Page 1 of 2 12 LastLast
Results 1 to 25 of 32

Thread: E30 Kill Switch help, please...

  1. #1
    Join Date
    May 2002
    Location
    Palm Harbor, FL
    Posts
    2,288
    My Cars
    M3, 318is, Z3 2.3, E30 325 (Spec E30) Isetta 300

    E30 Kill Switch help, please...

    I've looked through a ton of threads, and I just want to keep this easy.

    Want to mount a 6 terminal kill switch in the spot above below the passenger windshield. There is a power terminal block there - seems like the common place for a kill switch.

    I know my switch had 2 big lugs, and 4 small ones.
    I know the big ones and 1 set of small ones are open when the key is turned
    I know the other set of small ones are closed when the key is turned.
    I know when the car is running, and you pull the thick and thin wire off the positive battery cable, the car will continue to run (off the alternator).

    So, this is what I have so far...

    Disconnect both the thick and thin wire from the block under the hood.
    Connect the thick wire to the big lug on the switch
    Connect the thin wire to the small "open when the key is turned" lug
    Connect a 12" zero gauge wire from the other big lug to the block where the old thick wire was connected
    Connect a 12" ten gauge wire from the other small "open when the key is turned" lug to where the old thin wire was connected

    This will get me a switch that does not kill the engine, but will prevent the engine from starting (isolates the battery).

    So, the magic must be in those 2 lugs that are closed when the key is turned.

    What the heck do I attach to those 2 lugs?

    BTW - put all this detail in there, as I hope, with the answer, I can draw a schematic that will help at least E30 car builders - hopefully everyone.

    Thanks!
    Last edited by jblack; 08-13-2007 at 06:43 PM.
    EX-NASA SpecE30 Racer---NASA Florida Certified Instructor

  2. #2
    Join Date
    Feb 2003
    Location
    SF Bay Area, CA
    Posts
    4,119
    My Cars
    BMWs: 1; MINIs: 1

  3. #3
    Join Date
    May 2002
    Location
    Palm Harbor, FL
    Posts
    2,288
    My Cars
    M3, 318is, Z3 2.3, E30 325 (Spec E30) Isetta 300
    Josh,

    Thanks! I have seen that diagram, but it confuses me in a couple ways (by the way - that is exactly my switch):

    1. The wires that are labeled "Main Electrical Feed Circuit and Alternator" - Is that the thick wire that goes to the battery and the thin wire that goes to the battery, or is it the thick wire that goes to the battery with a "tap" off of it? If it is the former, how does the small wire make it back to the battery? If it is the latter, how do we interrupt the thinner wire's connection to the battery?

    2. The wire from the ignition switch to the ignition coil -which wire is that? Where is the best place to tap it?

    What I am hoping to do at the end is have a drawing just like that with E30 Specific colors and tap locations for everything. I hope it can be easily translated to other (E36/E46) applications.

    Thanks again.
    EX-NASA SpecE30 Racer---NASA Florida Certified Instructor

  4. #4
    Join Date
    May 2002
    Location
    Palm Harbor, FL
    Posts
    2,288
    My Cars
    M3, 318is, Z3 2.3, E30 325 (Spec E30) Isetta 300
    So - I updated the picture - help with the questions are appreciated....
    Attached Images Attached Images
    EX-NASA SpecE30 Racer---NASA Florida Certified Instructor

  5. #5
    Join Date
    Feb 2003
    Location
    SF Bay Area, CA
    Posts
    4,119
    My Cars
    BMWs: 1; MINIs: 1
    Quote Originally Posted by jblack View Post
    Josh,

    Thanks! I have seen that diagram, but it confuses me in a couple ways (by the way - that is exactly my switch):

    1. The wires that are labeled "Main Electrical Feed Circuit and Alternator" - Is that the thick wire that goes to the battery and the thin wire that goes to the battery, or is it the thick wire that goes to the battery with a "tap" off of it? If it is the former, how does the small wire make it back to the battery? If it is the latter, how do we interrupt the thinner wire's connection to the battery?

    2. The wire from the ignition switch to the ignition coil -which wire is that? Where is the best place to tap it?

    What I am hoping to do at the end is have a drawing just like that with E30 Specific colors and tap locations for everything. I hope it can be easily translated to other (E36/E46) applications.

    Thanks again.
    Well, I have a Z3, not an E30, so unfortunately I can only help with concepts, not with specifics.

    But the ONLY wire that goes to the battery should be the one on the left side of the diagram. The alternator and all other positive connections currently on the battery should go to the large pole on the right side of the switch.

