Swap with BCM

[87Skier]

Anyone completed a swap with the e38 ecm and BCM? I've been thinking about trying it out so I can get cruise and few other things.

I haven't found anyone online that has mentioned it being successful.

[Roaddogg]

I'm in the same situation. I've got a gen 4 with e38 and thinking about trying to integrate the BCM with it. Just debating whether it's worth the effort.

[Roaddogg]

What else would you use it for? I think it's needed for the alternator to work properly. Just wondering if there's any other uses for it.

[vannatta20]

Motech will soon have a bcm replacement. The module will let cruise, tap shift, park/neutral safery, reverse lights, and the ac coomand to all work. It will plug into the obdii port for the e38 ecu

[Roaddogg]

I'd be interested. But would really like options other than just plugging into obd2 port. Any way to hard wire it into system. Seems everyone wants to use obd2 so I'm going to have a stack of like 5 things hanging off it.

[vannatta20]

It can be hard wire by tapping into the wires on the backside of the obdii.

[87Skier]

Originally Posted by Roaddogg

What else would you use it for? I think it's needed for the alternator to work properly. Just wondering if there's any other uses for it.

It depends on which vehicle your engine came out of. Mine came out of a van, and the smart charging system is disabled. I think this can be disabled with an aftermarket tuner so that it puts out around 13.8 Volts all the time.

I plan to use cruise, tow/haul mode, and the brake pedal sensor. Right now, my engine ignores the brake input when it's running (I'm thinking this is how it was programmed) so when slowing down I get a pretty rough 2-1 downshift. Sort of looks like MoTech is doing the same. In their instructions they mention hooking up the brake signal.

As vannatta20 mentioned, you really don't need a BCM and some companies are working on their own. If you know what is being sent over the CAN bus, you can replicate the signal and send the same requests. If you are good you could buy a RaspberryPi or Arduino and make your own. I started this, but needed the BCM to know what was being sent.

Also, the BCM doesn't have any of the logic for cruise. The BCM takes the switch input and sends out a command to the ECM to "set speed." The same with decrease speed, increase or cancel.

I think the BCM also contains the windshield wiper relays. I was thinking about using this to drive intermittent wipers (my 72 only has low/high).

[Roaddogg]

I might try it if I can figure out enough things to hook up thru it to justify putting it in. I thought I found some threads on Google where they had used them but not a lot of info out there I could find either.

[Daaaanz67]

Following this one. Motech that’s interesting.

[Roaddogg]

Yeah I hope someone on here has done it already and can share their experience. Otherwise 87Skier your going to have to be our guinea pig haha. I'll probably try it but my project is in it's infancy and will be a while.

[87Skier]

Originally Posted by Roaddogg

Yeah I hope someone on here has done it already and can share their experience. Otherwise 87Skier your going to have to be our guinea pig haha. I'll probably try it but my project is in it's infancy and will be a while.

I've been talking to a guy on the HPTuners forum that used the BCM in his swap: https://forum.hptuners.com/showthrea...8-ECM-plus-BCM

He makes it sound like it works but has a few quirks.