Motronic AIT Sensor Modification

[Galactic Greyhound]

Just to throw another variable into this, I have reason to believe that the Motronic may actually vary the current through the ignition coil and so vary the spark energy and the combustion rate.

 

Thought you might like to know - hope I haven't screwed up any theories

[Kathy R]

 

Thought you might like to know - hope I haven't screwed up any theories

 

 

hyjack:

I feel like Helen Keller at the pump

/hyjack:

[roger 04 rt]

 

hyjack:

I feel like Helen Keller at the pump

/hyjack:

 

Hi Kathy, This is one of those things that's as simple or as hard as we're making it. The short version is there are a few ways to run our boxers with richer mixtures for those who'd like to try.

 

Just to throw another variable into this, I have reason to believe that the Motronic may actually vary the current through the ignition coil and so vary the spark energy and the combustion rate.

 

Thought you might like to know - hope I haven't screwed up any theories

 

GG, I've got a lot of data and I can tell you for sure that spark-timing and dwell angle are dynamic. No theories violated.

 

Hi DR,

Well, it seems to me that we are all kind of back at the beginning which is there are missing blocks of info concerning our motronics. Also, interesting thought about too much fuel on start up when spoofing AIT.

 

Roger,

Will stick to NTC. Hey, nice mpg. I have never come close to that (51 mpg) in 8 years riding my '04RT. Of course I seem to always be carrying a passenger and never ever ride in 6th gear and seldom ride below 70 mph so probably just riding style and 51 mpg on ethanol yet! When I could get regular non-ethanol my mpg always seemed better than on non-ethanol premium which is all I can get now as regular and mid grade is all ethanol.

 

 

I think the spark-timing thing is interesting but I've got lots of data on hand and will publish some more timing info on top of what's been published.

 

Here's the real test, "How's your R1100RSL running now that you've richened the mixture, any pinging?"

 

Something to keep in mind here when using a fixed resistor to spoof the Ma 2.4 system is that we don't know the IAT 's effect on spark timing.

 

According to info an engineering friend from Germany sent me a few years ago the Motronic Ma 2.4 is capable of sensor based ignition spark control trim. He was in the automotive side so his info was based solely on the automotive usage of the Ma 2.4. He could not find any information on (IF) the BMW motorcycle Ma 2.4 used temp (either engine or ambient air) to influence spark mapping trim.

 

Seeing as the BMW 1150 Ma 2.4 has a very dynamic spark advance (just put a T light on one & watch it dance) a guess on my part is there is good chance that both engine temp & air temp are some of the players in the overall Ma 2.4 spark trim.

 

The 1100 Ma 2.2 seems to have a more practicable spark advance curve but even on that I wouldn't completely rule out the possibility of some engine & air temp spark trim influence.

 

At least using an NTC for IAT spoofing keeps the actual intake temp & spoofed temp spread within a predictable range.

 

If looking for a cheap way to spoof the intake temp just grab another stock BMW IAT sensor from E-Bay (usually $15.00-$25), then drill a hole in the intake snorkel & fit a large rubber grommet that has a large enough hole for the IAT sensor to screw into.

Install the 2nd IAT sensor & wire in series with the original. You can check the sensor data posted above to get an idea of what double the OEM resistance will give you at any temp but usually will lower it somewhere in the 20°f to 25°f range in the normal riding temp range.

 

Then just add a shorting switch to shunt that added sensor so you can turn it off for very cold weather starting. A shunting switch should be added to any of the IAT spoofers as you really don't want to lower the 30°f & below "already plenty rich" cold starting mixture to be so rich you get cylinder wall washing & oil dilution on cold start.

 

Evening DR, Some good points and questions. I've actually got a ton of timing data. In order to start making sense of it, given the simple purpose of this thread, two questions for you to get us pointed in the right direction:

 

1) Running at some constant condition at 14.7:1, then I richen the mixture "magically" to 13.8:1. What do I need to do with timing, if anything? Or what opportunities present themselves with timing if I richen the mixture?

 

2) On a colder day, what does a spark-ignition engine do with its timing relative to a warmer day?

 

3) Spark-timing is the #1 reason I'm a fan of leaving the Coding Plug as designed by BMW.

 

For now, I've got hundreds of miles on 13.8:1 and other than it runs smoother, with more mid-band power, no hesitating, pinging or surging and with decent gas mileage. I comfortable continuing to run as I am

[Kathy R]

 

Hi Kathy, This is one of those things that's as simple or as hard as we're making it. The short version is there are a few ways to run our boxers with richer mixtures for those who'd like to try.

