Resetting the BMS Unit (Motronic)
Joe #1065 & Stuportech
Note: This description is limited to a BMW 1st start procedure AFTER the battery has been disconnected (Negative terminal first !).
This description was taught to me by a BMW tech who performed 2 F.I. software upgrades. I watched him do it, then I did if myself at home as needed (when I bought a new battery, when I installed the Motolights, whenever I 100% disconnected power from the bike for 2-3 minutes).
Leave the battery installed, just disconnect the negative terminal 100% for 2-3 minutes. Note the clock will re-set to 12:00.
Pretend your bike has just gotten a FI software upgrade and the battery is disconnected.
Re-connect the battery positive 1st, put the plastic side panels on and roll the bike outside to fresh air.
Key on ignition to dash lights "on" position (DON'T START!).
Fully twist throttle 2 times hitting the min and max levels, release throttle completely.
Start bike with NO THROTTLE, leave bike alone (don't touch throttle) idling for 5-10 minutes until the fan comes on.
You are done. Ride away or shut down bike.
The next 30 miles further teach the ECU unit about you, the air temp, and the bike letting the bike find it's groove.
For the curious, try this same procedure WITHOUT the throttle 2-twist and fan-warm up steps and you'll notice a lazy bike with tired acceleration. I have done it both ways and swear by the full procedure.
I'm having the following problem. My bike starts instantly just with a bit a throttle. However, I have been having problems with keeping the engine running when I stop. This became increasingly so as the weather improved. So I decided to try a moditech reset to see if I could fix the problem. However, when I try to get the engine going after the moditech reset I still have to open the throttle a bit and if I let it go the engine stops.
Now, when I stop, the problem is still there. I've done the moditech reset twice as indicated here, but I see no improvement. I now find that it has become a very lazy bike... as ACTD has announced that happens if the throttle is only opened once during the procedure.
Any advice on how to get my bike back in form?
This isn't the place for the thread but it could be the battery connections (make sure the leads are tightly attached), the battery itself, or possibly the valves. I've listed the possibilities in order of likelihood.
Just tried this. It does not work.
The problem is that the bike does not start first time.
It needs around 10 attempts, and the throttle must be opened.
Any ideas on why it's struggling to start?
Yeah, it does need to start easily to do this.
Did this procedure and it made a BIG difference to my bike!!!
Just to confirm...
You only disconnect the negative and leave the positive cable connected throughout the procedure?
just disconnect the battery any way. you could also unplug the ecu.
Powered by mwForum 2.29.3 © 1999-2013 Markus Wichitill