BoosterPlug -R1150RT

[roger 04 rt]

...

Re probe placement: R1150RT. Originally, I drilled a hole in my airbox and placed the BoosterPlug probe near the original BMW AIT probe. If I remember correctly, I still experienced surging especially after a hot-start. Right or wrong, I hypothesized that the air box was baking after shutting the engine down and the probe was trying to correct a temp that was much higher than ambient temp. I removed the probe, and placed a machine screw with some silicone on the threads into the air box hole.

Next, I placed the probe into the gap between the two air intakes. Much less surging upon hot starts. ...

This week, I disconnected my BoosterPlug. About 4500 miles since last tuneup. Bike exhaust was smelling of unburned hydrocarbons on cool mornings. Bike is stored in an unheated garage. ...

Assuming that your O2 sensor and AIT probe are in good operating condition, the surge on 1150s is caused by poor tuning. It took me about a year and a half to learn to tune mine. Roger's work is great and offers insight into the workings of the 1150 FI. But you must always remember that you have 2 cylinders and 1 O2 sensor that reads the exhaust after the exhaust pipes combine. So it basically reads an average. Then the FI uses this average reading to adjust the FI on BOTH cylinders, which changes the exhaust, which changes the average readings of the O2 sensor.....etc. The FI systems thinks your Beemer has one cylinder. It just injects fuel twice as often to both fuel injectors.

Both cylinders have to be matched nearly perfect for the system to work the way the FI was designed. Hit the sweet spot where the cylinders are balanced and the bike is awesome. Miss the sweet spot and the FI and O2 go nuts trying to figure out the correct fueling.

Correct tuning means good plugs, valve adjustment, throttle cable and throttle body balance. I use the Paul Glave's method of adjusting the TBs at about 2K RPMs.
1)Clean and balance TB big brass screws at idle. Then leave them alone.
2)Make sure you have the proper amount of slack in the left side throttle cable.
3)Then raise RPMs to 2K and adjust the right side throttle body using only the throttle cable. The cable will go out of adjustment when you tighten the lock nut. Play with it until you get the TBs to balance AS YOU TIGHTEN the lock nut.

You'll get an engine where both cylinders are putting out nearly equal amounts of energy. The BoosterPlug will richen the mixture just enough to SMOOTH the throttle response, rather than the ON-OFF throttle that came from the factory.

Thank you for the kind mention of my FI measurements. I'm in agreement with what you wrote, especially that an 1100/1150 should be fully mechanically tuned before considering other options. In addition, here are some things to think about.

1. You can mechanically tune for approximately equal air intake. However, fuel injector imbalance is neither measured nor can it be adjusted. If the FIs are unmatched, two things will happen:

a. During Closed Loop operation, one cylinder will be rich of stoic, the other on the lean side. The lean cylinder will experience a power change as the Motronic adds and removes fuel. On some bikes this will be felt enough to be called surging.

b. The rich cylinder will produce more power than the lean cylinder. This will be felt as vibration.

2. An old O2 sensor can become sluggish, leading to a richer overall mixture, a wider ramping of the afr during Closed Loop and a worsening of number 1 above. I don't know how to check the O2 for this condition. One might try disconnecting the O2 and seeing how the bike runs.

All other things tuned and operating properly, you can eliminate surge and add power:

A) For 1100s: Disconnect the O2 sensor, install the correct Cat plug but eliminate any ground to pin 86 or 87. Reset the Motronic. Add a CO potentiometer and tune it for best idle.

B) For 1100/1150: Disconnect the O2, install the correct Cat plug, reset the Motronic, add a BoosterPlug.

Or

C) Install a Wideband O2 system like an LC-1, program it to your preferred AFR in the 13.8 to 14.2 range, reset the Motronic.