 

Thanks, Roger. Don't mind me. I don't even know how many miles I get (gasp) to the gallon. I'll sit here, reading, and try to learn something.

 

[JamesW]

Evening Roger,

My R1100RSL runs wonderfully and doesn't ping and for that matter my '04RT has never pinged either. Well, when the '04RT was new it pinged a bit until the rings seated and the oil consumption stopped.

 

The '93 RSL is just converted to a EURO version by the factory manual. No modes to AIT and none needed as it performs perfectly. The '04 is the one I have been working on by running open loop (O2 disconnected) and AIT modified with new NTC thermistors in series. This afternoon I re-connected the factory AIT to do a comparison with my home made booster plug and it didn't take long to decide my BP is a keeper. The idle is smoother and about 100 rpm higher than with the factory AIT. Power is up and noticeable in 5th gear roll on tests. I should also point out that part of modifying the '93 to EURO specs I am running it O2 disconnected to maintain open loop. Overall I'm pretty satisfied. I like riding the '93 the best because it is lighter, lower seat height, better handling and I like the forward lean angle as it relieves pressure on my lower back. Just a more comfortable, for me, ride than the RT. I have never ridden an RS and I am really sold. If I part with one of my beemers it will be the RT mainly for ergonomic reasons. Sorry for wondering off topic, I'll behave.

[steelerider]

Or......if you want a richer mixture in open and closed loop mode you could install a Techlusion 1332ST. I have one, its a 20 min install and the bike runs great.

[roger 04 rt]

Looks like I'm going to hijack myself ...

 

 

I know people get results from the Techlusion but I believe it disables Closed Loop and makes its correction to Open Loop fueling only. And the enrichment is an unknown amount. Still, I agree it is an option.

 

Even though it has an O2 connector, here is the only documentation I can find on why the O2 connector is there. The following dialog comes from their support forum, if there is other documentation on its operation I would like to read it.

 

Dialog

flhtcrp 06:22 PM Aug 23rd, 2010

 

Is there a TFI I can use that don"t elimiate the 02 sensors? 2009 FLHTC

 

Hoople 06:35 PM Aug 23rd, 2010

The o2 sensors is what makes the A/F ratio run lean. (14.3-14.7) You have to bypass them in order to run outside of that window.

 

But if you left the o2 sensors working, they would see that extra richness and would tell the ECM to lean out. There would be a big tug of war going on.

 

You really need to disable them which will force the ecm to go by "look up tables" only,, and then "stack" some extra pulse width on top of the look up table value using the TFI.

Hoople 08:43 AM Aug 24th, 2010

Did not see this was official Support area. Please delete my replies.

 

 

DobeckTechSupport 11:12 AM Aug 24th, 2010

Great answers Hopple and you are absolutely correct.

 

If you did not want to bypass the O2 sensors then you would just have to turn the GREEN pot to 1:00 which is OFF. What you would lose though is the down low horsepower and torque most people are trying to gain. Without turning the GREEN pot off you would end up in the "tug of war" which Hopple mentioned. This causes horrible drivability and could lead to throwing engine lights.

 

[TestPilot]

Or......if you want a richer mixture in open and closed loop mode you could install a Techlusion 1332ST. I have one, its a 20 min install and the bike runs great.

 

As I read the Techlusion instructions, it doesn't alter closed loop fueling. It does let the user select where closed loop fueling is enabled, based on injector pulse width.

[roger 04 rt]

Or......if you want a richer mixture in open and closed loop mode you could install a Techlusion 1332ST. I have one, its a 20 min install and the bike runs great.

 

As I read the Techlusion instructions, it doesn't alter closed loop fueling. It does let the user select where closed loop fueling is enabled, based on injector pulse width.

 

Hi TP, I haven't seen that documentation. Sounds like they're looking for it to stay enabled around idle, for compliance?

 

I guess this is it. Perhaps it holds off Closed Loop until higher RPMS?

CRUISE FUEL POT- Adjusts fuel at cruise and light acceleration in closed loop mode. This pot should be set at 9:00 (4v) to

start tuning. The green fuel LED should be lit, if not then turn the cruise pot down (ccw) just enough to turn on the green fuel

LED. There should be little or no surging below 55 mph at this setting. Decrease the pot setting in one clock position increments

until you notice a deterioration in cruise performance. Increase the pot setting in very small increments until the cruise

performance is just restored. This setting will yield the best gas mileage.

