Porsche 911 SC Wiring Repair Project

Spring has finally sprung in the UK. The weather here was a balmy 12 degrees this afternoon, so I took the opportunity to get stuck back into the jobs on my Varmint Porsche 911 SC after two months with no activity.

The last thing I touched on this car was the fusebox. The fuel pump relay wiring looked a little scary, as well as some very corroded main terminals on the battery, and some melted insulation in the ECU loom (the US cars run a little ECU). Today was all about repairing and digging a little deeper.

First job was to repair the fuel pump loom. I chopped out the solder blobs and installed DuraSeal connectors, with a few soldered joints here and there. Rough-looking wiring was replaced with matching genuine Porsche cable. The beauty of breaking a 924 and a 944 (and stripping out all the wiring) is I now have a lifetime’s supply of proper copper. I also took the fuel pump relay apart and found the contacts pitted and slightly bent. I cleaned and realigned all that and then resealed the cover.

Fusebox refitted, I got to sorting out the ignition switch feeds from the positive battery terminal – they were in a right state. To do it properly, I pulled the (huge) battery out completely and was relieved to see the tray and surrounding metal work absolutely rot free. This car is so tidy! I cut these out and replaced the lot.

Finally for today, I boiled up the battery earth lead to rid it of verdigris, dried it with heat and drowned it in switch cleaner. I tidied up the battery posts and terminals with my cool new battery tool, fitted a Dis-car-nect for safety’s sake and stripped all the earth points back to bare metal. Everything went back together a treat.

There was nothing much wrong with the way the SC worked before I took it apart but, as the pics show, it has a bit of classic old Porsche wiring syndrome going on, so it all needed doing. Hopefully I am adding reliability: if I can get it registered this week, then I am considering taking it to Germany for the Techno Classica in Essen in ten days’ time. Fingers crossed!

1 Comment

  • Stuart Smith says:

    Help I have a wiring issue or should it be a wire problem my 74 911 has had to have it’s cdi unit replaced along with its coil. The problem comes from how the coil is wired back into the wiring loom one of the wires is past it’s best so needs replacing it is a single core RF sheilded wire. The rub is I can’t seem to find anything like it? So if anyone can give me any advice or point me in the right direction.

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