bump starting and o2 sensors

[bacos]

For some reason, I have this recollection that, if you bump start a R1100S, you stand to screw up the oxygen sensor.

 

I also recall having had to do it some time back on my wife's S somewhere in Switzerland, and it didn't run right afterword.  (I resolved afterword to set up booster cables. Which I did, with her bike. But she isn't with me so I didn't bring any of the apparatus.)

 

Is my recollection correct or not? I'm stuck in France with a battery that appears to be dying, I have people to push start me to get to a motorcycle shop to get a new battery, but I don't want to hose up my O2 sensor in the process - I'd rather pursue... alternative solutions, if you will.

 

(there's enough voltage to run the pump, it's just that it's barely able to turn the motor. so, barring O2 sensor damage, a push start will be fine.)

[dirtrider]

1 minute ago, bacos said:

For some reason, I have this recollection that, if you bump start a R1100S, you stand to screw up the oxygen sensor.

 

I also recall having had to do it some time back on my wife's S somewhere in Switzerland, and it didn't run right afterword.  (I resolved afterword to set up booster cables. Which I did, with her bike. But she isn't with me so I didn't bring any of the apparatus.)

 

Is my recollection correct or not? I'm stuck in France with a battery that appears to be dying, I have people to push start me to get to a motorcycle shop to get a new battery, but I don't want to hose up my O2 sensor in the process - I'd rather pursue... alternative solutions, if you will.

 

(there's enough voltage to run the pump, it's just that it's barely able to turn the motor. so, barring O2 sensor damage, a push start will be fine.)

Afternoon bacos

 

No different than starting using the starter, it won't harm your o2 sensor.

 

Way back there there was some concern about push or pull  starting automobiles with catalytic converters, if they didn't fire right off there was concern that if pushed or pulled far enough it could flood the catalytic converter with raw fuel. 

 

I suppose that could happen with the BMW motorcycle but if it fires right off  when pushing then no harm or damage. 

[bacos]

Ah, got it. Now that I think about it, because it was just my wife and I and it was flat, so took a few tries to bump-start it (she is very strong but still only one person), so yeah there was probably a bunch of fuel that got through and toasted the O2 sensor. So the moral of the story is to wait for enough help. :)

[Hosstage]

Bacos, do you think part of the issue with the bike running poorly after the bump start could be due to the fact that the battery was low, or even bad, and that had more to do with the poor running than damaged O2 sensors? Plus, as mentioned, the extra fuel didn't help. I've not heard of those being affected by bump starting alone.

And did you make it to the shop for a new battery in France?

[dirtrider]

6 hours ago, bacos said:

Ah, got it. Now that I think about it, because it was just my wife and I and it was flat, so took a few tries to bump-start it (she is very strong but still only one person), so yeah there was probably a bunch of fuel that got through and toasted the O2 sensor. So the moral of the story is to wait for enough help. :)

Morning  bacos

 

Extra fuel should not have effected the o2 sensor, extra or excess fuel  can make the catalytic converter  get very hot once it fires off but the o2 sensor should be just fine. 

 

I'm not sure why that motorcycle ran poorly after the push start but if it was an 1100S or 1150 with a Ma 2.4 Motronic fueling computer then with a dead battery (or almost dead) it might have lost it's TPS learning therefore requiring a TPS re-learn & it probably lost it's learned fueling adaptives so that probably took some riding to re-learn the adaptives. 

 

If the o2 sensor actually went bad then it was probably due to something other than the push start. Unless the o2 sensor pigtail wire was not properly routed so was hanging down near the catalytic converter & became burnt when the cat converter lit off & became very hot due to excess fuel in it. 

 

I have push started & tow started a number of BMW 1100 & 1150 motorcycles & have never seen it damage the o2 sensor. It takes a slight downhill run to push start most 1100/1150 motorcycles with just one person, 2 good sized people can usually push start them on level ground but there needs to be enough battery power with the key-on to run the electronics & run the fuel pump so I usually remove the load relief relay to remove the headlight load before trying to push or pull start. 

 

I usually carry a narrow long strong tow strap as it much easier to pull start them with another motorcycle than start by pushing.   

 

I also carry some motorcycle sized jumper cables but due to difficult battery access on most 1100/1150 BMW's it is usually quicker & simpler to just pull start them.

Some in my riding groups are now carrying little 12v jumper power cells, those seem to work if they can get a connection to the battery posts or starter large B+ stud.