E30 M3 wiring

[PiercedE30]

Wow..........you guys got DEEP into the wiring. When I made my adapter, I just looked at the functions for the pins at the C101/X20 and then matched them together.

[FredK]

Yeah, it's easy to wire up the late cars because you don't need to pull anything from C104, find a road speed signal, or monkey around with the starter / unloader relays.

[BigD]

So I found out that the car is a 1/87. So it looks like I'll be looking at the same problem as Jason. I've tried looking at the ETM and while I can make heads and tails of the individual diagrams, the PDF isn't searchable and I don't see any connector explanation diagrams (ie this pin is for that). There are some diagrams which have a connection labelled as c101 and I don't think I saw any pin numbers.

I know you guys don't want to hold my hand through this but can you please give me some more info on this unloader relay deal? And any other way, Jason, you remember your wiring being diff from a normal E30?

Thanks in advance for any help

[Mike B.]

You need to trace the wire back from the 'C101' connections that you are seeing to determine it's function. There should be a corresponding pin number directly opposite of 'C101' label.

Just dig through the full set of diagrams for the '87 until you have all of the pin functions determined. Put together a rough pin chart (matchup the x20/c101) and have us comment and make suggestions on what you have created.

The one shown earlier in this thread would be a good start and something to 'reverse engineer'.

[BigD]

Hokai, cool, thanks. *opens Excel*

[BigD]

Alright, first snag...

For pin 6, the chart says O2 relay. Jason says it's actually integrated with the fuel pump (which I see as pin 13 on the ETM). According to the ETM I'm looking at, it's the purge valve relay. Any suggestions guys?

[Jason89i]

Alright, first snag...

For pin 6, the chart says O2 relay. Jason says it's actually integrated with the fuel pump (which I see as pin 13 on the ETM). According to the ETM I'm looking at, it's the purge valve relay. Any suggestions guys?

thats actually the power for the evaporative purge valve. power comes through the fuse box, through c101 pin 6, and over to the evap purge valve relay. the left side of the relay is the magnetic trigger (getting the trigger signal from the dme) and the other side of the relay is the switch. the left side of the relay tells the right side (swithc) when to open / close. relay switch then allows power to go to the purge valve.

see page 1364-3&4. find the o2 relay / fuel pump relay and you will see how its integrated. power comes from the fuel pump relay and splits. one goes through the c101p13 and to the fuel pumps (1364-4) , the other goes directly to the o2 sensor heating element (1364-3). with the s14 engine removed, the c101p13 is just needing power from the s50 fuel pump relay.

on a side note.....there is some confusion as to if these diagrams are completely correct.

hope this helps.
cheers, jason

[BigD]

thats actually the power for the evaporative purge valve. power comes through the fuse box, through c101 pin 6, and over to the evap purge valve.

see page 1364-3&4. find the o2 relay / fuel pump relay and you will see how its integrated. power comes from the fuel pump relay and splits. one goes through the c101p13 and to the fuel pumps (1364-4) , the other goes directly to the o2 sensor heating element (1364-3).

cheers, jason

Hi Jason,

I know I saw that one, that's why I said I'm confused because in the diagram I saw pin 13 as being the o2/fuel pump relay wire, not pin 6, as I thought you said earlier, and as the chart says that Fred posted... I think in your case, I misunderstood what you said. It sounded like you were saying the pin 6 function is listed incorrectly as in incompletely - it says o2 relay but it's o2 and fuel pump - but you were really saying it's wrong altogether, that function is pin 13. So I should ignore pin 6?

Then the chart also says to wire the o2/fuel pump relay lead from the E36 harness to pin 15... shouldn't that be 13?

Thank you!
D

[Mike B.]

You are correct, it's x20 pin 13 to C101 pin 13 for the fuel pump.

[Mike B.]

From the looks of the ETM diagram, you sould be able to ignore pin 6 (c101).

The E36 S50 purge valve isn't wired in through the x20 and everything of interest E30-wise is on the engine side (which is being removed).

[Jason89i]

........ but you were really saying it's wrong altogether,.......... ?
D

yep, correct. i am saying that the online diagrams.....well....are all trash. (hey fred, there's a good quote.)

my response was really in jest. poking holes in these "s50 swap pin charts" has become one of my hobbies.

in all honesty, im glad to see you're cracking the books and doing your homework!!! im confident you will have a lot less issues.

mike is correct.

cheers, jason

[FredK]

Well, there aren't many online diagrams that I know of, especially for early-body cars or the 318is, and a lot of 'em are just recycled information originating from one source--AKG.

Nothing beats having the electrical manuals and tracing wires yourself. It's fairly straightforward of an affair, and the best part is, you're not getting your entire forearm greasy by sticking your hand up into some random recess of the engine compartment. Instead you're breathing in solder flux fumes. :mrgreen:

The peace of mind to know that your wires aren't going to go up in smoke the first time you start it is nice.

[BigD]

Jason, so this M3 looks like it's the same as yours, and 18 is the unloader lead. Should I wire it to E36 pin 15?

Also guys, I can't find C101 pin 11 on the diagrams. I know it's just the service indicator reset but it's on the pin chart and I can't find it on the diagrams...

[E30 2 ENVY]

question for you guys

I have been hunting all night to try to figure out a few wires for a 1990 e30 m3 with airbags that we are putting a OBD1 converted s52 into ( harness is off a 1993 325is ). I am stuck on four wires for the e30 harness.

On c101

#6 - Green \ yellow stripe - do I need to connect this to anything
#15 - Black \ green stripe - whats this for and do i need to connect it to anything on the e36 harness
#16 - White \ Black stripe - sames as #15
#20 - Red \ yellow stripe - Sames as # 15 and #16

I have looked through the ETM all night and can not find these guys. Also does anyone know if the C101 connection is pinned out in the ETM. I dont see it outlined on its own page?

Thanks for the help guys.

Michael

[Mike B.]

C101 Pin 20 (Red/Yellow) is for the braking system. Hint: check the ABS diagrams. :)

There is no direct correlation on the E36 harness for this pin, you will have to find a 12v source and run it to pin 20. I tapped a large gauge red/white wire from the Main Relay.