes , its just that the car isn't wet there anymore and doesn't seem to leak at all.
The main point I'm trying to make is it looked perfect, but had corroded in a very specific way / place. Hidden.
And that it might be happening to others with intermittent power loss. One minute I had 12.8 volts in the wiring system, next minute, sub 8, , causing all kinds of intermittent hell for me.
Probably occured for exactly the type of reasons you are noting, plus the electrical potentials contributing to the localized acceleration of the effect.
Don't overlook this, folks, its a real simple but hidden situation that can make you do crazy **** like buy new brains and sensors and wiring harnesses, etc.
This has occured sometime during the last 24 years, probably during the 10 years it was parked.
I agree with root causes , its just that the car isn't wet there anymore and doesn't seem to leak at all.
10-04-2009, 09:35 AM
#4
Team Owner
next time you wash the car make sure to towel dry the hatch crevices pay attention to the floor area , if there is water in there that you have a leak.
Glad you got the elex system figured out though.
Glad you got the elex system figured out though.
10-04-2009, 11:10 AM
#5
Three Wheelin'
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Great tip! We hardly get rain here and have consistent low humidity (15-20%) in the desert but I wash California (my current DD) more than any of the other sharks (about twice a month, it seems). I do have inconsistent readings on the volts gauge (sometimes high, sometimes low, most of the time right in the middle). I also get consistent voltage readings at the front charge post of 13.5 volts regardless of what the gauge is showing (which leads me to believe the problem is in the front engine harness or the pod). However, your post has me curious so I'm going to check the cable for corrosion and check for moisture after the next wash just as a preventative measure. THANKS for posting!
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10-04-2009, 01:36 PM
#9
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Thread Starter
I'll try to fix it, assuming it is long enough.
I thought one of those Frenzy 13 guys was going to mug me for the good copper left in the strap.
So, here's some additional confounding information. And solution ( I think ).
Car was also missing. It would miss after a hard throttle run, not during the hard throttle, but after returning to light throttle cruising after an acceleration.
This behavior was mixed-in with the occasional cutting-out. Happened a dozen times to and from the Frenzy.
The cutting-out was gone when I changed the ground strap, but occasional missing stayed. This morning I disconnected the O2 sensor. No more missing.
So I had at least two problems last week, bad ground strap and bad O2 sensor.
I thought one of those Frenzy 13 guys was going to mug me for the good copper left in the strap.
So, here's some additional confounding information. And solution ( I think ).
Car was also missing. It would miss after a hard throttle run, not during the hard throttle, but after returning to light throttle cruising after an acceleration.
This behavior was mixed-in with the occasional cutting-out. Happened a dozen times to and from the Frenzy.
The cutting-out was gone when I changed the ground strap, but occasional missing stayed. This morning I disconnected the O2 sensor. No more missing.
So I had at least two problems last week, bad ground strap and bad O2 sensor.
10-04-2009, 01:38 PM
#10
Team Owner
clearly this connection has gotten wet. A simple fix would be to hit the connection with a hammer, but the best way would be to clean the connection with some torch heat and flux then put some solder on it then some DC111 or dielectric grease, OR just put a new cable in
10-05-2009, 12:52 AM
#13
Supercharged
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Continuity.
I saw a ground strap that failed just like this. The car started right up when we jumped it, but would not stat by itself. Batter was fine. Checked the ground strap and... BINGO.
There was also a guy at the Frenzy who had a loose battery terminal and the car would not start. Make sure that stuff in good, tight and clean.
I saw a ground strap that failed just like this. The car started right up when we jumped it, but would not stat by itself. Batter was fine. Checked the ground strap and... BINGO.
There was also a guy at the Frenzy who had a loose battery terminal and the car would not start. Make sure that stuff in good, tight and clean.
10-05-2009, 10:37 AM
#14
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Continuity testing doesn't always do the job, especially in cases like this. It is not unusual for a connection to show continuity, but not be able to pass the necessary current flow.
Many years ago a friend who was an excellent mechanic had major problems with his daughter's car - the engine would just stop at random, then it might or might not just restart easily.
After weeks of troubleshooting, it was obviously an ignition problem, but he couldn't find it. One day he happened to notice that the primary wire feeding the coil bent more easily in one spot near the coil. The copper had one strand that wasn't broken. The broken strands would touch and the car would run. When the wire moved and the broken strands didn't touch, the single strand could not carry enough current to fire the coil - but it still showed perfect zero-Ohm continuity, as he had shown time after time.
The battery strap could do the same thing. I suspect that a few minutes with a torch, flux and solder would take care of the problem.
Many years ago a friend who was an excellent mechanic had major problems with his daughter's car - the engine would just stop at random, then it might or might not just restart easily.
After weeks of troubleshooting, it was obviously an ignition problem, but he couldn't find it. One day he happened to notice that the primary wire feeding the coil bent more easily in one spot near the coil. The copper had one strand that wasn't broken. The broken strands would touch and the car would run. When the wire moved and the broken strands didn't touch, the single strand could not carry enough current to fire the coil - but it still showed perfect zero-Ohm continuity, as he had shown time after time.
The battery strap could do the same thing. I suspect that a few minutes with a torch, flux and solder would take care of the problem.
10-05-2009, 11:21 AM
#15
Electron Wrangler
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I wouldn't try to repair a ground strap in this condition - except as a purely temporary measure...
Remember these are made up of lots of very thin strands woven together to enable a very flexible strap... once these corrode (oxidize) there is a good chance that there is very little actual conductor left (just lots of oxide)... in this case heat and solder will only help to supplement the connection not to really repair it - it will also make the strap much less flexible which may be problematic anyway but will also create a new major flex point where the solder ends.
Alan
Remember these are made up of lots of very thin strands woven together to enable a very flexible strap... once these corrode (oxidize) there is a good chance that there is very little actual conductor left (just lots of oxide)... in this case heat and solder will only help to supplement the connection not to really repair it - it will also make the strap much less flexible which may be problematic anyway but will also create a new major flex point where the solder ends.
Alan