    In other words, if your battery currently has two large wires on it (one to power the fuse box, and one to the alternator), then BOTH of those wires should be routed to the right side of the switch, and you should run a new wire between the left side of the switch and the battery.

    On the second question, I had a similar problem finding a suitable wire in my car. You just need to pick something that has connectivity when the car is supposed to be running, and should be interrupted when the car is supposed to not be running. It doesn't need to go to ground or power specifically, it just needs to be something that if you cut, the car won't run. On simple ignition systems on older cars, there's a single wire between the ignition switch and the coil, and that's the wire that you stick this switch in the middle of. You just have to find a similar wire.

    In my car, there's a wire that's powered by a relay controlled by the ECU that feeds all 6 coil packs. I stuck the switch in the middle of the ground side of the relay's control side. But an E30 will be different. If you can send me an electronic copy of an E30's wiring diagram, I'm sure I can find you a suitable wire.

  6. #6
    Join Date
    May 2002
    Location
    Palm Harbor, FL
    Posts
    2,288
    My Cars
    M3, 318is, Z3 2.3, E30 325 (Spec E30) Isetta 300
    Josh, that is a ton of help! I think (think) I understand the top part of the diagram. Please check it out - I'm pretty sure it is correct now.

    I have a Bentley Manual - I will take a look for that ignition to coil wire - but I feel I am getting closer (thanks to you on that).

    Next question - do you just ground the wire from the resistor to the switch, or is there another thing I'm missing there?

    Thanks!
    Attached Images Attached Images
    EX-NASA SpecE30 Racer---NASA Florida Certified Instructor

  7. #7
    Join Date
    Feb 2003
    Location
    SF Bay Area, CA
    Posts
    4,119
    My Cars
    BMWs: 1; MINIs: 1
    It's correct in that it'll work, but there's something I think you don't quite understand. The wire that goes to the resistor, and then to ground (yes, when they say negative, they mean chassis ground) is there to give the alternator someplace to output to when you turn the switch off.

    See, normally, power goes from the battery and/or alternator out to power the chassis. Think of the battery and alternator wires as power sources, and the "main circuit" as a power destination.

    The problem is that if you were to ignore the part of the circuit in the middle ("W or 1" on the diagram), then when you kill the main circuit, all of that power that the still-spinning (but slowing) alternator is producing will have nowhere to go, and that's tough on the alternator. So, when you turn the open the main part of the switch, that "W or 1" circuit actually closes. This routes the residual output of the alternator to the resistor and then ground, so that the alternator can drain safely.

    The bottom part of the switch ("Z or 2") opens and closes with the main part, as opposed to the opposite as "W or 1". The idea here is that when the main part of the switch is closed, power is flowing, and also, the signal wire to the engine circuitry is also connected. When you open the switch, you not only disconnect the battery, but you also shut off the car.

    So the top part is intended to isolate the battery. The middle part is intended to protect the alternator. And the bottom part actually shuts off the car.

    Make sense?

  8. #8
    Join Date
    May 2002
    Location
    Palm Harbor, FL
    Posts
    2,288
    My Cars
    M3, 318is, Z3 2.3, E30 325 (Spec E30) Isetta 300
    I think you got me there - there is some theory one needs to understand. I now get the three tiers of this - cutting power is only one (the top) step. You are saying you need to:

    1. Cut Power (tier 1) (open when the switch is turned)
    2. Give the residual power a place to go (tier 2) (closed when the switch is turned)
    3. Kill the process of the car running. (tier 3) (open when the switch is turned)

    This is why when you pull the battery (+) cable, the car continues to run, (missing tier 3) - but if you kill it with tier 1 and 3, you would really piss off the alternator - hence tier 2.

    Updated the picture - according to Bentley, Bk/YL goes from ignition switch to "Pull-in coil and Hold-in coil" - I will try to get a drawing posted up.

    Thanks again Josh!
    Attached Images Attached Images
    EX-NASA SpecE30 Racer---NASA Florida Certified Instructor

  9. #9
    Join Date
    May 2002
    Location
    Palm Harbor, FL
    Posts
    2,288
    My Cars
    M3, 318is, Z3 2.3, E30 325 (Spec E30) Isetta 300
    Attached is my redition of the wiring diagram for the later (89 and up) E30. As I mentioned, I think the wire to interrupt is the Black/Yellow wire on the right side. Correct?

    Thanks!
    Attached Images Attached Images
    EX-NASA SpecE30 Racer---NASA Florida Certified Instructor

  10. #10
    Join Date
    Feb 2003
    Location
    SF Bay Area, CA
    Posts
    4,119
    My Cars
    BMWs: 1; MINIs: 1
    Looks like black/yellow is the wire to the starter, not to the ignition. What are the other wires off of the ignition switch?

