Bmw wiring

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timmy325is
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Bmw wiring

Post by timmy325is »

Hi everyone, I'm trying to get my 92 bmw 325is m50 turbo to start. I'm having trouble wiring the ms to correctly correspond to the cars wiring harness. Does anyone have any experience in this field. I do have the correct pinout.

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92 BMW 325Is M50 build, , MS3X v3.57 firmware 1.5, full sequential fuel and spark , LS2 Coils
grom_e30
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Re: Bmw wiring

Post by grom_e30 »

specifically what are you having issues with
1990 bmw 320i daily driver with m20b25 ms3 sequential fuel, 380cc injectors, d585 coil near plug, home made cam sync, launch control, fan control, vss, homebrew egt logging what's next????
93supercoupe
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Re: Bmw wiring

Post by 93supercoupe »

Ive got some expedience.

Whats a specific issue you are having?
BootlegTuned
timmy325is
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Re: Bmw wiring

Post by timmy325is »

I cant get the fuel pump relay to activate(checked cam position sensor and is good)The instrument panel- only the battery light comes on when I turn the key. There are some connections I'm unsure of
- Data Link connector
- check engine light
- fuel consumption
- o2 sensor relay wires- do I need to hook them up. I have wideband
- road speed
- on board computer
-diagnostic connector (rxd)
-diagnostic con. (Txd)
Evap. purge valve
Also which wire from the ms do I hook to the power supply with key on or engine running wire (green).
Maybe I'm over thinking it but I just don't want to fry anything
Thanks

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92 BMW 325Is M50 build, , MS3X v3.57 firmware 1.5, full sequential fuel and spark , LS2 Coils
grom_e30
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Re: Bmw wiring

Post by grom_e30 »

- Data Link connector not used by ms

- check engine light could connect to ms if using check engine light feature

- fuel consumption not used by ms obc and eco meter will be dead ( COULD SPOOTH SIGNAL OF GENERIC PWM)

- o2 sensor relay wires- do I need to hook them up. I have wideband depends if you are using stock o2 wiring to power your wideband

- road speed could wire to ms for vss related features

- on board computer ??? what wire to obc? fuel rate signal??

-diagnostic connector (rxd) not used by ms

-diagnostic con. (Txd) not used by ms

Evap. purge valve are you still running the carbon can or removing it?


Also which wire from the ms do I hook to the power supply with key on or engine running wire (green). do you have a dme relay??

Maybe I'm over thinking it but I just don't want to fry anything
1990 bmw 320i daily driver with m20b25 ms3 sequential fuel, 380cc injectors, d585 coil near plug, home made cam sync, launch control, fan control, vss, homebrew egt logging what's next????
timmy325is
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Re: Bmw wiring

Post by timmy325is »

Yes I'm using the stock dme relay

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grom_e30
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Re: Bmw wiring

Post by grom_e30 »

without having a wiring diagram i can only guess, but on my e30 the green is an ignition live that is meant to turn a transistor on inside the the stock ecu that then provides a ground to the dme relay turning that on, and that dme relay provides a clean 12v source to the injectors, icv, ecu and another electronics relating to the ecu. so i guess it will be something along those lines on your e36.
1990 bmw 320i daily driver with m20b25 ms3 sequential fuel, 380cc injectors, d585 coil near plug, home made cam sync, launch control, fan control, vss, homebrew egt logging what's next????
timmy325is
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Re: Bmw wiring

Post by timmy325is »

So which ms wire would work for that

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timmy325is
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Re: Bmw wiring

Post by timmy325is »

And yes the green wire on this e36 is the ign wire aswell. I'm just scratching my head at y the signal isn't getting thru. I can hear the dme relay click. But that's it no fp

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timmy325is
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Re: Bmw wiring

Post by timmy325is »

Any idea which parts of the v3.0 board is responsible for the fuel pump

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grom_e30
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Re: Bmw wiring

Post by grom_e30 »

q2 and q19 are the main bits, http://www.msextra.com/doc/pdf/html/MS3 ... 4-191.html

the megasquirt will supply a ground to turn on the fp relay


edit check you have 12v at the injectors and the icv. and on the red and white on the fuel pump relay
1990 bmw 320i daily driver with m20b25 ms3 sequential fuel, 380cc injectors, d585 coil near plug, home made cam sync, launch control, fan control, vss, homebrew egt logging what's next????
timmy325is
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Re: Bmw wiring

Post by timmy325is »

K I'll check

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timmy325is
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Re: Bmw wiring

Post by timmy325is »

I get no power

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grom_e30
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Re: Bmw wiring

Post by grom_e30 »

this will be as you are not turning on the dme relay so no power to the injectors, fuel pump relay, icv ect. should be a brown wire on pin 27 that needs a ground to turn on all that lot a transistor works great for this. you will get 12v on pin 54 red and white wire use that to power your megasquirt.

im assuming its a motronic 3.3 ecu stock
1990 bmw 320i daily driver with m20b25 ms3 sequential fuel, 380cc injectors, d585 coil near plug, home made cam sync, launch control, fan control, vss, homebrew egt logging what's next????
timmy325is
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Re: Bmw wiring

Post by timmy325is »

3.1 ecu I believe

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92 BMW 325Is M50 build, , MS3X v3.57 firmware 1.5, full sequential fuel and spark , LS2 Coils
timmy325is
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Re: Bmw wiring

Post by timmy325is »

So hook up a ground to the thin brown wire that's attached to the main relay?

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92 BMW 325Is M50 build, , MS3X v3.57 firmware 1.5, full sequential fuel and spark , LS2 Coils
grom_e30
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Re: Bmw wiring

Post by grom_e30 »

you will need to create a ground to that wire to turn it on. but this ground needs to be switched or the engine will stay running after you turn the key off. the best way is with a transistor, a resistor and a diode will also be needed for the circuit. i can supply further details if required.
1990 bmw 320i daily driver with m20b25 ms3 sequential fuel, 380cc injectors, d585 coil near plug, home made cam sync, launch control, fan control, vss, homebrew egt logging what's next????
timmy325is
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Re: Bmw wiring

Post by timmy325is »

Please do, and I appreciate your help tremendously.

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92 BMW 325Is M50 build, , MS3X v3.57 firmware 1.5, full sequential fuel and spark , LS2 Coils
timmy325is
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Re: Bmw wiring

Post by timmy325is »

Would 84 degrees sound about right for crank angle?

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92 BMW 325Is M50 build, , MS3X v3.57 firmware 1.5, full sequential fuel and spark , LS2 Coils
grom_e30
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Re: Bmw wiring

Post by grom_e30 »

you will want a 7.5k resistor, a 1n4001 diode and a 2n2222a transistor. the emitter of the transistor connects to ground there are loads of options at the harness, get you resistor and connect one side to the green ignition switch live on (pin 56). other end connects to the base of the transistor. the collector of the transistor connects to the brown wire on (pin 27). the diode wants the banded end connected to the red wire (pin 26) and the non banded end wants to connect to brown wire on (pin 27).

i think the m50 engine uses 84, but the m50 dual vanos and the m52 uses about 324. set the engine at tdc and count the gaps between the sensor and the missing tooth gap times the number of gaps by 6 to get your tooth# 1

edit: typo
1990 bmw 320i daily driver with m20b25 ms3 sequential fuel, 380cc injectors, d585 coil near plug, home made cam sync, launch control, fan control, vss, homebrew egt logging what's next????
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