bcm be-gone

Tuning The Delco In Realtime
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bcm be-gone

Postby sprattzvx » Fri Nov 18, 2011 9:29 pm

Now i have a realtime board, i am looking to disable the bcm, until the realtime adx and xdf files are available for vt vx.
Interestingly, having a quick play i was able to use ose plugin to connect both logging and emulation, but due to the xdl and adx issue, the data was no good. Since i was able to connect emulation without getting booted after first connecting the logging data stream, would this indicate that the bus chatter issue is no drama?
Finally, its been mentioned a few times that it is possible to disable bcm, but assuming simply unplugging it wont work, i would need to find the specific link between the bcm and pcm. So any one who has done this, where is the link? Or does the workshop manual wiring diagram go into enough detail to narrow it down. im willing to test new ideas associated to pissing of the bcm or xdls/adxs as long as theres minimal risk of hardware damage to the ecu.
Thanks people.
I know this wont help with the data issue but be good to work it out. Will use the flashtool for now.

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Re: bcm be-gone

Postby kojab » Sat Nov 19, 2011 7:30 am

The specific link between the bcm and pcm is at A3 on the pcm.

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Re: bcm be-gone

Postby sprattzvx » Sat Nov 19, 2011 2:35 pm

kojab wrote:The specific link between the bcm and pcm is at A3 on the pcm.

Thanks kojab.
engine module inputs/outputs. so a3 on a switch will allow the bcm to be powered up, but not communicate on the the bus? this is vy scv6 diagram. sorry so many questions, its a new learning process for me :study:
a3.jpg
a3.jpg (88 KiB) Viewed 7157 times

ha ha wordslinger pop and drop...honestly its the missus`s lappy :lol:

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Re: bcm be-gone

Postby antus » Mon Nov 21, 2011 3:44 pm

Is that the vehicle data bus in to the pcm, or is it only used for pcm<-->bcm. If its the vehicle data bus in to the pcm, then you'll need to install the switch on the BCM end. Sorry I cant be more help, my vehicle has just a plain old 808.
Have you read the FAQ? For lots of information and links to significant threads see here: viewtopic.php?f=7&t=1396

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Re: bcm be-gone

Postby sprattzvx » Mon Nov 21, 2011 6:35 pm

Antus thats what im wondering. Need to be sure a3 is just used by the bc to talk to pc through the bus and not used by the pcm to link for other bus comms to avoid disabling the bus altogether. So like you said, may need to switch the bcm end.
Google is not much help with relation to dta bus and comms technical info.
Playing with ose plugin was able to have succesfull logging and emulation with correct data.
Detected hardware and download cal successfull, so i closed the write junper on the nvram and reconnected again success. Changed idle to 1000 and hit upload.
I was all excited for a second there. All sweet until the progress bar was right near the finish, then i got booted and the car stalled. Is this bus chatter, or xdf related?
I wish i had 808 simplicity!

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Re: bcm be-gone

Postby sprattzvx » Fri Nov 25, 2011 10:07 pm

for any one interested in the details of doing this, here is what you need to do, cut the red highlited wire. it is a red/black wire on the bcm(not pcm), it has a yellow and green white wires next to it. wire a rocker switch or whatever you have inline. you can now real time tune using flashtool and nvram board. sweet.
you will have check engine and oil/p light on. to enable logging when using the ose plugin with the bcm switched off, you need to edit the adx connection macro and delete the listen for silence/heartbeat/chatter commands.
VT Commodore LOW SERIES BCM 1024x768.jpg
VT Commodore LOW SERIES BCM 1024x768.jpg (72.34 KiB) Viewed 7053 times


Data Wiring.png
Data Wiring.png (52.96 KiB) Viewed 7053 times


VY BCM-be-Gone mod
VY BCM and PCM Data Wiring.jpg
VY BCM and PCM Data Wiring.jpg (80.84 KiB) Viewed 4587 times


cheers all for the help :thumbup:
Last edited by sprattzvx on Sat Nov 26, 2011 1:37 pm, edited 2 times in total.

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Re: bcm be-gone

Postby antus » Sat Nov 26, 2011 7:42 am

Thanks for the follow up post, good info there!
Have you read the FAQ? For lots of information and links to significant threads see here: viewtopic.php?f=7&t=1396

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Re: bcm be-gone

Postby tris909 » Sat Dec 14, 2013 6:59 pm

sorry for bringing this post back to life, I have tried this wire switch mod on a vt series 2 v6 and I get no start, dead key. I have ensured several times I have the correct wire and plug and have tried with VATS disabled and still no go. in the end I have just unplugged the bcm at plug #2 top rh as you look at it under the steering column and all good for emulation etc. is this right? thanks

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Re: bcm be-gone

Postby VL400 » Sat Dec 14, 2013 10:51 pm

The plugin now supports detecting the heartbeat so should be able to leave the BCM connected... viewtopic.php?f=3&t=590&start=200#p35338

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