X20 Questions

[MauiM3Mania]

As we work at placing a S50B32 into our 04/99 production M3, we need a nudge as to what is what on both ends of the X20 prior to putting the two together.

The engine/harness came from a 1998 MZ3.

We're unclear on two points...

1> where does Pin 10 come and go to on either the US or Euro X20 connector.

2> same for Pin 14 at the X20 connector on the US car

We are not finding the answers in the ETM and a few other other diagrams. Where do these lines go to or come from?

Thanks

[tynashracing]

When I was doing my install...there was this guy named Matt that came through for me. This is what he provided and I'm happy to share.

I'm also surprised that the ETM doesn't show the X20. It does...but the info is buried in each component. Not really helpful. Anyway, here you go.

US E36 M3 X20 pinouts:

1 Not used
2 Not used
3 Not used
4 A/C compressor control
5 Normal speed relay
6 Climate control module
7 Starter immobilization relay
8 Not used
9 For Euro 3.0 M3 to oil temp gauge. Not used in US M50s
10 Reversing light switch
11 Engine temperature
12 Engine coolant temperature
13 Oxygen sensor, fuel pump relay
14 On Inst.cluster on rear of speedo, vehicle speed output
15 Wiper/washer module, body electronics control module
16 Data link
17 Data link DME
18 Starter
19 Service interval reset
20 Engine speed input RPM
21 Ignition switch to DME
22 Reversing light switch
23 Oil pressure
24 Instrument cluster, board computer
25 Alternator charge

Euro 3.2 X20 pinouts:

1 Not used
2 Not used
3 Not used
4 Air Con
5 Air Con
6 Air Con
7 Enable signal from EWS II module pin 4 to Motronic pin 66
8 Check engine light
9 Oil temperature sensor to Instrument cluster X16 pin 13
10 Reverse light switch
11 Coolant Temp sensor pin 2 to Instrument cluster X17 pin 17
12 Coolant Temp sensor pin 1 to Instrument cluster X17 pin 18
13 Fuel Pump Relay Terminal 87 to Fuse F18
14 Road speed signal from Instrument cluster to motronic pin 42
15 I am cranking' signal from Starter terminal 30h to OBC pin 8
16 Diagnostic Connector pin 15 (Diagnostic Data Link RX)
17 Diagnostic Connector pin 20 (Diagnostic Data Link TX) to EWS II module pin 2
18 Starter terminal 50 to EWS II module pin 1
19 Diagnostic Connector pin 7 to Instrument cluster X17 pin 15 (service reset)
20 Engine speed o/p from Motronic pin 47 to Instrument cluster X16 pin 20
21 Ignition Switch terminal 15 to Ignition coils & Motronic pin 56
22 Live in Run & Start from Ign switch term 15 via fuse 26
23 Oil Pressure switch to Instrument cluster X17 pin 19
24 Fuel Rate output from Motronic pin 46 to Instrument cluster X16 pin 21 & OBC
25 Charging Voltage (Alternator D+) to Instrument cluster X17 pin 6

[MauiM3Mania]

Whoa... great stuff. Thanks a load, Ken.

[tynashracing]

Whoa... great stuff. Thanks a load, Ken.

You're welcome. Good luck with the install!

[M3 Euro LTW]

Ken's got a 95 M3.

No traction Control, so there are no leads on there to modulate his TB from the old car.

Scott, you've got a 99. Its different as you know.

Also, I'm not sure if Ken is supplying an X20 for a coupe/sedan or for a Z3 harness, they will not be the same.

I thought I knew a lot about the ins/outs of these different permutations, but there were a lot of variations to keep track of.

Alex.

[avusm3]

Hi Maui -

So have you made progress with your install? I will be putting an S50B32 from a 1999 MZ3 into my 1995 US M3 in a few weeks and I noticed that the speed output from the DME (DME PIN 42) typically goes to X20 PIN 14 on our US cars engine harnesses but on the seems to go to X20 PIN 9 on the MZ3 harnesses. Have you moved this pin on your engine harness so that it matches the PIN 14 location on the X20 on your car?

Ken - thanks for breaking down the X20 for us.

Thanks,

John

[MauiM3Mania]

John,

It's progressing... we're down to the misc system updates/installs. (New oil cooler/lines, gauges and wiring, etc).

We did spend a good amount of time going through the wiring in order to be comfortable when it will all be plugged together.

The car and wiring diagrams are not here, but as I recall we didn't have to move the speed sensor at the X20, or anywhere for that matter.

Our car is a 99 and the engine/harness are from a 98 Z3. Our car and your 95 have different pin assignments.

Per Ken's list for the 95, the speed input/output seem to line up.

[tynashracing]

Ken's got a 95 M3.