 

Interesting too that their documentation calls for the correct Coding Plug to be installed. I'm a fan of that too.

[TestPilot]

Here's a link to the instructions for the Techlusion FI-1332ST: Link.

 

Page 3, paragraphs 4d and e briefly describe modes 4 and 5, which define the lower and upper injector pulse width limits within which closed loop fueling is possible. Page 5 contains the instructions for tuning each of the modes.

[roger 04 rt]

Karl,

 

Thank you, very helpful.

 

I think their design is clever. It has to learn RPM from the pulse train (except it looses that during overrun fuel cutoff and it must take a bit to recapture the rate) and "load" from fuel injector pulse width.

 

Then, at least the 1332ST, it can either be in Closed Loop without richening (no enhancement) or in three areas where it blocks Closed Loop (idle, acceleration, and high RPM). I see no reason why it can't do what it says.

 

With the Closed Loop on during cruise, many bikes still might surge. And since TPS opening initially leans the mixture, and the 1332ST doesn't monitor the TPS, they begin enriching acceleration after the RPM starts to pickup--a little late ideally. (By comparison, if you start with a richer mixture in cruise, there is some excess fuel as soon as you turn the throttle.)

 

Maybe if you get its Closed Loop range set just right you can avoid the surge area. And it is a quick, easy, plug and play install. I really wish they would be more specific about what the ranges of Closed Loop operation are, and more specific about how much fuel it adds--but that's me.

[legarem]

Yesterday, was THE day to try my bike with the modifications done on my twin spark 2003 RT. Temperature was 16 C

 

NGK iridiums

O2 sensor disconnected

2.2K resistor added in series with the air temperature sensor

 

As specified, my bike didn't have any surging

 

If i have only one word to describe what these mods do I would say: FUN

 

The bike is a lot more funny to ride. I can now feel the torque of this motor and it revs a lot faster and better when opening the throttle at low and high speed. I will NEVER return with this bike in stock condition.

 

The 2,2K resistor will be replaced by another BMW IAT sensor we can buy for 20$ on eBay. I will connect it in series with the one on the bike. I figured that the Motronic should see near -20 C at all temperatures with this added sensor. This should end the mods done unless I will have another stick coil problem later. If one of them fails, I will replace them with standard coils with spark plug wires.

[japachap]

Yesterday, was THE day to try my bike with the modifications done on my twin spark 2003 RT. Temperature was 16 C

 

NGK iridiums

O2 sensor disconnected

2.2K resistor added in series with the air temperature sensor

 

As specified, my bike didn't have any surging

 

If i have only one word to describe what these mods do I would say: FUN

 

The bike is a lot more funny to ride. I can now feel the torque of this motor and it revs a lot faster and better when opening the throttle at low and high speed. I will NEVER return with this bike in stock condition.

 

The 2,2K resistor will be replaced by another BMW IAT sensor we can buy for 20$ on eBay. I will connect it in series with the one on the bike. I figured that the Motronic should see near -20 C at all temperatures with this added sensor. This should end the mods done unless I will have another stick coil problem later. If one of them fails, I will replace them with standard coils with spark plug wires.

 

Yup- Im running NGK Iridiums too (with the tiny centre electrode), 1000ohm-in-series IAT resistor, but with the pink CCP and O2 still connected.

I like my set-up, but may try without the O2 next time the fairing is off...

[roger 04 rt]

Yesterday, was THE day to try my bike with the modifications done on my twin spark 2003 RT. Temperature was 16 C

 

NGK iridiums

O2 sensor disconnected

2.2K resistor added in series with the air temperature sensor

 

As specified, my bike didn't have any surging

 

If i have only one word to describe what these mods do I would say: FUN

 

The bike is a lot more funny to ride. I can now feel the torque of this motor and it revs a lot faster and better when opening the throttle at low and high speed. I will NEVER return with this bike in stock condition.

 

The 2,2K resistor will be replaced by another BMW IAT sensor we can buy for 20$ on eBay. I will connect it in series with the one on the bike. I figured that the Motronic should see near -20 C at all temperatures with this added sensor. This should end the mods done unless I will have another stick coil problem later. If one of them fails, I will replace them with standard coils with spark plug wires.

 

Congratulations and thanks for letting us know. I second your FUN comment. The power really comes on nicely with a little richer mixture. I agree that two sensors in series should give you what you want-- about 20C or about 6% richer.

