Easy question!

BackintheFold · 25-02-19, 07:01 PM

On my MB engine, at the back of the head (near the firewall near the distributor) there are three unconnected tubular connectors each with two wires.
There are two connectors close together which look like they are supposed to be joined-

One has a purple/black wire, and black.
One has blue/black wire, and black/grey.
EDIT this is the reverse light wiring.

There's another connector nearby with two wires, as well that I couldn't see any colours! I will edit later when I have more time to get a decent look.

There is also a 1cm wide hole at the top (right at the top-12 o'clock position) of the engine/gearbox where they join with a smaller hole that looks like it is a fixing screw/bolt hole.
EDIT-This is a hole for a sensor that is not used on the MB.

It is empty in my car which is non running, I wonder whether it is a hole for a TDC sensor, or if it should be plugged up. I have two other sensors on the same join, under the master cylinder.

Please can someone with a running MB Engine let me know what connectors are joined, and if there is anything in the hole? I have the day off on Monday to work on the car, so any suggestions at the weekend would be greatly appreciated.
Many thanks
Stuart

BackintheFold · 26-02-19, 09:39 AM

Just to note-the Bentley manual does not cover wiring for the MB, and neither does the Haynes manual.
If I knew what the wire colour combinations were used for, I could trace back/work out what to do, but I don't want to connect wires together that are unrelated and cause other issues!

I still need to figure out how to post pictures-when I have, and when I can get a shot of the area, I'll post back again in case it helps explain my question!

mikes2 · 26-02-19, 10:12 AM

Do you have the small bracket which holds the 3 wiring connectors next to the brake master cylinder ?

That's where the timing sensor connectors attach - there's also another one for the brake pressure switch.

They're not round though

For wiring diagrams, Phil Payne's website is your best bet. Hope your German is up to scratch

http://www.sealtd.net/quattro/ishamr...ing/index.html

You can't upload pictures on here. You'll need to host them elsewhere and link to them

BackintheFold · 26-02-19, 11:07 AM

Thanks for the reply Mike!
I do have the bracket, those are not the same connectors-as you say, they are square, these are round (tubular!).
Sealtd's mirror of Phil's website is very useful in many respects, but for some reason the MB wiring diagram is very dark and low contrast-I have tried to find a reference to a purple/black wire (LI/SW) in the MB area and some of the other diagrams, but it means looking at every wire-they are not reverse-indexed by colour and track (sadly).

I will take a picture soon of the area-it is obvious when you see it...

EDIT-I may have found it-track 57/58, fuel gauge sender wire(weird for the connector to be in the engine bay-will confirm later)
EDIT 2
OK, the hole in the gearbox casing is unused in the MB. Is for a Hall sensor
One connector may be unused (part of the braking system wiring and is shown as not connected on 7zap wiring diagram)
other two connectors may be suposed to be joined, and be for the fuel level sender-to-gauge.
I'll check out more later
EDIT 3 it's the reverse switch. Connect ed it back up and the reverse lights work.

26-02-19, 10:12 AM	#3
mikes2 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: Polmont Posts: 2,617	Do you have the small bracket which holds the 3 wiring connectors next to the brake master cylinder ? That's where the timing sensor connectors attach - there's also another one for the brake pressure switch. They're not round though For wiring diagrams, Phil Payne's website is your best bet. Hope your German is up to scratch http://www.sealtd.net/quattro/ishamr...ing/index.html You can't upload pictures on here. You'll need to host them elsewhere and link to them __________________ 1991 90 quattro 20v sport 1991 90 quattro

26-02-19, 11:07 AM	#4
BackintheFold Senior Member Classic Audi Club Member Join Date: Feb 2019 Location: Near an MB ur Quattro Posts: 1,171	Thanks for the reply Mike! I do have the bracket, those are not the same connectors-as you say, they are square, these are round (tubular!). Sealtd's mirror of Phil's website is very useful in many respects, but for some reason the MB wiring diagram is very dark and low contrast-I have tried to find a reference to a purple/black wire (LI/SW) in the MB area and some of the other diagrams, but it means looking at every wire-they are not reverse-indexed by colour and track (sadly). I will take a picture soon of the area-it is obvious when you see it... EDIT-I may have found it-track 57/58, fuel gauge sender wire(weird for the connector to be in the engine bay-will confirm later) EDIT 2 OK, the hole in the gearbox casing is unused in the MB. Is for a Hall sensor One connector may be unused (part of the braking system wiring and is shown as not connected on 7zap wiring diagram) other two connectors may be suposed to be joined, and be for the fuel level sender-to-gauge. I'll check out more later EDIT 3 it's the reverse switch. Connect ed it back up and the reverse lights work. Last edited by BackintheFold; 12-04-19 at 08:14 PM.

26-02-19, 09:39 AM	#2
BackintheFold Senior Member Classic Audi Club Member Join Date: Feb 2019 Location: Near an MB ur Quattro Posts: 1,171	Just to note-the Bentley manual does not cover wiring for the MB, and neither does the Haynes manual. If I knew what the wire colour combinations were used for, I could trace back/work out what to do, but I don't want to connect wires together that are unrelated and cause other issues! I still need to figure out how to post pictures-when I have, and when I can get a shot of the area, I'll post back again in case it helps explain my question!