No traction Control, so there are no leads on there to modulate his TB from the old car.

Scott, you've got a 99. Its different as you know.

Also, I'm not sure if Ken is supplying an X20 for a coupe/sedan or for a Z3 harness, they will not be the same.

I thought I knew a lot about the ins/outs of these different permutations, but there were a lot of variations to keep track of.

Alex.

Alex is right...my chassis is a '95. HOWEVER, I bought a '96 m3 coupe chassis harness for the installation. My S50B32 is from a '98 SMG. It was a fricken nightmare!!!

John,

It's progressing... we're down to the misc system updates/installs. (New oil cooler/lines, gauges and wiring, etc).

We did spend a good amount of time going through the wiring in order to be comfortable when it will all be plugged together.

The car and wiring diagrams are not here, but as I recall we didn't have to move the speed sensor at the X20, or anywhere for that matter.

Our car is a 99 and the engine/harness are from a 98 Z3. Our car and your 95 have different pin assignments.

Per Ken's list for the 95, the speed input/output seem to line up.

Hey guys, I've pulled a massive bonehead move. I stripped out my fuse box entirely and have hard wired into the X20 and EWS II.

The car will turn over. I'm getting the click sound from EWS. I'm getting power to all of my relays. However, the dme isn't allowing spark and fuel.
I've got 2 different dme's with keys. Neither will operate. So, I suspect I'm missing a wire or hooked something up improperly.
Here's what I've done: going from memory so I might be sketchy but can confirm everything when I get home.

EWS:

Pin 1 (black/yellow).....connected to X20 Pin 18(I think) black/yellow
Pin 2 (white/violet).....not connected to X20...this is for diagnosis
Pin 3 (green/black).....connected to ignition start switch
Pin 4 (small green)......connected to X20 pin 7
Pin 5 (red/yellow).......hot at all times
Pin ? (black wire).....connected to black wire on X20 and X16
Pin 9 (large black).....12 volts
Pin 13? (blue)...........connected to blue transmitter wire

Transmitter wiring:

violet/white?.....12 volts
brown..............ground
blue...............ews blue wire


X20

Pin 7........pin 4 on ews
Pin 13......15 amp fuse
Pin 21......direct from ignition switch (large green wires)
Pin ? (small black wire)....connected to pin ? on ews (small black wire)


What the heck am I missing? Is there anything on X20 that needs to be grounded for the dme?

Maybe I'm missing a power wire for X20 that tells the dme it's time to send for spark and fuel!?

I'm so frustrated. Everything worked fine before I hacked up the fuse box. The good news in all of this...once I get it running again....it's a lot lighter and neater!

Please help a brother out!

[gobuffs]

I didn't clean this up at all....I just looked at the ETK and looked for stuff that might help. It will get you started. First thing to check from this post is power OUT of the relays? And power to injectors and coils. Good luck.


I forget if you said you had an M3 or an MZ3 engine harness....will assume it is an M3 one.

A multimeter is your friend....

Clicking of the EWS is a good sign. Hopefully you have not unaligned it by swapping keys around.

You say you are getting power TO the relays....are you getting power OUT of the relays? For the DME relay this means both 87 sockets (or pins 2 and 5)- easy way to tell is are you getting 12v from all red/white wires on the relay? For the O2 sensor it is socket 87 or pin 2. Since you say it will turn over that means the relay to the starter must be working....but check it again (socket87 or pin 2 on start relay). On that same relay is the fuel pump. Are you getting 12v on socket 87 (or pin 7)? That goes to the fuel pump via pin 13 (green/violet) on the X20 and via fuse 18 (and then thru an X638 connector somewhere).

Are you getting 12v to the injectors? Are you getting 12v to the coils?

Pin 14 on the X20 connects the instrument cluster to the DME. You need this wire connected (small white with black tracer).

EWS 12 connects to X20 20.

[tynashracing]

I didn't clean this up at all....I just looked at the ETK and looked for stuff that might help. It will get you started. First thing to check from this post is power OUT of the relays? And power to injectors and coils. Good luck.


I forget if you said you had an M3 or an MZ3 engine harness....will assume it is an M3 one.

A multimeter is your friend....

Clicking of the EWS is a good sign. Hopefully you have not unaligned it by swapping keys around.

You say you are getting power TO the relays....are you getting power OUT of the relays? For the DME relay this means both 87 sockets (or pins 2 and 5)- easy way to tell is are you getting 12v from all red/white wires on the relay? For the O2 sensor it is socket 87 or pin 2. Since you say it will turn over that means the relay to the starter must be working....but check it again (socket87 or pin 2 on start relay). On that same relay is the fuel pump. Are you getting 12v on socket 87 (or pin 7)? That goes to the fuel pump via pin 13 (green/violet) on the X20 and via fuse 18 (and then thru an X638 connector somewhere).

