Transmission Ground Strap Condition

[SpenceRx]

I’m still troubleshooting my recent no start but haven’t had time to spend with it. The car is driving and starting after charging the battery on my CTEK. It did no start again but this time I had my boost pack handy and the car started when connected to that.

Getting a new AGM battery this week but I think it’s a charging issue. Battery tested with a multimeter at idle was 11.86 volts. I didn’t have a helper to apply some throttle but will this week.

I crawled under the car today and found the transmission ground strap. Seems tight in there. Does this one look in need of replacement? I think yes.

[PeteKz]

Do you mean it is not starting, or not cranking? I think you mean not cranking.

The ground strap is not causing your no-crank. You proved that by starting it with the booster pack (I assume you connected it to the battery terminals). While you are under the car, it's a good idea to loosen it, wiggle it, and tighten it back down. Also remove, clean, and retighten the battery terminals.

Get someone to rev the engine to 2000. If the voltage does not come up to about 14V, you have a bad alternator or voltage regulator.

I also suspect the battery. How old is it? If fully charged on your C-tek, it should hold 12.6 volts for at least several weeks. If it doesn't hold the charge, it's most likely a bad battery, but also check for a parasitic current drain.

[SpenceRx]

Pete. Yes cranking.

New information. I took the battery out and can now see it was produced Jan 2020. I took the battery to an auto parts store and they bench tested it and the report was that the battery is in great shape. Bosch S4.

I’ll clean the battery terminals and connectors then reinstall. After that I’ll get a helper to rev the car to 2000 rpm to see what charge voltage I’m getting.

[76FJ55]

there appears to be a significant amount of corrosion on that ground cable, so if it were me I'd go ahead and replacer that as well, especially since you are having electrical issues.

[tperazzo]

The correct way to diagnose a bad starter ground strap is to measure the voltage drop across the strap while cranking.
Attach long leads of a voltmeter to each bolt on the ground strap. Don't remove anything, just attach alligator clips to the heads of the bolts.
Watch the voltage while cranking the engine. You should have less than .1V while cranking.

Repeat this test for the battery to body ground strap.
Or until you find the problem.

[Bill Douglas]

I thought my ground strap on the SC looked a bit dodgy.

So I put an extra ground strap on from the motor to where the engine mount is. The strap resembles a battery ground cable.

[ant7]

Remove the ground strap, thoroughly clean the chassis point and gearbox point, clean the ends of the earth strap, put some copper slip on the eyes of the strap, bolt it back up, job done, no point messing about, I had similar issue years ago, all good since!
Hope this helps.
Ant.

[kltarga72]

Originally Posted by ant7

Remove the ground strap, thoroughly clean the chassis point and gearbox point, clean the ends of the earth strap, put some copper slip on the eyes of the strap, bolt it back up, job done, no point messing about, I had similar issue years ago, all good since!
Hope this helps.
Ant.

Plus 1
Clean ground connections are mandatory. Corroded ground connections will cause a lot of intermittent electrical issues.

Ohms Law, E=IxR When resistance increases current decreases voltage stays constant
E = Voltage
I = Current
R = Resistance

[KerryM]

I recently cleaned up and replaced the transmission ground strap. It was easiest for me to remove the transmission mount bar/plate to do this. And with it removed, it was a great time to replace my old crusty transmission mounts.

[eastbay]

Don't forget to check the ground strap up front, at the battery. Usually overlooked.