  11. #11
    Join Date
    Apr 2005
    Location
    Indianapolis
    Posts
    1,667
    My Cars
    scooter
    Quote Originally Posted by JoshS View Post
    Looks like black/yellow is the wire to the starter, not to the ignition. What are the other wires off of the ignition switch?
    Not sure about the E30, but on the E36 it's the green wire off the ignition switch that powers the ECU. Kill that power and the car won't run.

  12. #12
    Join Date
    May 2002
    Location
    Palm Harbor, FL
    Posts
    2,288
    My Cars
    M3, 318is, Z3 2.3, E30 325 (Spec E30) Isetta 300
    Quote Originally Posted by JoshS View Post
    What are the other wires off of the ignition switch?
    I agree that the black/yellow wire is starter (I saw coil, but I think that is in the relay for the starter)

    The only other info I have on the ignition is:
    Switch Position
    Ignition On or Start:
    --30 and 15 Continuity
    --30 and R Continuity
    Ignition On only:
    --30 and 15l Continuity
    Start only:
    --30 and 50 Continuity
    --C1 and C Continuity
    Attached Images Attached Images
    EX-NASA SpecE30 Racer---NASA Florida Certified Instructor

  13. #13
    Join Date
    Apr 2005
    Location
    Indianapolis
    Posts
    1,667
    My Cars
    scooter
    Quote Originally Posted by jblack View Post
    I agree that the black/yellow wire is starter (I saw coil, but I think that is in the relay for the starter)

    The only other info I have on the ignition is:
    Switch Position
    Ignition On or Start:
    --30 and 15 Continuity
    --30 and R Continuity
    Ignition On only:
    --30 and 15l Continuity
    Start only:
    --30 and 50 Continuity
    --C1 and C Continuity

    Where does the green wire go to in the wiring diagram?

  14. #14
    Join Date
    May 2002
    Location
    Palm Harbor, FL
    Posts
    2,288
    My Cars
    M3, 318is, Z3 2.3, E30 325 (Spec E30) Isetta 300
    New diagram. I added the following changes.

    A jumper from the large terminal to W/1 - I think this is OK, and will save trying to splice into the main battery cable. Is this OK?

    Changed the cut wire from the ignition from Black/Yellow to Green. I think that is correct, right?

    Added the Terminal Block that is in the E30 on the passenger firewall (it is also in Z3s, E36s and E46s - I confirmed). This is also the place where you would jump the car from the front end.

    Are we good with this?

    Thanks to all for the help!

    John
    Attached Images Attached Images
    EX-NASA SpecE30 Racer---NASA Florida Certified Instructor

  15. #15
    Join Date
    Feb 2003
    Location
    SF Bay Area, CA
    Posts
    4,119
    My Cars
    BMWs: 1; MINIs: 1
    Looks fine, as long as the battery powers nothing except for the switch. Are there any other connectors on that terminal block? Racing rules require the battery be completely isolated from all circuits, so as long as something else doesn't get power from that terminal block, it looks like you've got it.
    Last edited by JoshS; 08-14-2007 at 12:29 PM.

  16. #16
    Join Date
    May 2002
    Location
    Palm Harbor, FL
    Posts
    2,288
    My Cars
    M3, 318is, Z3 2.3, E30 325 (Spec E30) Isetta 300
    Quote Originally Posted by scottbm3 View Post
    Where does the green wire go to in the wiring diagram?
    To the alternator warning light in the instrument cluster, then it leaves as a blue wire to the alternator.... maybe the green wire is still not it....

    I know the brown wire leaving the switch at "C" and the Brown/Blue wire goes to the seatbelt warning system. This leaves:

    Violet from 15l
    Black/Yellow from 50
    Violet from "R"
    Red from 30

    According to the manual, "Terminal 30 brings power into the ignition switch from the battery. Terminal 15, terminal R and terminal 15l provide power to the ignition system and other parts of the electrical system (not real helpful) when the ignition key is in the ON position. Terminal 50 switches power to the starter. Terminal C and C1 are part of the seat belt warning system."

    So, we have 7 wires:

    C1 (NO - Seat Belt Warning) Brown/Blue
    30 (Don't think so - this is the power to the ignition from the battery) Red
    15l (?) Violet
    C (NO - Seat Belt Warning) Brown
    50 (NO - Starter) Black/Yellow
    R (?) Violet
    15 (I think this is the one) (Alternator) Green
    Last edited by jblack; 08-14-2007 at 01:12 PM.
    EX-NASA SpecE30 Racer---NASA Florida Certified Instructor

  17. #17
    Join Date
    May 2002
    Location
    Palm Harbor, FL
    Posts
    2,288
    My Cars
    M3, 318is, Z3 2.3, E30 325 (Spec E30) Isetta 300
    Quote Originally Posted by JoshS View Post
    Looks fine, as long as the battery powers nothing except for the switch. Are there any other connectors on that terminal block? Racing rules require the battery be completely isolated from all circuits, so as long as something else doesn't get power from that terminal block, it looks like you've got it.

