[ChrisZ]

Oi. It's going to be a month, isn't it?

So battery went bad on the 944S and I went to remove the cables. Of course the bolts are frozen solid and on the negative side the bolt broke right off... No biggie.

On the positive side the positive battery lug broke, valiantly protecting that ten cent bolt....



The word "Fuck" is appropriate here, I think.....

[linderpat]

The word "Fuck" is appropriate here, I think.....

Indeed it is

[ChrisZ]

Ok, calmed down, had a glass of eggnog, and ordered a new battery harness from Ian. $300 is a bit pricey, but the used ones will probably crack, break, burn the car down, and all that.

Quick question: Thoughts on putting it in? I assume it hooks up to ground points somewhere and either the starter solenoid or the alternator stud? Anything to watch out for on install?

Chris

[Scott at Team Harco]

Your knuckles.

[N_Jay]

Wrench on positive terminal and any part of the body? Maybe?

[ChrisZ]

I was thinking more of how to route the cable: I assume the wire goes down behind the engine, then across the driver's side to the starter solenoid. But how is it held up? Can I cut the old cable, tape/secure it to the new one, and pull it through? Do I need to pull the intake?

I think I'll replace the positive one this winter and leave the negative till the spring.

Meantime the nuts that hold all of the secondary cables to the positive lug are rotted as well, so hopefully the new cable comes with new 10mm bolts :-)

[ChrisZ]

Digging in today. Have the car up on the ramps, chocked, and went under it to disconnect the positive from the starter. Tugged the cable, no luck.

Turns out there is a cable harness clamp above the starter holding it on. Great. Pulled starter and dropped it. I can see that the battery cable does go onto a stud with the alternator harness cable as well, that explains how +12 goes from alternator to battery.

Taking a break to walk dog, will continue in the afternoon. Hopefully I can figure out where the negative cable goes on the engine...

[N_Jay]

Is there a problem that cutting and splicing ends won't fix, or is this a show car?

[ChrisZ]

Ok. After a few hours under the car, in incredibly cramped circumstances, and a minor amount of profanity I:

Got the starter off
Removed the bottom clamp holding the battery cable
Tried to remove the battery cable, would not budge. Probably has ANOTHER clamp at the top somewhere
Said "Screw it" and threaded the new cable down alongside the old one.
Secured it at the bottom with the cable clamp
Cleaned all the connections at the starter, put on some dielectric grease
Got the bolts started on the starter wire connections
Got the starter back in and threaded bolts and torqued down.

At this point I have way too many wires trying to go through the hole to the battery compartment so I do need to replace the negative cable as well. Porsche sticking brake lines right in front of that access hole is just cream on the cake.

The new battery cable is amazing. Porsche made, beautiful, here's a pic...


However, once again I can't figure out WHERE THE GROUND WIRE ATTACHES TO THE ENGINE. Looks like it goes down on the passenger side by the battery, then vanishes.

So:
Do I have to get to the ground from the top of the engine or bottom?
It is on the head or the engine or the flywheel bellhousing?
Is it on the driver's side of the engine or passenger's?



I'm thinking it's not from the bottom, but I may have to take off at least the injector rail to get to it. Not the worst problem, but if I have to pull the entire intake that would be a pain. Still, easier than working on the bottom of the engine...

Thoughts?

[ChrisZ]

Is there a problem that cutting and splicing ends won't fix, or is this a show car?

Well, it's a good car and has served me well for over 30 years now. I figured I should do it "right".

I wouldn't splice the positive end because it's unfused and if the splice ever wore through it would be worse than a catastrophe.

Negative side.... well maybe I will cut the negative, put a lug on it, and bolt connect it to the new negative cable. Problem there is if the negative ever lifts to the motor the DME would pretty much blow up instantly (as the system would try to ground through the DME wires) and probably toast the harness. I could put in a second ground as a backup, and of course if the ground wire touches ground it's not a big deal.

So.... if I can't find the negative line there I will splice that and wait till spring to pull the intake (to find that positive clamp that's still there somewhere) and find the negative ground point.

[N_Jay]

I guess I trust my splicing more than you trust yours.

[ChrisZ]

I guess I trust my splicing more than you trust yours.

I guess so. You be you.

Well done for now, after not being able to find the negative lead I gave up and re-ran the original negative side over the top of the firewall and re-terminated the ground on the firewall. It was a mess, cleaned the bolt on the wire wheel/grinder, then cleaned up the lug and the car part with a wire brush, followed by yet more dielectric grease and a proper torque down.

Got a set of battery clamps from Advantage parts, noticed that they have two bolts on top that could have been the spot to attach the extra positive wires, ignored that thought, and tested the wires for current draw. Good news: The alternator/starter line shows no current draw so no shorted/damaged diodes (good). The other three wires show 10ma and 30ma draws for a total of 40ma sleeper current, probably the radio and ok.

Hooked everything up, fired up the car, no problems, battery voltage went from 12.7 to 14.1 which means it's charging properly. Took it off the ramps and put the 928S up so I can fix the spoiler and the window lift. Never ends...

I'll work on the car again in the spring. I think it would be a hoot if I have to pull the engine to get to that grounding wire. Or I could pull the head, but that might be more of a pain. Hm....

[Scott at Team Harco]

You actually need to remove the head prior to pulling the engine, on the 16v. Or... rewire everything that goes between the head and the cam sprocket cover.

There is nothing easy about the battery cable routing. That's why I said; 'watch your knuckles'.