[jammess]

Hi Roger,
Completed my mods to my '04RT. I disconnected the O2 sensor after doing the 0-0 adjustment to the TPS as described on ibmwr sight. This adjustment includes syncing the TBs using the throttle stop screws with both BBS set out equal amounts from the seated position. I turned both BBS out exactly one full turn from seated. Then installed a 10K pot in place of air temp thermistor. Long and short is I wound up setting the pot at 6K which produced a super smooth idle and very smooth around town riding at any RPM in first and second gear. The thermistor read 6.6K at a temperature of 25F so 6K is a bit warmer maybe 30F or slightly less. I like my results especially for the money spent which is maybe $5. Of course with your LC-1 with booster plug you also get good results and you have the advantage of knowing exactly what your AFR is whereas I only have a seat of the pants feel. Booster plug + LC-1 = $310 + shipping. Still not bad considering all that you have learned and it certainly has made for an interesting thread that has answered many of my questions so thanks. Oh, the TPS ended up with a voltage reading from the red/white wire to ground of .365 VDC.

[roger 04 rt]

...

All other things tuned and operating properly, you can eliminate surge and add power:

A) For 1100s: Disconnect the O2 sensor, install the correct Cat plug but eliminate any ground to pin 86 or 87. Reset the Motronic. Add a CO potentiometer and tune it for best idle.

B) For 1100/1150: Disconnect the O2, install the correct Cat plug, reset the Motronic, add a BoosterPlug.

Or

C) Install a Wideband O2 system like an LC-1, program it to your preferred AFR in the 13.8 to 14.2 range, reset the Motronic.

... Then installed a 10K pot in place of air temp thermistor. Long and short is I wound up setting the pot at 6K which produced a super smooth idle and very smooth around town riding at any RPM in first and second gear. ... I like my results especially for the money spent which is maybe $5. ... vs your Booster plug + LC-1 = $310 + shipping. ...

Very glad to hear that it worked out for you. It looks like my option B above but with a fixed one-riding-temp resistor--and the price was right.

Yes, I have the BoosterPlug and LC-1 but that's because I already owned the BP. The LC-1 is all that is needed because the Motronic does the work of adapting the open loop portion--$169 with gauge.

Comparing my option B to option C:

B gives AFRs of several percent below 14.7:1 but because the O2 is disconnected you disable the Motronic's adaptation functions.

C gives programmable control over closed loop AFR and leaves the Motronic fully functioning to adapt to fuel and wear--and works over the entire temperature range. But it does cost more than $5, but come to think of it, so does the motorcycle.

[happy wanderer]

All other things tuned and operating properly, you can eliminate surge and add power:

A) For 1100s: Disconnect the O2 sensor, install the correct Cat plug but eliminate any ground to pin 86 or 87. Reset the Motronic. Add a CO potentiometer and tune it for best idle.

I don't understand the point of Option A)
If you install the correct CCP which for a US model 1100 is the Yellow/Gold plug. It connects Pin 30 (Ground) to Pin 87 so it is grounding pin 87.
Then you say eliminate any ground So what was the point of installing the CCP? It only has one pin connected. To ground. I don't get it.

[roger 04 rt]

I don't understand the point of Option A)
If you install the correct CCP which for a US model 1100 is the Yellow/Gold plug. It connects Pin 30 (Ground) to Pin 87 so it is grounding pin 87.
Then you say eliminate any ground So what was the point of installing the CCP? It only has one pin connected. To ground. I don't get it.

Because some 1100s need 87a grounded. So I used the correct plug as the baseline.

[happy wanderer]

Because some 1100s need 87a grounded. So I used the correct plug as the baseline.

I'm missing something here.
Instruction 2 A) talks about leaving pin 86 and 87 un-grounded. But leave 87a grounded if you CCP has that connection to ground. So.. make a jumper from 87a to ground and remove the CCP no?
I am confused I think.. Anyway, it matters not. Most of the 1100s out there have the Yellow/Gold CCP which only has one connection. Pin 87 to ground. And most of them run a lot better when you just pull the CCP out.

