S50 Engine loom

[DanThe]

Does anyone have an S50 wiring diagram?
Ian332isport gave me a link to one that was hosted somewhere but ive lost it

Im trying to identify the engine loom to body loom connections

Ive guessed at this by using a standard E36 wiring diagram, but im not sure if there would be any differences for the S50 lump

S50 Pin No - Colour - Function

1-
2- Black/red........- oil level static
3-
4- Black/blue.......- Air con
5- Black/grey.......- Air con
6- Violet/grey.......- Air con
7- Black/violet......- Drive away signal
8- Grey ...............- ECU fault light signal
9- Brown/red
10- Blue/yellow
11- Brown/yellow....- Water temp
12- Brown/violet.....- Water temp
13- Green/violet......- Fuel pump
14- Black/white.......- Speed to clocks
15- Black/green......- Unloader relay
16- White/yellow.....- Rx data
17- White/violet......- Tx data
18- Black/yellow.....- Starter
19- White/green......- si reset
20- Black................- Engine speed to clocks
21- Green...............- Ignition
22- Green/white......- Ignition feed to diagnostic socket
23- Brown/grey.......- Oil pressure
24- White/black.......- Fuel rate to clocks
25- Blue..................- Alternator

Can someone in the know check it over,
Thanks

[Brianmoooore]

Ian's away for a couple of weeks, and I don't have the S50 diagrams, however comparing with M50 diagrams, the differences I have are:
1/ is oil level,dynamic.
2/ Oil level, static, but mine is blue/yellow. (check the colour at the sensor plug end)
3/ I have a red/white, which is just a power feed to the ABS from the main engine relay.
9/, 10/, I have no connection.
22/ is an ignition feed from pin 6 of the E30 C101. Only connects to anything when the lid is on the diagnostic socket.
All the rest are correct.

[DanThe]

No wire in Pins 1 and 3 Brian,

Thanks for no 22 though

[buster]

x20...................c101

25 BL................1 BU Alternator d+
2 GN/GE...........2 BU/BK oil level sensor static
7 GN.................3 GN enable signal from ews 2 pin 4 to motronic pin 66
12 BR/VI...........4 BR/VI coolant temp sender to instrument clust,c1 pin26
23 BR/GN..........5 BK/BR oil pressure switch to inst cluster c1 pin 18
22 GN/WS.........6 GN/YL Live in run&start from ign swith
21 GN...............7 GN start sig to motronic pin 56
24 WS/SW.........8 YL/WT Fuel output- motronic pin 46 to inst clust c1 pin11
20 SW...............9 BK enginespeed o/p frm motronic pin47 to c1 pin7(tach)
1 BL..................10 VI/GN oil level sensor dynamic
19 WS/GN..........11 diagnostic connector (service reset)
........................12 ------ not used
13 GN/VI...........13 VI/RD fuel pump relay to fusebox (fuse 11)
14 SW/WS.........14 BU/YL road speed signal to motronic pin42
15 SW/GN..........15 BK/GN starter unloader relays & inst cluster c1 pin 1
.........................16------not used
17 WS/VI...........17 WS/VI diagnostic connector pin 20 (tx) to ews 2.pin 2
18 SW/GE..........18 BK/YL starter sigfrom ign switch to solenoid,via ews2
9 BR/RT.............19 BR/YL oil temp sender to inst clustr c6 pin 2 (e30m3)
3 splice 6821 RT/WS..20 RD/YL main relay term 87 to abs pin 10


there you go.

cheers
andy

[buster]

x20,on the left pin numbers (from e36 m3)
c101 on the right ,e30 pin numbers

[DanThe]

Thanks Andy

Added to my confusion

Dont have anything in Pins 1 and 3, this is a 3.0 litre so no EWS,

Did you fix a new wire into Pin 3 then?

[Brianmoooore]

Buster's colours are for the E30 body loom, rather than the engine loom side of things.
E30s don't have EWS, so this must be an added in pin.
9 appears to be oil temp, which the M50 doesn't have.
Just leaves pin 10 and the missing pin 1, Oil level dynamic.
Pull the rubber boot back on the oil level sender plug and see what the colours are.

[buster]

the first number and colour are the x20 plug on the e36.
The second number is the e30 c101 pin number and colour

as brian said,Pin 3 ,17 and 19 are added to the c101 connector(body side) and pin 1 and 2 are added on the engine bay side of the c101 connector

[DanThe]

Thats another problem Brian, the loom is dissconected, not by me either.