[roger 04 rt]

I bought a second IAT sensor and received it last week to replace the 2.2K resistor i placed in series with the IAT on the bike. Now there's two IAT sensors in series to simulate the Booster plug. When replacing the resistor for the second IAT sensor I discovered that the 2.2 K resistor was bad. It was open. I was riding the bike without any IAT sensor. I loved my bike with the bad (open) resistor and O2 sensor disconnected. The low end grunt was there like I loved.

I had the torque feeling of old air head BMW motors.

 

Yesterday when placing the second IAT sensor in series with the one on the bike, I made a Motronic reset and made a ride, Now, it seems that the low end torque I loved so much disappeared, Acceleration is good but the torque feeling I loved so much is gone.

 

Without any IAT sensor and O2 disconnected, what is the air/fuel ratio I had with this bike ?

 

Now the bike has better idle but I miss what I loved previously without any IAT sensor.

 

My bike is a R1150RT twin spark which didn't have any surging problems.

 

If the bike is cold could you measure today's temp and the total resistance of the two sensors just as a check?

 

When I've pulled the AIT, my GS-911 reports 20C from the Motronic so I guess that is where the fuel tables are set. That doesn't seem like it would get you to the richer mixture.

 

However, if some Adaptation Values had been stored, then the resistor broke, then the temperatures warmed as they have since you started this, perhaps there were some richer, cold adaptive values. That's the only thing I can think of. (Although I believe you are Open Loop now with the O2 disconnected?)

 

That might mean when your resistor broke, it stayed with Cold Factors. I have a graph of something like that which I'm going to post in the O2 thread later.

[roger 04 rt]

I bought a second IAT sensor and received it last week to replace the 2.2K resistor i placed in series with the IAT on the bike. Now there's two IAT sensors in series to simulate the Booster plug. When replacing the resistor for the second IAT sensor I discovered that the 2.2 K resistor was bad. It was open. I was riding the bike without any IAT sensor. I loved my bike with the bad (open) resistor and O2 sensor disconnected. The low end grunt was there like I loved.

I had the torque feeling of old air head BMW motors.

 

Yesterday when placing the second IAT sensor in series with the one on the bike, I made a Motronic reset and made a ride, Now, it seems that the low end torque I loved so much disappeared, Acceleration is good but the torque feeling I loved so much is gone.

 

Without any IAT sensor and O2 disconnected, what is the air/fuel ratio I had with this bike ?

 

Now the bike has better idle but I miss what I loved previously without any IAT sensor.

 

My bike is a R1150RT twin spark which didn't have any surging problems.

 

If the bike is cold could you measure today's temp and the total resistance of the two sensors just as a check?

 

When I've pulled the AIT, my GS-911 reports 20C from the Motronic so I guess that is where the fuel tables are set. That doesn't seem like it would get you to the richer mixture.

 

However, if some Adaptation Values had been stored, then the resistor broke, then the temperatures warmed as they have since you started this, perhaps there were some richer, cold adaptive values. That's the only thing I can think of. (Although I believe you are Open Loop now with the O2 disconnected?)

 

That might mean when your resistor broke, it stayed with Cold Factors. I have a graph of something like that which I'm going to post in the O2 thread later.

 

AndI meant to add that the adaptations got erased when you recently reset.

[legarem]

Today the temperature is near 20C The two IAT in series gives 4900 ohms.

 

I strongly suspect that the bad resistor didn't went bad but was bad before I used it.

[roger 04 rt]

Today the temperature is near 20C The two IAT in series gives 4900 ohms.

 

I strongly suspect that the bad resistor didn't went bad but was bad before I used it.

 

I know the motronic reads back 20C with an open sensor. When I get a chance this week I will pull my sensor, reset the motronic and take a test ride.

 

As you know the 4.9K is a good value for 0C. I'll let you know what I find when I take the test ride.

 

Does your fuel have alcohol and is your O2 connected?

[legarem]

There's no alcohol in the gas and the O2 sensor is disconnected.

 

After dinner, I disconnected the AIT sensors and reseted the Motronic. I'm just returning from a 80 km ride and my smile is back when I drive the bike. There's a HUGE difference between something like Booster Plug and no IAT or resistor at all connected. When coasting at 80km/h, in 6 th gear you open the throttle and don't have to downshift to go to 120 km/h. The bike also 'feels' throaty at acceleration. with this setting, this twin cylinder really feels like a twin should feel. A word: Torquey.