[jammess]

Hi Roger,
Yes I guess by always staying in open loop the 2.4 motronic can't learn so it is kind of like the 2.2 motronic in my '94 1100 which is probably not a bad thing. Kind of reminds me of my brainless airhead '81 R100 which is definitely not a bad thing either.

Just went for a short ride on the '04 and I gotta say it is the best it has run since I bought it new, no question. Would be maybe kind of slick if I could find a single turn 10K water proof pot to mount between the speedometer and the tach, would be kind of like a choke, hmmmm. Never have seen a pot like that. Have to get out the Digi Key catalog.

Hi Happy Wanderer, Yup, pull out the yellow ccp or in my case open the back of the connector to the motronic and cut the jumper that grounds pin #87.

[keppelj]

"Just re-reading some earlier posts and wondering...

Did you pull Fuse number 5 to reset the ECU settings and do the throttle twist procedure to reset the TPS settings before you tested your Booster Plug ?"

Finally got back to this thread. Happywanderer, thanks for your wonderings. No, I did not perform the above. What's the throttle twist procedure? And pulling #5 fuse, in what relation to the ignition? Thanks....
__________________

[roger 04 rt]

... So.. make a jumper from 87a to ground and remove the CCP no?
...

That would do it. Pull the plug, if your bike needs 87a, jumper it, or however you like.

Hi Roger,
Yes I guess by always staying in open loop the 2.4 motronic can't learn so it is kind of like the 2.2 motronic in my '94 1100 ...

The Motronic 2.2 may not be as simple as is sometimes assumed. By 1994, design teams were considering individual UEGO Wideband sensors for individual cylinder AFR control and PID adaptation was the norm. Here is a note on Anton Largiader's site:

after a cold start (i.e. after reconnecting the battery), the Motronic puts some of its data to a static RAM which is not erased as long as fuse #5 and the battery are ok. After a warm start, a checksum is computed to see if the RAM contents are still valid.

So my working model at the moment is that the 2.2 has some amount of adaptation as well.

[GlobalRider]

I'm not having any issues with the way my oilhead runs. but I did read the Product Review in this months ON.

What gets me about any review is how they fail to include relevant info; in this case, some accurate fuel consumption numbers after the device was installed.

[happy wanderer]

"Just re-reading some earlier posts and wondering...

Did you pull Fuse number 5 to reset the ECU settings and do the throttle twist procedure to reset the TPS settings before you tested your Booster Plug ?"

Finally got back to this thread. Happywanderer, thanks for your wonderings. No, I did not perform the above. What's the throttle twist procedure? And pulling #5 fuse, in what relation to the ignition? Thanks....
__________________

Yes I did on the advice of a BMW mechanic however I remain unconvinced it made _any_ difference on my 1100 because it is equipped with the Motronic 2.2 ECU. You will not find a single mention of resetting this ECU anywhere in the factory manual.

The 1150 however is equipped with the Motronic 2.4 ECU, a different beast altogether. A quick look at the schematic will confirm that easily. And you will find mention of resetting the ECU in the factory manual for this bike and this ECU.

Whenever you change any of the inputs going to the 2.4 ECU it is advisable to reset it. This is done by removing Fuse number 5 in your fusebox for some time. Some say 10 to 16 seconds; I prefer to wait a good ten minutes to allow caps to discharge etc.

Then you reinsert the fuse and turn on the ignition. Do NOT start the bike. Twist the throttle slowly from the idle stop position all the way to full throttle and slowly back again. Do this THREE times, shut the ignition key off and then start the bike as you normally would and go ride it.

Remember that the 1150 takes some time to "learn" the new settings and supposedly adjusts things to suit the riders input like how aggressive you are or are not on the throttle etc.

I would be very surprised to learn that installing the booster plug makes no difference because it is fundamentally altering a major component of the input regime and "fooling" the ECU into believing it is 20 degrees C colder outside than it actually is which in turns enrichens the mixture and alters the way the bike behaves.

