I have a question about the Booster Plug that I bought over the winter. So- hooked it up as per the instructions and began riding the bike this spring. Here in New England, spring is cold, so obviously that meant a bunch of sub-freezing mornings going to work and such. It's my impression that the bike is running rougher than before. Now, I know what the BP does, and I'm wondering if in these very cold conditions if it's causing the EFI computer to read too cold---is the BP something that benefits the motorcycle more if the ambient temperatures are more in the 70s or 80s or 90s, say.
What Boxer do you own? It's not in your profile. I live in MA and have run a BoosterPlug on very cold days. Initially my engine ran slightly better. After a while the Motronic learns to adapt the the slight richness caused by the shifted temperature sensor and your bike will run the same as before. As long as the air temperature is above 0 degrees F it should run fine. Below 0F your Motronic/BMSK may think the sensor is out of spec, which hightechcoonass reported.
Thanks Roger for the reply. I have a 2011 r1200gs. No- the coldest mornings that I have ridden to work the temperatures have probably been in the mid/upper 20s, so that sounds like that's not it. The difference in the way the bike ran seemed to be subtle, but maybe I was just imagining it after not riding for the past 5 months.
That doesn't make sense to me. Can someone explain that in more detail. The Boosterplug just makes the Motronic think the temp sensor is showing colder than it actually is. How can it adapt to that? How does it know that the temp sensor is not giving the true temp? If it can adjust richness if it thinks the temp sensor is giving a false signal, why does it need the temp sensor at all? Why doesn't it just run without a sensor from the factory and adjust richness on it's own? Electronics is mostly voodoo witchcraft to me, so if someone could explain this in laymen's terms
The Motronic or BMSK uses the oxygen sensor to measure whether the exhaust is richer or leaner than something called stoic, about an AFR of 14.7:1 for gasoline. About half of the operational fueling map runs at 14.7. So in that half of the map if the Motronic learns that it is running rich (could be due to many reasons) it cuts the amount of fuel. Then based on what it learns about fueling in the 14.7 area, it applies to the rest of the map. For example if the BoosterPlug creates a lower than actual temperature that results in a rich mixture by 6%, eventually the Motronic and O2 sensor see that for some reason it can meet 14.7 with 6% less fuel. It then makes a correction (called an adaptation) of 6% to all its fueling. This is a simplistic example but hopefully it gives the idea. It is best if the Motronic estimates the amount of fuel accurately and best if the adaptations are stable, meaning you don't want the Motronic to have to adapt to temperature as you drive down the road. So the Motronic uses four primary sensors to estimate the fuel needed: RPM, TPS, barometric pressure, and air temperature. That's why the intake air temp sensor is there. Early systems did not have a barometric pressure sensor and instead used Adaptatiion to adapt to slowly changing air pressure. That approach doesn't work well if you're riding in the mountains where air density can change rapidly. It is a sort of engineer's voodoo and not easy to explain. Further compounded by the fact that Bosch and BMW keep it secret and don't explain it.
I question the logic here of the system "knowing" that it is running too rich. It's a computer and it's making the fuel mixture decision based on the 4 data inputs you mentioned. If 3 of those inputs are unmodified, i.e. constant, and one input is modified (air temp), how does the computer "know" that it is being fed wrong data. Basic programming is that that the computer makes the fuel mix decision based on the data, there is no secondary system that validates that data. So it does not know what the "real" air temp is, only what the sensor tells it. If this bike has multiple sensor inputs to a computer chip that validates the data and then makes learned decisions based on it's perceived reality, then we are well beyond the technology that I thought existed today.
It is making it's decisions based on the five inputs I mentioned. That fifth input is the O2 sensor, which is what allows it to know that: a sensor has fed it the wrong data, or the fuel pressure is low, or the fuel potency (stoichiometricity) is different from pure gasoline (for instance E10 fuel), or there are leaks in the intake system, and more. The O2 sensor is what validates that data. The technology really isn't new and was developed by Bosch in the 70's and shipped since the early 80s. It is a necessity to make a catalytic converter function efficiently.
How long after removal of such a device will the bike run lean before it stabilizes back to normal? Can one just unhook the battery to reset it?
I have similar questions as I have noticed a tougher running engine. Installed bp in fall and was smooth running for a bit.
If you remove a BP it is a good idea to reset your Motronic. If you don't your bike will run 6% lean of stoic for a while.
Roger, a thought I had, since I am now currently ignoring my O2 sensor, would the booster plug be adapted out eventually? I know that we discussed there being less adaptation in this mode.
No, now if you add a BoosterPlug you will permanently add 6% to all fueling. Make sure to put the temperature probe where it will measure the intake air temperature accurately. If you do that you want to readjust your CO pot.
