New member from the mountains...
Search for 'Dwayne's Write Ups.' He has done many well documented procedures on how to work on a 928.
As well, cough up $80 and get the Moorehouse CD set from Roger Tyson at 928s R Us. It contains all the Workshop Manuals, Electrical diagrams, PET (parts manual), plus a whole lot more for the 928. Worth having.
Welcome to the tank, and good luck!!!
Thanks for the info...
Here is what he found
1988
C02
M28.42- engine serial # range 81J 05001>10000
A28.12- 4-speed automatic with LSD, serial # range A 2812 2J 10001>20000
M018- Sport steering wheel with elevated hub 30mm
M139-Adjustable Seat Heating - Left
I158- Blaupunkt Reno SQR46
M220- Limited Slip Differential, 40%
M340- Seat heating - Right
M383- Sport seat - left, electrical, vertically adjustable
M387- Sport seat - right, electrical, vertically adjustable
M418- Protective side mouldings
M474- 1986.5-up Boge GZ twin-pipe gas shock absorbers, Fire Red (RAL 3000 paint)
M494- 87-88 Additional amp Blaupunkt BPA420
M533- Alarm
M570- Rear A/C
M650- Sunroof
I actually used the seat warmer last night and it works great, as I was doing a little late night mountain twisty driving..lol Gets the bum nice and toasty
Hickory is nice. I'm blessed to have the opportunity to live here. I actually took it out for some late night driving on the mountain I live on. Wow, this car handles like a go cart on rails..
The Best Porsche Posts for Porsche Enthusiasts
You were smart enough to post pics at the start, so we won't have to tease you about it.
As you noticed, rear carpet isn't factory. It looks like a Lloyd's. Factory doesn't have the "928 S4" logo AFAIK.
Sunroof issues are likely the switch. New ones are available, or the old one can be cleaned up and maybe made to work. If not the switch, there's a very complete writeup in the "New Visitor" sticky. As suggested, reading that will answer a lot of your questions. Just saw the other thread on the sunroof.
Fog Light switch sounds like it's simply broken. It should go in and come a back out a bit for "on". New or used are available.
Hatch release is a bit complex. Can you hear the motor run? If so, there's a part that wears out and develops enough play that the "pusher" wont' release the latch. there are a couple of fixes for it. If not, do your interior lights work? Seriously. The interior light circuit is part of the circuit. They have to be on for the hatch to release.
Do the records show a timing belt/water pump replacement? How about fuel lines?
If not, they should be done before driving the car. TB/WP can wreck the engine if it breaks and the valves crash into the tops of the pistons. Fuel line can destroy the entire car in what is known as a "carbecue."
Details and writeups on both of these jobs are on here.
You were smart enough to post pics at the start, so we won't have to tease you about it.
As you noticed, rear carpet isn't factory. It looks like a Lloyd's. Factory doesn't have the "928 S4" logo AFAIK.
Sunroof issues are likely the switch. New ones are available, or the old one can be cleaned up and maybe made to work. If not the switch, there's a very complete writeup in the "New Visitor" sticky. As suggested, reading that will answer a lot of your questions. Just saw the other thread on the sunroof.
Fog Light switch sounds like it's simply broken. It should go in and come a back out a bit for "on". New or used are available.
Hatch release is a bit complex. Can you hear the motor run? If so, there's a part that wears out and develops enough play that the "pusher" wont' release the latch. there are a couple of fixes for it. If not, do your interior lights work? Seriously. The interior light circuit is part of the circuit. They have to be on for the hatch to release.
Do the records show a timing belt/water pump replacement? How about fuel lines?
If not, they should be done before driving the car. TB/WP can wreck the engine if it breaks and the valves crash into the tops of the pistons. Fuel line can destroy the entire car in what is known as a "carbecue."
Details and writeups on both of these jobs are on here.
I took apart the switch and cleaned it and it will open it every time, just not close it so theirs either a loose ground or switch, the switch is very stiff and doesn't seem to make a good contact so Monday I'll just order a new one.
I just checked and interior lights don't work. Dash lights work but none of the courtesy lights. Later this afternoon I'll go in the hunt for the fuse box.
Timing belt was replaced 8 years ago
Water pump was replaced 9 years ago
Fuel lines are not mentioned anyway. Let me go look that up and save the how to..
I have heard that they sometimes have been known to burn to the ground because of pin holes in the fuel lines and all the pressure squirting gas everywhere. The motor looks great though, no oil leaks, drips or smell of fuel anywhere, transmission also has no leaks nor the gear box/diff
Thanks for all the helpfull info. Really appreciate it
Alan has created diagrams for most of the years. There's a thread here:
https://rennlist.com/forums/928-foru...all-years.html
Make sure you are using the correct year. The electrics varied quite a bit over the years.
Interior lights could be the fuse, could be a switch. Could just be that they are all turned off (each individual light can be turned off). They should come on with either door or the hatch open. Also, there are little red lights in the backs of each door. Those are on the interior light circuit.
The fuel lines are a bit more 'abrupt' than pinhole leaks. What happens is that the 30+ year old lines get brittle. The lines themselves are hard plastic inside the rubber cover. The plastic can let go catastrophically with no warning. This dumps large amounts of fuel on the hot motor, often creating a fire. There is no way to inspect or test the fuel lines. Its just suggested that they be replaced.
Very, very nice replacements are made by Greg Brown. Perfect fit and lifetime warranty. Sold both by him and through Roger Tyson at 928s R Us.
Updated engine refresh. Still have a bit to go.
Before...
After.. Have to touch up a couple places
ordered hood struts, hood carpet top/bottom and replacement stickers
They don't filter anywhere near as well as the paper ones, and the oil in them is believed to be bad for the MAF wire.
If you get the standard paper one, make sure you put it in with the 'hump" facing up.



