2011 bmw e90 with a GM 5.3 LM7

95_Octane · Post by **95_Octane** » Wed Nov 16, 2022 3:37 pm

Hello guys I’m working on project that I’ll be using rusEFI to control, it’s a 2011 bmw e90 with a GM 5.3 LM7. This car will be a daily driver so AC will be a must have so I’m looking into how rusEFi would be able to control this. I’ve done some research and this is where I’m at.
Bmw e90 Ac on bottom switch status is sent out via canbus ive search on here and I’ve found the canbus data for that see picture below, so my question how can rusEFI use this data to control to control output pins on the ecu for ac compressor and fan?
What kinda of of signal would I be able to send on/off or pwm etc.
Did some research here and i came across Lua Scrip but I don’t understand it however I’m still trying to to get some help as to how I can get this to work.

Thanks.

Post by **AndreyB** » Wed Nov 16, 2022 4:00 pm

Just to confirm I get the picture right

You will have e90 body
GM engine with GM A/C compressor on it
and some rusEFI ECU? what rusEFI ECU?

First thing first - does e90 have a start button? Please post a photo of your current state.

I am hinting that first you need to have ECU turn on and off when you want it to turn on and off, also cranking.

Will help with A/C Lua bits in a bit.

95_Octane · Post by **95_Octane** » Wed Nov 16, 2022 5:10 pm

Yes e90 body
Gm engine with Gm ac compressor

Will be a custom ecu

Yes ac has a start bottom

95_Octane · Post by **95_Octane** » Wed Nov 16, 2022 5:14 pm

Actually for the Ac it has a Ac max and auto bottom

95_Octane · Post by **95_Octane** » Wed Nov 16, 2022 5:16 pm

What you mean photo of current state? Sorry I very little knowledge when it come to the programming side of things so I might not be familiar with certain terms

Post by **AndreyB** » Wed Nov 16, 2022 5:54 pm

95_Octane wrote: ↑
Wed Nov 16, 2022 5:16 pm
What you mean photo of current state? Sorry I very little knowledge when it come to the programming side of things so I might not be familiar with certain terms

I mean a picture showing where you are. A picture could be showing either a burned down e90 shell or it could be showing the state of your Proteus custom harness. I am trying to understand how far did you make it considering your focus on A/C before cranking

Post by **AndreyB** » Wed Nov 16, 2022 5:55 pm

95_Octane wrote: ↑
Wed Nov 16, 2022 5:10 pm
Yes ac has a start bottom

Start/stop button is often engaging starter, as in for the A/C to work we need to get the engine running?

95_Octane · Post by **95_Octane** » Wed Nov 16, 2022 6:23 pm

I haven’t gotten that far yet I’m just gathering everything but I want to know if I choose to got with rusefi I’ll be able to have my ac working I’m in Canada but this car will me driven mostly in the summer and I’ll need ac. Will be making a custom harness and ecu to fit the stock Dme box the bmw engine got messed up so the car is not drivable right now Gm engine is on the stand

95_Octane · Post by **95_Octane** » Wed Nov 16, 2022 6:24 pm

Start bottom and Ac controls

95_Octane · Post by **95_Octane** » Wed Nov 16, 2022 6:37 pm

From my research I’ve seen that rusefi does support GM 24x trigger which is what I have

95_Octane · Post by **95_Octane** » Wed Nov 16, 2022 6:41 pm

I’m waiting on pcb to start testing my plan is to fire up engine on stand and finalize Everything I’ll need for my harness once I get pcb

Post by **AndreyB** » Wed Nov 16, 2022 7:03 pm

I am 146% confident that A/C would not be a problem. It sounds like you do not need the full solution right now, just to check-mark it as not a problem.

What could be a problem is ECU power turn on/turn off. I am not 100% sure but E90 could be a modern enough platform where you need "wake-up on CAN" and "go to low power mode by CAN"

Current rusEFI hardware does not have it. Future alphax-8chan is being developed right now with that feature. Same with any other ECU you are considering.

Alternatively you would need to add a hard toggle switch for mechanical power on/off, that case it's much easier and you can daily drive a rusEFI same as a number of other vehicles are daily driven on rusEFI, some in hot climate where A/C is required.

95_Octane · Post by **95_Octane** » Wed Nov 16, 2022 7:53 pm

Trying to find the start circuit for my car

https://bmwteka.com/wds/ru/e90/0cee3ad7

95_Octane · Post by **95_Octane** » Wed Nov 16, 2022 7:59 pm

Looks like there should be a 12v key on somewhere

https://lse90.com/2020/10/19/lse90-com-swap-wiring-information/

Post by **AndreyB** » Wed Nov 16, 2022 8:12 pm

Perfect. With all this info I see no problems having rusEFI run the engine and give you A/C in summer

95_Octane · Post by **95_Octane** » Wed Nov 16, 2022 8:36 pm

Thank you very much for your time and patience sir I really appreciate I will continue moving forward with my project

it might be slow getting it going with the weather right now but I’ll give updates as I go along

rusefi.com