Would expect the level sender to be at the rear of the engine on the S50, so this connector on the same branch as the O2 sensor connectors seems suspect, although the wires are Blue/yellow and Green/white



Will get my ohmeter out later and see what I can find

[buster]

oh dear you got trouble there dan.
Nope,that wire is either the reverse light wires or the gear position sensor wire.

[Turbo-Brown]

Gear position sensor?

These things have a torque limiter for 1st gear or something?

Won't be needing that!

[Brianmoooore]

You could be amusing yourself for an hour or two with that lot!
You know one of the oil sensor pins at the X20, so you should be able to find the oil level plug with the continuity tester function on your meter easily enough. That'll be one connector labeled. It's a start!!

[buster]

Gear position sensor?

These things have a torque limiter for 1st gear or something?

Won't be needing that!

Its a sensor so the ecu knows its in gear and ready to go (clutch in)
and not on idle.It apparently changes the fueling settings when on idle to when its in gear.Neither Ian or myself have this wired up as according to ian ,it makes no apparent difference.

Im pretty sure thats the reverse light switch wires,obviously not needed as you use the original e30 one.

[DanThe]

Its not that plug, I checked it out with the buzzer
I will check the others though

Looks like the loom will be taking a trip to see its engine tomorow

Loom looks bigger than it actually is because ive started to extend the ECU harness part while I wait for someone to post up a diagram for the x20 connector

[DanThe]

Im sure I read somewhere they have a rev limiter for first gear

Which is understandable really

[Brianmoooore]

Loom looks bigger than it actually is because ive started to extend the ECU harness part

That explains all the cut wires then!

[DanThe]

Just thought, if Pin 1 is empty and Pin 2 is a different colour then maybe the engine doesnt have an oil level sender?
Trip to the engine is defo needed



Also found this X20 chart

Thought it would be worth adding it to the thread

[DanThe]

Update, the engine never had an oil level sender which explains the difference.

Ive traced the Black/red wire from Pin 2 of the X20 to Pin 10 of the connector shown here, any ideas what it is?

[buster]

it should have an oil level sender,but it goes back to the ecu i believe.Unless the 3.0 doesnt have it.

[DanThe]

Deffo no sender in the sump buster, that white connector is on the same branch of the loom as the ECU connector, do you know what it plugs into?

[buster]

nope.On the 3.2,theres one like that but its yellow and its for the EWS

[DanThe]

EWS

[buster]

heres a pic,but like i said,its yellow and not white.

[jmc330i]

Yup, yellow one is for the EWS - same on my 3.0ltr.

I havent got access to my car at the moment so I cant check, but the white plug could be for the Vanos 'ECU'. The 3.2 has an all in one ECU, but the 3.0 has an engine ECU and a separate Vanos ECU.
Its been so long since I wired mine up, I cant remember what the plug looked like, but can check on Weds when I get down to the car.

The plug on the same loom as the 02 sensor plugs is indeed for the reverse light switch on the gearbox.

[Brianmoooore]

You said further up the thread that this isn't an EWS set up. Are you sure? Or did the 3.0 litre never come with it?
Post the ECU number on here, and someone might know if it's EWS or not.

[jmc330i]

You said further up the thread that this isn't an EWS set up. Are you sure? Or did the 3.0 litre never come with it?

Only the very last 3.0ltr M3s had EWS (from Jan '95 on), just like mine

[DanThe]

Cheers James

Seems like vanos ECU is the culprit then.

But why would it need a connection to the body loom

[jmc330i]

Pretty sure its for the Vanos controller.

TBH, it would probably be best to wait for Ian.
I do remember having a black/red wire on pin 2 of the X20 and having to ask Ian about it because it wasnt on the first set of wiring charts he sent me - they were for the M3 3.2 Evo.

I must admit, I cant remember what I did exactly because I also had to work around the EWS wiring.

[DanThe]

Looked at an E36 coupe with the S50B30 engine today and pins 1,2,3,4,5,6, and 8 have no connection on the body side of the X20 plug

JD

[orr]

That white plug goes into the vnc unit . it sits above the ecu and controls the vanos. EARLY m3 e36 around 94 do not have ews

[DanThe]

Yes mate thats right, ended up looking at an E36 M3 in the end

[ian332isport]

Dan,

I'm back now, so let me know if you still have questions

Cheers,

Ian.

[DanThe]

Sorted now Ian

Thanks