LSx E36 Wiring

[squashman702]

Bumping an old thread, but there's a bunch of good info in here, and I'd like to keep it all consolidated. Couple of questions . . . .

1. The PO stole the harness out of my 1997 E36M3 for his S52 swap in his E30. He took the three relays hanging from the side of the fuse box as part of it. My understanding is those power fuel pump, DME, and O2 sensors. I added a relay back in to the system in the trunk when I did an Aeromotive 340 pump, so I should be covered on one. The GM PCM powers the O2, correct? This should eliminate another one of these relays? All I should be left with is wiring one to the GM PCM? Where would this get added in?

2. The diagnostic plug for ABS (and BCM?) is also missing. Is this worth the hassle to pull this out of a junkyard to add back into the harness?

3. Since I'm working without a harness, I grabbed the three connectors (x20, etc) plus 20" or so of wiring from a junkyard to at least start on wiring. I'll go back and redo the connectors once I get the car running. Anything other major components I'm missing?

[TipsyMcStagger]

I'm a little confused as to what wire triggers the starter solenoid.

There's pin 15 and pin 18 on the x20. I currently have mine laid out to connect Pin 18 to the starter solenoid (purple wire). But what does pin 15 do? I've read some notes that it's just the BMW side wanting to know the motor is cranking and that it needs to be hooked up to the BIG terminal on the starter, is that correct? Doesn't the big terminal just have constant 12v?

I see some conflicting information, bimerok here mentions pin 15 being connected to the starter solenoid (purple wire): http://forums.bimmerforums.com/forum...8#post20005268.

I have 15 & 18 connected to the starter solenoid I believe, no issues/nothing has caught fire yet I think pin 15 triggers the unloader relay which shuts off all other things while the starter is cranking so that it receives maximum power. Pin 18 is the actual starter signal. Hope this helps.

I wired LSx to e36 chassis 3 times and always just used x20 pin 18 (Black/Yellow) for the starter. I never wired pin 15(Black/Green) to anything and unloader relay still works.

I believe on 96+ 328/M3 pin 15 does something for Body Control Module, but 3-4 years later, I haven't found what's not working So, I think I'm OK with my set up.

Any newly determined info or opinions regarding wiring X20 Pin 15? Yes...it's happening...I'm actually on the cusp of wiring Has anyone other than Sdobart connected X20-15 to the solenoid? And while I'm asking dumb questions, we are talking about connecting X20-15 to the same solenoid post as X20-18 (starter trigger), correct? So the solenoid wiring would be:

Post 1 - leave it as it is
Post 2 - connect to battery power
Post 3 - X20-18 and maybe also X20-15?





I'm probably going to make new battery cables to try to route things as neatly as I can. I know it's minor but does anyone know if the 90 degree starter lug with that little positioning "tang" can be sourced? 90 degree lugs are pretty easy to find but I'm wondering if there's a source for this OE type with the positioning tang.

Thanks!

Tipsy

[Pzary3233]

According to my spreadsheet (Wow this was about 7 years ago now), I did not wire up Pin 15 at all on my 99 M3 running a 0411 ECU. No ill effects.

[TipsyMcStagger]

According to my spreadsheet (Wow this was about 7 years ago now), I did not wire up Pin 15 at all on my 99 M3 running a 0411 ECU. No ill effects.

Okay...so that's Pzary3233 and Bimerok in the "didn't connect X20-15" camp. We have a majority

Good to see you back around here, Pzzary3233.

Tipsy

[Pzary3233]

Ha, I got an email from BF.c about this thread so I popped in, I have been thinking about doing an E46 swap....

[kt3130]

Any newly determined info or opinions regarding wiring X20 Pin 15? Yes...it's happening...I'm actually on the cusp of wiring Has anyone other than Sdobart connected X20-15 to the solenoid? And while I'm asking dumb questions, we are talking about connecting X20-15 to the same solenoid post as X20-18 (starter trigger), correct? So the solenoid wiring would be:

Post 1 - leave it as it is
Post 2 - connect to battery power
Post 3 - X20-18 and maybe also X20-15?





I'm probably going to make new battery cables to try to route things as neatly as I can. I know it's minor but does anyone know if the 90 degree starter lug with that little positioning "tang" can be sourced? 90 degree lugs are pretty easy to find but I'm wondering if there's a source for this OE type with the positioning tang.

Thanks!

