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Old 11-27-2009, 06:48 PM   #156
jack splash
Two Sheds
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Joined: Jun 2004
Location: Pt Pleasant, NJ USA
Oddometer: 2,368
Test Idea.

Originally Posted by apullin
My 2007 always stalls when started from cold. Runs for about 20 seconds, then stalls. Also, sometimes while driving it around, the bike would start stalling and not run unless throttle was held at 20% open.
Battery recall did not fix problem.

Took it to the dealers again, they updated the firmware on the ECU. The bike still stalls when started from cold 50% of the time, although the stalling while warm seems to not occur any more. ECU showed no fault codes.

I have done a data log using my GS911 on the bike when it stalls upon starting from cold. The idle control valve pegs at 200 steps right when the bike stalls.

Since the ECU shows no fault codes, and the failure is intermittent, it'll be difficult to get the dealer to fix it on warranty; if they can't reproduce the problem, then I'd have to pay for diagnosis labour, hundreds of $$.

What are my options? I'm really frustrated by this problem, it's gone on way too long and taken too much of my time.
- I'm considering pulling out the ECU, desoldering the chips and reading out the firmware. Maybe I can disassemble the code and reprogram to fix it myself. I do have an SMT soldering station and 24 channel logic analyzer in lab.
- In light of the aforementioned voltage regulator problems, I might design a DC-DC converter board with a buck-boost converter, so proper running voltage will always be present.
- Pull out the whole BMW EFI system, rebuild with a Haltech or Megasquirt based system.
- If we can cast this as a safety problem, maybe we can organize a class action suit?
Hey: Used to be service manager at a MC dealship, Kaw, Suz,KTM, Maico. And now do Computer repair and network stuff.

Sometimes a failed part will pass all the tests recommended by the manufacturer, but still be bad. The only way to find out which part is bad, is to swap them out one by one.

For example: A Kaw nina900 would not start, the service manual had test for the various electronic ignition parts. Red to black wire = 10 ohms, blue to green = 15ohms etc. A unit would pass all the tests, but the bike still would not start. We replaced the CDI, whch passed the tests, with one from a bike in the showroom , and the bike started right up.

IMHO, try replacing the VR, CDI and see if it fix'es the problem. IMHO, this is the only way to fix an intermittant, stubborn problem. It requires at least another bike, (every part you need ) or a great dealer to do this.

Good Luck
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