Rexxus

Hello,

I was under my 89 S4 ROW looking at the oil pressure sensor and say this hole with a paper coming out. Is that supposed to be open? Didn’t seem to have threads for a plug…

while I was there I also saw this wire that looks frayed. I think it’s going to the ac compressor? The compressor spins when the car is on but my right fan doesn’t seem to work and my ac doesn’t either. Just wondering if anyone know what part that is and what wire that is and what’s it for?

thanks again

545svk

The frayed wire is connected to the starter motor. Will definitely need to be fixed.
The hole is on the cover place over the steering rack. Not sure what the paper is, but it won't cause your car to explode.
Nice clean underside.

FredR

Classic signs of buggered front of engine harness. The shredded cable is the 4mm2 cable that carries power to engage the starter motor solenoid and is supposed to have yellow insulation emanating from terminal 14 of the 14 pin connector next to the hot post. Suggest you undo the 14 pin connector cover and take a look at the cores just before and as they enter the connector to see what condition they are in. Chances are you will not be able to determine what colour some of the cores are. The power cables coming from the starter motor terminal also have the nice gungy looking brown colour indicative of what I refer to as "cable cancer". They are permanently live whilst there is juice in the battery and you do not want them going to earth unless you want a welding machine!

No idea what the streaky bit is but does not look like anything likely to harm your car- unlike the cable degradation that has plenty of potential. Simple test for the cables flex them- if the insulation shows signs of cracking or falling off do something about it- immediately,

Rexxus

Thanks a mil!

ok so for the oil pressure sensor wires, no need to go nuts as long as they’re not cracking when flexed. I’m thinking disconnect the oil pressure sensor, clean it, put heat shrink over the end and down to where that damage in the red wire is, maybe put a touch of dialectic grease where the wire is damaged, cut the end of the red wires where they go into the oil pressure sensor, strip to new wire, and thread through to pressure sensor, reconnect all and hope that fixes the oil gauge issue. Thoughts?

for the starter wire, seems like I have a bigger potential issue there. There doesn’t seem to be a lot of extra wire there and it goes into that thick red wire sheathing. Can it be patched or is the issue that because it’s frayed, it could cause an issue in the 14 pin and blow something? Cause a short?

from underneath the car, can I patch it? I’m thinking disconnect the battery, disconnect the wire from the starter, twist to tighten the wire threads, cut away stragglers, apply heat shrink, electrical tape each end of the heat shrink?

im kinda new to 928 ownership and car mech in general. I hear the 14 pin connector is like a brain for the car so I’m hesitate to mess around with it.

if you’re thinking not really a good idea for the diy job I described above, how many hours do you think it would take a mechanic to fix and what would I be asking? Change the wire from the 14 pin all the way to the connector?

thanks a mil

FredR

It is difficult to predict just how far gone the wiring is and doubtless some of it will be serviceable a while longer but obviously the previous owner made an effort to tidy things up and if nothing else the thing looks very clean underneath.

The ultimate solution is a new front of engine harness. Mine was in poor condition a few years ago and I built a new harness myself - it is not a difficult task but then it is not quite so straight forward either. Someone who knows what they are doing 928 wise can probably remove the old harness and fit a new one in 4 hours or so. A new harness is around the $700 mark plus labour I guess is going to round out around the $1k mark.

You simply need to evaluate the condition of each and every wire and that is not so easy due to being encapsulated in the harness. In my case the damage I found when opening the thing up prompted me to bite the bullet and replace all but a couple of cores that were fine and thus reused.

Rexxus

that makes a lot of sense. I think I’ll patch for now and monitor for problems. I intend to have the timing belt replaced in 2-3 years and will definitely ask the mechanic to evaluate the harness and replace is need be then. In the meantime if I start to notice anything unusual I’ll take it right away to have it evaluated.