Tipsy

Not to muddy the waters, but I just did this over the weekend. Here is what I observed in my situation (97 auto sedan to 2001 f body PCM, LS1/T56)

- with just x20-18 wired to post #3 the car would start just fine. However, if the car didn’t start, I had to turn the key all they way back to the off position before I could try to crank again. It wouldn’t allow me to go from run to start more than once. This got me thinking and combing the ETM and searching. It appears as if x20-15 comes from the EWS and registers when the starter is cranking? I thought maybe the EWS was cutting any further attempts since it wasn’t seeing any cranking happening?
- I then hooked up x20-15 to post #1, the logic being the EWS would see the starter solenoid energizing the starter. This workered exactly as it should. When the car wouldn’t start, or needed to be restarted, I could go directly from run to start without issue.

In summary, wire x20-18 to post #3, wire x20-15 to post #1 and wire the 12v constant to post #2. It’s not a game changer, but it made it function oem like for me.

[kenndoggy]

Not to muddy the waters, but I just did this over the weekend. Here is what I observed in my situation (97 auto sedan to 2001 f body PCM, LS1/T56)

- with just x20-18 wired to post #3 the car would start just fine. However, if the car didn’t start, I had to turn the key all they way back to the off position before I could try to crank again. It wouldn’t allow me to go from run to start more than once. This got me thinking and combing the ETM and searching. It appears as if x20-15 comes from the EWS and registers when the starter is cranking? I thought maybe the EWS was cutting any further attempts since it wasn’t seeing any cranking happening?
- I then hooked up x20-15 to post #1, the logic being the EWS would see the starter solenoid energizing the starter. This workered exactly as it should. When the car wouldn’t start, or needed to be restarted, I could go directly from run to start without issue.

In summary, wire x20-18 to post #3, wire x20-15 to post #1 and wire the 12v constant to post #2. It’s not a game changer, but it made it function oem like for me.

Thats normal, every BMW does that. It's so you can't engage the starter with the engine already running.

[TipsyMcStagger]

Not to muddy the waters, but I just did this over the weekend. Here is what I observed in my situation (97 auto sedan to 2001 f body PCM, LS1/T56)

- with just x20-18 wired to post #3 the car would start just fine. However, if the car didn’t start, I had to turn the key all they way back to the off position before I could try to crank again. It wouldn’t allow me to go from run to start more than once. This got me thinking and combing the ETM and searching. It appears as if x20-15 comes from the EWS and registers when the starter is cranking? I thought maybe the EWS was cutting any further attempts since it wasn’t seeing any cranking happening?
- I then hooked up x20-15 to post #1, the logic being the EWS would see the starter solenoid energizing the starter. This workered exactly as it should. When the car wouldn’t start, or needed to be restarted, I could go directly from run to start without issue.

In summary, wire x20-18 to post #3, wire x20-15 to post #1 and wire the 12v constant to post #2. It’s not a game changer, but it made it function oem like for me.

Very interesting. Thanks for posting!

Thats normal, every BMW does that. It's so you can't engage the starter with the engine already running.

Also interesting. Great info!

Tipsy

[bimerok]

Not to muddy the waters, but I just did this over the weekend. Here is what I observed in my situation (97 auto sedan to 2001 f body PCM, LS1/T56)

- with just x20-18 wired to post #3 the car would start just fine. However, if the car didn’t start, I had to turn the key all they way back to the off position before I could try to crank again. It wouldn’t allow me to go from run to start more than once. This got me thinking and combing the ETM and searching. It appears as if x20-15 comes from the EWS and registers when the starter is cranking? I thought maybe the EWS was cutting any further attempts since it wasn’t seeing any cranking happening?
- I then hooked up x20-15 to post #1, the logic being the EWS would see the starter solenoid energizing the starter. This workered exactly as it should. When the car wouldn’t start, or needed to be restarted, I could go directly from run to start without issue.

In summary, wire x20-18 to post #3, wire x20-15 to post #1 and wire the 12v constant to post #2. It’s not a game changer, but it made it function oem like for me.

Like kenndoggy stated, having to turn key off and then back on after you cranked the car once IS how BMW is working. If you can crank it again without having to "reset" then you altered standard operation of the ignition system.

The way you connected your starter wires is not correct and I would NOT recommend anyone following your steps.

Referencing the picture with numbers above: What is numbered on the starter can be though of as a relay, where #3 is a trigger wire, #2 is a VERY HIGH AMP Source wire and #1 is a VERY HIGH AMP Target wire, which is activated by the trigger #3. So when you apply voltage to #3 it jumps #2 to #1 to activate the starter motor. I would not recommend anything with such high AMP and the gauge of the wire touching the tiny (in comparison) wire in x20 connector.

