Carpokes Porsche Forum

I wound up supplementing and running another ground close to the starter. Tested and cleaned all the connection points. Not sure what happened with the conductivity between the points but my motor was hot tanked and all that during the rebuild. I did test amperage draw the starter only pulls about 13amps

I'd be curious what happens if you pull the first ground.

Tom wrote: Wed Jul 02, 2025 6:51 am I'd be curious what happens if you pull the first ground.

I may try it. But the supplement wire I ran is only 6 gauge not the 2 I ran to the OEM ground point.

seiplej wrote: Wed Jul 02, 2025 12:34 pm

Tom wrote: Wed Jul 02, 2025 6:51 am I'd be curious what happens if you pull the first ground.

I may try it. But the supplement wire I ran is only 6 gauge not the 2 I ran to the OEM ground point.

I'd be too curious not to figure out what the issue is. This feels like one of problems where eventually you discover some issue and say 'aaahhhh, so that's what happened....'

seiplej wrote: Wed Jul 02, 2025 5:48 am I wound up supplementing and running another ground close to the starter. Tested and cleaned all the connection points. Not sure what happened with the conductivity between the points but my motor was hot tanked and all that during the rebuild. I did test amperage draw the starter only pulls about 13amps

Reminder from some electrical basics I learned in school only 50+ year ago now ---

-- The current you measure anywhere in the loop is the same any other place in the loop. So a high resistance anywhere in the loop doesn't tell you specifically about a wire you are 'testing'.
-- Clamp-on ammeters for DC are different than the one you might use for AC in residential electrics for instance. Make sure the tool you are using is in fact rated for measuring DC Amps.
-- Every 'resistance' in the loop reduces the current in the loop, and shows up as a voltage measured across that resistance. It might be a poor connection, a corroded wire, or some component in the loop. For some cars with external solenoid switches, this is important.
-- You can test the starter itself out on the floor to make sure it actually spins when energized. Use jumper cables.

-- Is the battery fully charged?

Since you can measure the resistance of any component in the loop with a voltmeter across it and current flowing through it, follow the basic guidance for measure the battery capability with a voltmeter between terminal clamps. Should be 12.6V fully charged but settled/at rest for 30 minutes. Your stated 13 Amps draw with starter engaged should cause a minimal drop in battery voltage at the terminal clamps. For grins, repeat the test with the meter connected to the battery posts rather than the clamps. The difference between the two readings indicates resistance between the post and the clamp.

Corroded cables, clamps and connectors cause a disproportional amount of grief especially in our somewhat vintage cars. As much as I claim to know about such things, stooooped stuff grabs the limelight sometimes. I drove around with meters and jumper wires strung through the cabin as I chased an erratic primary electrical symptom. Turned out to be a battery ground strap that looked great and showed no signs of problems when I had meter leads across it while starting and driving. After a new alternator, primary battery cables, and engine ground strap, I decided to replace the battery ground strap because I was running out of possible causes. Old one was corroded inside the protective sleeve, not found until I cut the original one apart.

Persistence paid off for me. Fortunately I can offset the time commitment against avoided couch time with a pro therapist. :rolleyes:

Tom wrote: Wed Jul 02, 2025 12:48 pm

seiplej wrote: Wed Jul 02, 2025 12:34 pm

Tom wrote: Wed Jul 02, 2025 6:51 am I'd be curious what happens if you pull the first ground.

I may try it. But the supplement wire I ran is only 6 gauge not the 2 I ran to the OEM ground point.

I'd be too curious not to figure out what the issue is. This feels like one of problems where eventually you discover some issue and say 'aaahhhh, so that's what happened....'

I was also curious. I was ohming out my cables and testing things and my stepdad was like just run the extra wire and get it running Lol..

seiplej wrote: Wed Jul 02, 2025 1:46 pm

Tom wrote: Wed Jul 02, 2025 12:48 pm

seiplej wrote: Wed Jul 02, 2025 12:34 pm

I may try it. But the supplement wire I ran is only 6 gauge not the 2 I ran to the OEM ground point.

I'd be too curious not to figure out what the issue is. This feels like one of problems where eventually you discover some issue and say 'aaahhhh, so that's what happened....'

I was also curious. I was ohming out my cables and testing things and my stepdad was like just run the extra wire and get it running Lol..

Sneak out after dark and get back to it. Assuming the laws of physics are upholding their end of the bargain, there are a pretty limited number of potential culprits. And if this helps with the step-father, it's better to find the real issue now on a nice summer day, and not wait until some snowy morning when the system can't handle the extra load.

Ok So back at testing. While the car was running both #6s one to the body and one to the lower bell housing were carrying 23-26a. The #2 had like 2-3a to the factory spot. I moved the #2 to the cam tower just to test and it started carrying the load at 26a. and the 2 #6s were down to like 11. So something is up with that factory ground point.

But on other news with this I was working on the AC and the clutch is bad and smoked my climate control panel.. So theres that too. The AC clutch was pulling 60a trying to engage when I tested it. Can you buy a clutch kit alone?