    The battery powers nothing but the switch. There are other connectors at the block, but turning the switch would isolate the battery from the block completely.

    Thanks yet again!
    EX-NASA SpecE30 Racer---NASA Florida Certified Instructor

  18. #18
    Join Date
    Apr 2005
    Location
    Indianapolis
    Posts
    1,667
    My Cars
    scooter
    Quote Originally Posted by jblack View Post
    The battery powers nothing but the switch. There are other connectors at the block, but turning the switch would isolate the battery from the block completely.

    Thanks yet again!
    In your last diagram turning off the cut-off switch would not isolate wires going from the block to other relays and such as it's Post power. I would put the Cut-off between the battery and the block.

  19. #19
    Join Date
    May 2002
    Location
    Palm Harbor, FL
    Posts
    2,288
    My Cars
    M3, 318is, Z3 2.3, E30 325 (Spec E30) Isetta 300
    Scott - good catch - you are 100% on - updated accordingly. Also, one other Spec E30 racer suggested going right to the coil vs. the wire at the ignition. I put that option in too.

    Thanks all - I not only feel more comfortable with this from an installation and concept basis!
    Attached Images Attached Images
    EX-NASA SpecE30 Racer---NASA Florida Certified Instructor

  20. #20
    Join Date
    May 2007
    Location
    Mogadore, Ohio
    Posts
    1,220
    My Cars
    1993 Spec E36 Race car
    Hey John,
    Bring it to Road Atlanta and I will wire it for you. It will only take about an hour or so. Tim

  21. #21
    Join Date
    May 2007
    Location
    Mogadore, Ohio
    Posts
    1,220
    My Cars
    1993 Spec E36 Race car
    Teaches you not to move away!!!!!!!!!!!
    That is what you get. Can't you Floridians read.

  22. #22
    Join Date
    May 2002
    Location
    Palm Harbor, FL
    Posts
    2,288
    My Cars
    M3, 318is, Z3 2.3, E30 325 (Spec E30) Isetta 300
    What the hell do you know about electricity anyway...



    Hope to see you at RA! Get that door fixed!

    John
    EX-NASA SpecE30 Racer---NASA Florida Certified Instructor

  23. #23
    Join Date
    May 2002
    Location
    Palm Harbor, FL
    Posts
    2,288
    My Cars
    M3, 318is, Z3 2.3, E30 325 (Spec E30) Isetta 300
    So, after some help over at the Spec E30 pages, Bruce over there showed me the light on a better way to skin this cat. I unhooked the 2 battery cables (thick and thin) from the battery while the car was running, and the car continued to run- I assumed that this meant we had to find a different way to kill the engine.

    Wrong.

    If you disconnect the two wires, and separate them from each other - the engine dies. Success. I modified the drawing to accomplish this. I left in the part that protects the alternator (with the resistor to ground) - seems that most think the BMW alternator is tough enough not to need this - but there is a ground about 2 inches from where I'm mounting the switch, so what the heck.

    Thanks to all for the help - the education was worth the journey!
    Attached Images Attached Images
    EX-NASA SpecE30 Racer---NASA Florida Certified Instructor

  24. #24
    Join Date
    Aug 2004
    Location
    SIN CITY
    Posts
    1,796
    My Cars
    MANY TO LIST
    Nice, very nice. Good work. I just paid $50 to an electrician and he had it done for me, very professional work.
    I'll save that pic for future reference.
    Road racing addict.

    Juker008 don't send pm soliciting or advertising, against forum rules!!

  25. #25
    Join Date
    Feb 2003
    Location
    SF Bay Area, CA
    Posts
    4,119
    My Cars
    BMWs: 1; MINIs: 1
    Maybe I don't understand the diagram, but I don't see why that's going to kill the car. Is the alternator output (which will be a big 4ga or 2ga wire) still feeding the power distribution block? It can't ONLY go to the little pole of the kill switch. Where is the big fat alternator output wire going?

    If the alternator output is still connected to the "main circuit", and you don't do something to kill the ignition (as we were discussing before), nothing will stop the car.

    I'm theorizing that the engine stopped in your experiment because you disconnected the alternator and the battery from the "main circuit". But I'm not sure you're doing that in your diagram.

Page 1 of 2 12 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •