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Digging into butchered electrics on this. What is the XVI relay position used for? The owners manual says "not connected". Some posts in the forum seem to suggests it's related to the alarm system. My factory wiring diagram seems to suggest it's related to the "AFC Relay". I've attached picture of what PO has wired at that location. I have no problem starting the vehicle or running in the workshop, but it is far from road worthy for a more detailed test.
If this is a US car with L jet, this would be for the fuel pump.
Sorry, typing to fast, meant fuel injection
If this is a ROW with K jet, I don’t think it is used.
It is US model with L Jet...
But both the owners manual and the wiring diagram say the fuel pump relay is in position XVII, not XVI...
That being said, I sense that the jumper wires in my picture were a attempt to bypass something, but I'm still wondering what they are bypassing? There is an odd wire running directly out of the front of the relay panel at position XIV that is not stock, which I haven't traced yet.
Looks like that's the Fuel Injection relay spot. Is that correct? The FI relay is known to fail with age, and when it does the car won't run. Perhaps a previous owner stuck that jumper in as a bandaid rather than buy an inexpensive relay. I won't hazard a guess as to the exact pins involved here (although you could certainly figure it out from the wiring diagrams referenced in the first thread).
I'd recommend you contact Roger, obtain the *correct* relay (and consider replacing all the at least "important" relays while you're at it if condition is unknown), and throw that jumper in the trash!
I'd also recommend you remove the entire central panel for cleaning with DeOxit and a thorough inspection before going much further if you have electrical gremlins. Remove all fuses, relays and block connectors, inspect (including for any melted wires or evidence that anyone has been messing in there), clean, ensure you have bright metal at all contact points, squirt with DeOxit, reassemble.
Further advice: There's a thread about doing the annual "ground maintenance" on the groundpoints, so another thing for your checklist if not already done. And these cars are so old that some of the harnesses have started falling apart, exposing wires and causing shorts and other problems. This is particularly the case with three underhood harnesses: the main engine harness (running along the passenger and front sides of the engine compartment), the front-of-engine harness running to the starter and alternator, and the fuel injection harness. I've replaced all of those on my '83, similar to your '80 in most respects. I've also replaced both battery cables and the engine-to-chassis ground cable. More things to think about. And add that to fixing whatever butchery is already on the car.
Turns out someone who owned or worked on that car knew more than some of us (including me) with that jumper. Sometimes I love having K-Jet and not having to deal with any sort of electronic fuel injection.
Interestingly, they fixed the owner's manual in 1981. A quick glance shows that not a lot else changed, but they do label XVI as the "EFI control unit" relay in '81. Of course even in the 1980 manual, the picture SHOWS a relay in the XVI position. Also, note that in the 1980 manual they don't label ANY relay as the EFI relay, which is clear error. 1980 was the first year of the L-jet, so kind of makes sense that an error like that could creep in.
Hey, bugs happen, not a big deal. This is not the first or the last Porsche documentation glitch.
XVI relay position
