1980 VW Cabriolet Project Car (Powered Up) Part 2

The Dub did not run when it was brought into the shop. There are basically two components needed to get a gasoline engine running - Spark and Fuel. If it sounds simple, it is! This Hub focus' on the electrical repair of this project car.

After getting the little car in the shop, I first checked the cylinder compression - 150 psi per cylinder, well within factory specs for a new engine! I then purchased the most expensive part the car will ever need (I hope) - a battery ($100). We hooked it up but the car was TOTALLY dead - NOTHING worked! VW's are known for bad grounds and faulty wiring so we disconnected everything and hooked up only the starter, coil, and ignition - then using a second battery, we jumped the fuel pump. Voila! The car started and ran great! For $150, I had found a good running little car - yet why wouldn't anything work?

A little more investigation uncovered a multitude of problems and solutions. If you too are struggling with electrical problems in your Rabbit (and what Rabbit owner isn't?), then perhaps the following scenario will help:

CLEAN: All the fuse ports and terminals on the fuse block were rusty or corroded. A wire brushing cleaned them up and restored electrical contact. Above the fuse block were two ground "crowns" where everything inside the car was supposed to ground. It too was rusted and corroded. I solved my ground problems by running a ground wire from the batter to the engine - then from that point to a bolt on the firewall - then a ground strap from the bolt on the inside of the car to the ground "crowns" (for lack of a better term). This created a heavy ground connection from the fuse block to the battery - no more voltage drop!

REPAIR: Under the hood was another mess of wiring to solve. Some other "shade-tree" mechanics idea of how to solve the cars grounding issues was to combine all the cars grounding wires into one HOUSEHOLD WIRE NUT!?! At first I thought it was a terrible idea, but it seems to work so why mess with it? That scattering of cluster-fornicating wires in the background of the first picture below is what really got me worried - you should never see wires floating around over your engine like that. In the following close-up of the wires you can see where a mystery wire has melted (probably from a short) and left behind the slag of its wiring insulation! It burned a lot of other wires and I spent several evenings cutting and patching all the shorted and corroded wires I could find. Hopefully I got them all.

Once all the bare wires were removed and spliced and the fuse block was repaired, we tried to start the car again but STILL no power to the fuel pump. A little more investigation and we realized that the melted wire was completely missing - and it was the power wire to the cars fuel pump. No wonder the guy I bought it from could never get it to run (he'd bought it from someone else with the idea of getting it to run). Whoever shorted this out simply cut out the shorted wire (fuel pump) at the fuse block! I hadn't noticed it before, but in the messy picture of the fuse block, you can see the "A" harness (white square plug) is disconnected AND missing the green/black fuel pump power wire (it should be in front of the blue wire on the left).

The solution was to replace the missing fuel pump power wire. I just happen to have a lot of extra wiring from my college days (when I used to screw up my own car stereo systems) so I spliced in a new hot and ran it directly to the main fuel pump. I routed it down behind the engine, through the A-arm, and along the fuel lines back to the pump. To keep it from shorting out again, I wrapped everything in a wire loom.

PROTECT: Prior to my meddling, there was only the bare, partially melted cluster of wires coming through that firewall. The large loom now holds that mass of wire. My loom is now routed now around the shock tower, beneath the fuel lines, and just below the air filter and fuel distributor (on left). The small loom running off to the left is the fuel pump wire which now runs down and under the car along the fuel lines (yellow zip-ties around it). The engine harness should be routed below the radiator. Before this was fixed, it was damaged by the exhaust, cooling fan, and alternator belt. Now the washer fluid pump, horns, lights, and charging system all are working again, but not before I wire-brushed every connector, light bulb and socket on the car. For some reason, everything is corroded - even the alternator housing. My guess is that this car took a salt-water bath at some point in it's long life....

RESOURCES: The Bentley Service Manuals have been an invaluable resource for this project! The Haynes and Chilton manuals aren't bad but don't clearly detail the wiring of these cars. The Bentley manuals have a very detailed wiring diagram, a fuse block diagram, harness diagrams, and corresponding numbers so you can determine where the wiring diagram meets the fuse block, harness, pins, and relays - very very handy.