Are you getting 12v to the injectors? Are you getting 12v to the coils?

Pin 14 on the X20 connects the instrument cluster to the DME. You need this wire connected (small white with black tracer).

EWS 12 connects to X20 20.

Thanks for the info Bruce. Yes, my harness is from an M3.

I know that I've got power coming into the relays. The only way I can get power to leave the fuel pump relay is to run a jumper. Fuel pumps operate at that point. Car still doesn't start. So, I'd assume no power to the coils or injectors. I will check the pins that you mentioned on the dme. I believe all the red and red/white wires have voltage at the relays but will double check.

I don't think I hooked up pin 14 white/black. I'll get that hooked up.

Not sure if pin 12 is hooked up to X20 pin 20.

I'll be able to check these tomorrow.

Thanks again for the help!

It's bound to be something really simple. I just get cross eyed looking at these schematics. I have a difficult time understanding where power is supposed to be coming in and what feeds it vs. when it's leaving to feed the relays or ews.

[tynashracing]

Well, all this time I've been hunting for ews issues. Finally got wise and decided to begin checking voltage on X6300 (harness connection to dme).

Testing resulted in no power showing at at pin 54...battery voltage from the dme relay.
So, after tracing the wire back to the relay, I decided to pull the relay and reattach. Checked voltage again and sure enough it was there. Attached the dme and with a flip of the ignition switch...the glorious sound of the fuel pumps filled my ears. Hit the push start button and the engine fired up immediately..

Cut it off to try it again. Huh, no fuel pumps. Went over and jiggled the wires and relay. Tried again, fuel pumps came on and car started.

Decided to spray the relay prongs with electrical parts cleaner, but after installing...I had the same problem. Went back, pulled the relay and reinstalled and jiggled the wires...fuel pumps were operating again and the car fired up.

What do you guys think? Faulty relay?

I'm just so thankful to have found the issue!

[Daytonas50]

When I was doing my install...there was this guy named Matt that came through for me. This is what he provided and I'm happy to share.

I'm also surprised that the ETM doesn't show the X20. It does...but the info is buried in each component. Not really helpful. Anyway, here you go.

US E36 M3 X20 pinouts:

1 Not used
2 Not used
3 Not used
4 A/C compressor control
5 Normal speed relay
6 Climate control module
7 Starter immobilization relay
8 Not used
9 For Euro 3.0 M3 to oil temp gauge. Not used in US M50s
10 Reversing light switch
11 Engine temperature
12 Engine coolant temperature
13 Oxygen sensor, fuel pump relay
14 On Inst.cluster on rear of speedo, vehicle speed output
15 Wiper/washer module, body electronics control module
16 Data link
17 Data link DME
18 Starter
19 Service interval reset
20 Engine speed input RPM
21 Ignition switch to DME
22 Reversing light switch
23 Oil pressure
24 Instrument cluster, board computer
25 Alternator charge

Euro 3.2 X20 pinouts:

1 Not used
2 Not used
3 Not used
4 Air Con
5 Air Con
6 Air Con
7 Enable signal from EWS II module pin 4 to Motronic pin 66
8 Check engine light
9 Oil temperature sensor to Instrument cluster X16 pin 13
10 Reverse light switch
11 Coolant Temp sensor pin 2 to Instrument cluster X17 pin 17
12 Coolant Temp sensor pin 1 to Instrument cluster X17 pin 18
13 Fuel Pump Relay Terminal 87 to Fuse F18
14 Road speed signal from Instrument cluster to motronic pin 42
15 I am cranking' signal from Starter terminal 30h to OBC pin 8
16 Diagnostic Connector pin 15 (Diagnostic Data Link RX)
17 Diagnostic Connector pin 20 (Diagnostic Data Link TX) to EWS II module pin 2
18 Starter terminal 50 to EWS II module pin 1
19 Diagnostic Connector pin 7 to Instrument cluster X17 pin 15 (service reset)
20 Engine speed o/p from Motronic pin 47 to Instrument cluster X16 pin 20
21 Ignition Switch terminal 15 to Ignition coils & Motronic pin 56
22 Live in Run & Start from Ign switch term 15 via fuse 26
23 Oil Pressure switch to Instrument cluster X17 pin 19
24 Fuel Rate output from Motronic pin 46 to Instrument cluster X16 pin 21 & OBC
25 Charging Voltage (Alternator D+) to Instrument cluster X17 pin 6

Reviving this thread, trying to get the wiring right on my swap. What do you do with pin 22 on the chassis to give pin 22 on the engine harness with out losing reverse lights?