Cutting out

Not breaking out the champagne yet but that was a ride roughly 6 x as far as I have been before without a glitch, I have thought I had cured it before but that was after a few miles test ride not a long one like this.
Spent the last 30 miles doing all the things to try and provoke it, low RPM closing the throttle then slowly opening it again sitting in traffic etc.

Not even a stutter. and with all the really fine setting I have been doing to the throttle bodies/TPS it is running gorgeously now.

Found the short in the Lambda sensor wiring, must have been resting against the exhaust and the really hot day which started all of this was just too much for it, ever such a slight bit of damage to the insulation on two wires where they rest against each other, they don't touch all the time so that would cause the intermittent affect.

I have ordered a new Lambda sensor hopefully then all will be back to normal.

The gs911 is a superb device, straight away told me the error codes.

I have replaced some parts which I didn't need to;
Hall sensors I only replaced the sensors so they cost me about 20 UKP
Coil that was about 50 UKP

The following I don't consider a waste
HT leads, well it is always good to have spares I have had them go before on this thing.
Plugs are a service item
Throttle cables - they were looking frayed.
I have also ordered and am awaiting a ignition switch wire, but that seems to be only a matter of time until I need it anyway so I am doing that sooner rather than getting stuck.

Might put a couple of hundred on it tomorrow just to be sure.

Shez

Congratulations. I hope that solves all your problems. Can you be specific as to where you found the short and what you did? Was it under the tranny where the wires enter the sensor at the exhaust?

Also, do you have any information as to what is exactly happening when the wires shorted out? Was the Motronic shutting down the bike or was the 02 sensor sending overheating info to the Motronic?

Thanks, Greg

What I have done for now is simply unplug the sensor from the loom, I have ordered a replacement.
Close to where the sensor sits in the exhaust there was a kink, which was sitting against the Y piece. I suspect it was badly routed when the cat was removed.
It appeared to be shutting down the motronic momentarily until the short was removed then I could fire it up again, the rev counter and everything dived to 0 but the rest of the dash was fine. I was getting really bad on/off/on/off jerking sometimes when trying to accelerate which I can only put down to the wire moving back and forth.
If you think it could be the problem with yours just try unplugging the sensor from the loom and see if the problem goes away. As I understand it you can predict you be a specific distance from home?

Shez

Shez_ow01 said:

This is still happening and is driving me mad.
So far I have replaced;
...

Click to expand...

I didn't see BATTERY in the list of what you've replaced.

I had the same problem. The dealer tested my battery, and said it was on its last legs. I replaced the battery with a BRAND new BMW battery, and the problem WENT AWAY !!

So, the conclusion is, my 1999 R1100GS was suddenly switching off completely while I was riding it due to a bad battery. To re-start it, all I had to do was turn the key OFF, then start it as usual. Below a certain voltage, there seems to be a sensor that will kill the electrical system. A person at a BMW dealer said that some models have this "feature."

Hope this helps.
*

If he did replace the battery he may need to do it again, it's been 8 years since his last post.......