Roger04RT has plenty of proof of this in his thread on wideband O2 sensors here:
http://forums.bmwmoa.org/showthread.php?t=56990

[keppelj]

Happy Wanderer, thats for the clarification. For physical reasons I'm off riding for a bit, but will get back to it soon, I hope, and try your sequence. My RR isn't a serious surger, but it has been annoying. The worst of 4 oilheads I've owned.

[roger 04 rt]

Happy Wanderer, thats for the clarification. For physical reasons I'm off riding for a bit, but will get back to it soon, I hope, and try your sequence. My RR isn't a serious surger, but it has been annoying. The worst of 4 oilheads I've owned.

If your bike is reasonably tuned, one of these three options will most likely eliminate surging.

All other things tuned and operating properly, you can eliminate surge and add power:

A) For 1100s: Disconnect the O2 sensor, remove the cat code plug but ground 87a if your original cat cod plug did. Reset the Motronic. Add a CO potentiometer and tune it for best idle.

B) For 1100/1150: Disconnect the O2, install the correct Cat plug, reset the Motronic, add a BoosterPlug.

Or

C) Install a Wideband O2 system like an LC-1, program it to your preferred AFR in the 13.8 to 14.2 range, reset the Motronic

The effect of any of these is to slightly but predictably richen the mixture toward what is called Best Power where the engine is much less sensitive to fuel imbalances and changes (like when the Motronic is ramping fuel up and down to run the Closed Loop program).

BTW, I persuaded Jens at BoosterPlug to consign a loaner unit for 1100/1150 riders who want to try option B. It's been sent out on its first trial already.

P.S. HW, did you see that I fixed up the language of option A?

[happy wanderer]

If your bike is reasonably tuned, one of these three options will most likely eliminate surging.

All other things tuned and operating properly, you can eliminate surge and add power:

A) For 1100s: Disconnect the O2 sensor, remove the cat code plug but ground 87a if your original cat cod plug did. Reset the Motronic. Add a CO potentiometer and tune it for best idle.

B) For 1100/1150: Disconnect the O2, install the correct Cat plug, reset the Motronic, add a BoosterPlug.

Or

C) Install a Wideband O2 system like an LC-1, program it to your preferred AFR in the 13.8 to 14.2 range, reset the Motronic

The effect of any of these is to slightly but predictably richen the mixture toward what is called Best Power where the engine is much less sensitive to fuel imbalances and changes (like when the Motronic is ramping fuel up and down to run the Closed Loop program).

BTW, I persuaded Jens at BoosterPlug to consign a loaner unit for 1100/1150 riders who want to try option B. It's been sent out on its first trial already.

P.S. HW, did you see that I fixed up the language of option A?

I did notice that! Makes more sense to me now. I am easily confused though.

A really nice stainless SuperTrap muffler has fallen into my hands that will not accommodate an O2 sensor. As such, I plan to eliminate the O2 sensor and install a CO pot which is exactly how my last bike (96 RT) came from the factory. With a booster plug I did manage to eliminate most of the surging on the 96 model before I sold it and bought a 2000 model to replace it.

I have a couple more questions.
1- What do you think will happen if the O2 sensor is removed and no CO pot is installed? (I expect it would throw and error)
2- Do you happen to know what the value of that trimpot is? I'm trying to find some info on it (Value and pin numbers) but no luck so far!

When I had the 96RT I remember I removed the thing and documented it. Do you think I can find that stuff now?

[roger 04 rt]

...

I have a couple more questions.
1- What do you think will happen if the O2 sensor is removed and no CO pot is installed? (I expect it would throw and error)
2- Do you happen to know what the value of that trimpot is? I'm trying to find some info on it (Value and pin numbers) but no luck so far!

1) It might run too rich without the CO pot.

2) Red100RT (I think) put a 9 turn 1K pot in and adjusted for best idle. I don't know anything more about the value but if I come across it I'll let you know.