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Barrett_m3

BMWLINK CAN BUS

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Hello, so let me first say,  first time building a turbo car here, first standalone, and first time ever even hearing of CAN systems. I’ve done a decent amount of research, good amount of thread hunting here, but haven’t found the answer. 

Car is a 1995 bmw m3 s50b30 us spec. I have a plug and play g4+ ecu.  Car is obd1 so I’m not sure if it has a CAN system?

I have AEM x-series wideband, boost, and CAN guage, and I’m trying to tie the wideband and boost guage into the ecu CAN system, but The manual doesn’t show any CAN inputs. 

I’ve learned the “bus” theory, so would buying the CAN expansion harness and then tieing the gauges into the CAN +/- wires? Or do they need to go to inputs? I know the boost and wideband CAN wires are optional and don’t need to go to the ecu, so not the end of the world if I can’t integrate them with the ecu, but I’d really like to figure this CANBUS thing out.

I would like to use the AEMNET CAN guage to look at water temps and oil temps and pressure, but I do not know if my cars factory sensors will communicate with the CAN out of the ecu to the guage. 

I haven’t hooked the ecu up to power yet because I’m lost on wiring all of this stuff up. I hope I don’t sound COMPLETELY new, but like I said I’m new here.

Thank you for any help,

Barrett. 

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The E36 chassis does not have any factory CAN bus comms (at least from the engine ECU).  So that means you can use either of the two onboard CAN ports for aftermarket devices.  CAN is bi-directional so the same bus/port is used for both input and output. 

I dont see the point of connecting the boost gauge as that has its own sensor and the ECU already has a MAP sensor.  The wideband and AEMNet gauge can both be connected together to the same CAN port.

You will need a CANPCB cable and a CANF plug to connect your devices to the ECU.

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Okay this clears a lot up, thank you.

Since the car doesn’t have any CAN stuff originally would it be able to send the temp and pressure signals to the can guage? Is it all just in the  configuring?

Thank you again!

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8 hours ago, Barrett_m3 said:

Since the car doesn’t have any CAN stuff originally would it be able to send the temp and pressure signals to the can guage? Is it all just in the  configuring?

Yes, you can basically send any parameter/sensor that the ECU has connected, there are limitations on how many channels you can send but I would expect you will be able to cover all the stuff you want.   It will just be a matter of setting up the CAN,  I can give you a hand with that, once you are wired please attach a copy of your tune file and a note about what you want to send.

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Awesome! thanks a ton Adam, That was my main concern was about if signals had to be on CAN or if the ecu could send any (most basic) parameters to the can guage. 

 

Help configuring it would be amazing. I’ll post a file back here once I get these wires ran and some power to it.

thanks a bunch!

Barrett

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