You could accomplish the same thing that you did by just bridging together x20-18 and x20-15, but again, I don't see a reason for this and I personally would not recommend doing so to anyone...

[rabbatom]

Hey Pzary3233, I'm new to the forum and I'm attempting an e34 l33 swap. I'm not sure how the PCM would be integrated with the BMW harness, I was hoping the pdf's you provided would help me but they seem to be down. Would it be possible to share them again?

Thank You

[Pzary3233]

This was a LONG LONG time ago, let me look in my google docs....

[wbrentr]

I'm doing an ls3 swap in my 97 m3. I purchased a harness from wiring specialties (with obd2 port) which connects to X20. As I understand, X69 can be deleted and put in the fuse box. I;m still unsure what I am going to do with the X6031 connector. I have my old s52 harness, do I need to cut the X6031 connector off and wire to the body? I have been going through the manual and believe X6031 is used for traction control, emissions, and stability control?

[BigL350]

One thing in the x6031 connector you’re going to need is the CEL wire. You’re going to have to add a pin to the Wiring Specialties harness for that. The BMW under-hood diagnostic connector is something that you’ll probably want to figure out a way to keep so you can communicate with the ABS and airbag systems.


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[wbrentr]

I was under the assumption I didn't need to use my BMW DME. Now, I guess I need to keep it in the original location and use it for the ABS and Traction Control?

[TipsyMcStagger]

I was under the assumption I didn't need to use my BMW DME. Now, I guess I need to keep it in the original location and use it for the ABS and Traction Control?

You don't need the BMW DME. The ABS is controlled by a separate module. The traction control will no longer function with the swap.

[wbrentr]

Gotcha. So plug x69 and x6031 will be left empty?

[motorV8ed]

Bumping an old thread, but I haven't seen this discussed anywhere.

Essentially every swap-wiring source I have seen says that, for 99-02 F-body harnesses, one should be sure to apply fused 15A power to the pink wire in position C100G. This is referred to as "IGN 3" and/or "Engine Control Power" in the wiring guides on LS1tech and in the Cartech (SA) book "How to swap GM LS engines into almost anything" by Jefferson Bryant. LT1swap.com refers to C100G only as "Fused input feed." Near-universal advice seems to be to arrange a dedicated, relay-controlled feed to C100G.

Yesterday, I put my harness on a very mild wire diet. I removed the plugs/wires associated with EVAP vent, EVAP purge, secondary AIR, and EGR. I did not pull the harness completely apart, so I just was tracing and pulling the wires out of bundle. Eventually, this became too difficult without tearing it all apart, so I just snipped them off and taped the ends.

While trying to actually join the BMW and GM wires up today, imagine my horror when the pink C100G wire came out of the bundle with a snipped end! Further reading of wiring diagrams, etc., leads me to the conclusion that C100G only feeds the EVAP vent and purge solenoids, and the automatic transmission module. Soooo, if one is using a manual gearbox on an emissions-deleted car, C100G is not needed, I believe. Can anyone confirm or deny this?

13_evap.gif

[Pzary3233]

If it isn't going to the ECU, you don't need it... Which it is not, it's going TO the Evap.

C34 and C35 are the pins that control the evap system from the ECU those can be deleted along with the pink wires coming out of the other end of the evap stuff if not using emissions.

[motorV8ed]

Thank you! (Glad you are still subscribed to this thread! )

[bimerok]

Confirmed in my notes that C100 Terminal G is light pink wire going to purge control valve power. Notes next to it says DELETE and nothing was connected to it.

You are all good for that wire. However you do need terminal A from that connector on a 15A ingition switched fuse.

[Liquidity]

If it’s pink and goes to the PCM or a sensor, it goes to switched +12v. That’s all there is to know.

[motorV8ed]

Thanks, guys. I was pretty sure, but it's nice to have positive confirmation.

[Skrigz]

Anyone have the spreadsheets the links don't work anymore

[Pzary3233]

Yeah I killed hosting on that years ago let me see if I still have the Google docs folder. I should. Send me PM.

[motorV8ed]

Yeah I killed hosting on that years ago let me see if I still have the Google docs folder. I should. Send me PM.

I have a couple of pdfs saved (of the "Integration with...." files). I hope it is okay if I post them? (Unfortunately, I have to change the format from pdf to jpg to post here.)

Integration of LSx PCM Harness with OBD I e36 harness Blue PCM copy.jpg

Integration of LSx PCM Harness with OBD I e36 harness Red PCM copy.jpg