 

I'll look later at the MPG I'll do with the O2 and IAT disconnected.

 

I would be happy if someone try it because it makes the 1150 a different animal.

 

Now I would like to know what air/fuel ratio i'm running when the O2 and IAT are disconnected.

 

I also would like to know the Motronic reaction when there's no IAT connected. For sure it don't work like it is setting the parameters for 20C

[roger 04 rt]

There's no alcohol in the gas and the O2 sensor is disconnected.

 

After dinner, I disconnected the AIT sensors and reseted the Motronic. I'm just returning from a 80 km ride and my smile is back when I drive the bike. There's a HUGE difference between something like Booster Plug and no IAT or resistor at all connected. When coasting at 80km/h, in 6 th gear you open the throttle and don't have to downshift to go to 120 km/h. The bike also 'feels' throaty at acceleration. with this setting, this twin cylinder really feels like a twin should feel. A word: Torquey.

 

I'll look later at the MPG I'll do with the O2 and IAT disconnected.

 

I would be happy if someone try it because it makes the 1150 a different animal.

 

Now I would like to know what air/fuel ratio i'm running when the O2 and IAT are disconnected.

 

I also would like to know the Motronic reaction when there's no IAT connected. For sure it don't work like it is setting the parameters for 20C

 

Very interesting! I know that the Motronic reports 20C to the GS-911. And you know that "no AIT" runs strong. It sounds like your bike is running like mine does at 13.5-13.8. When I get time this week I will pull the O2 and AIT and data log a plot of afr.

 

Looks like ait "limp home" might be rich enough for a cold day. That would still mean afr would vary with temp.

[roger 04 rt]

 

Since I won't get to make a test for a couple days, I've thought about what the Motronic might do with no IAT sensor. It now seems to me that it must make the mixture rich enough for a cold day. Say -20C. That could make the mixture 12-15% rich at 20C maybe more.

 

No O2 and an extra IAT sensor gets you 6%. But without closed loop the range is like 13.8 to 14.7 check my graphs in the O2 thread. With no IAT sensor I bet I find that range is 13-14:1 on a 20C day. Probably too rich but certainly in the Best Power Mixture range.

 

On a 0C day, you'd be back to only 6% and with the spread that my chart shows and on a 35C day you probably will have a 20% boost.

 

With an LC-1 you can pick the mixture accurately and it holds for every temperature.

 

But I will make a no IAT test run like I said

[legarem]

The oil temperature sensor probably cancel the AIT sensor until the motor is warm. When the motor is warm (4 bars ?) the AIT makes it's job to lean the air/fuel. Like you wrote, no AIT sensor means that the motor fuel /air ratio stays rich like it was always cold. I'll wait for your results and I will look at the fuel consumption like it is. The results are simply amazing with no AIT sensor.

[legarem]

Roger

 

Remember I wrote that my bike had more bad smelling exhaust gas. Now you and I know why.

[roger 04 rt]

The oil temperature sensor probably cancel the AIT sensor until the motor is warm. When the motor is warm (4 bars ?) the AIT makes it's job to lean the air/fuel. Like you wrote, no AIT sensor means that the motor fuel /air ratio stays rich like it was always cold. I'll wait for your results and I will look at the fuel consumption like it is. The results are simply amazing with no AIT sensor.

 

I'd like to add that the results at 13.5 - 13.8 are simply amazing. If you haven't ridden a boxer with a 6 - 8% richer mixture in the mid-13s, it's hard to be convincing about how different it is.

 

If you look at the various AFR curves I've published, you can usually see the warm-up enrichement dropping to zero meaning starting in the low 13s and headed to high 14s before closed loop kicks in. I'm guessing, now, in the broken IAT sensor scenario that even during warm-up it's richer than usual since the IAT is an add-on multiplier.

 

To your other point, I think we can agree the reason you were smelling fuel. Even at 13.5, there is no excess fuel smell that I can detect so your no-IAT must be very rich. You don't have to get the AFR into the 12s to feel a really powerful bike, mid-13s seems to do it.

 

The reason mid 13s is good is that you only have to get the mixture rich enough so that all the O2 has been consumed. Once you're there, that's Best Power mixture. After that point of richness, there's no more HP/Torque gain.

 

Here's my take, based on the tests:

 

14.7:1 -- Most bikes run fine with tuning but have some amount of incomplete combustion. Whether you notice it or not depends on you (the rider) and the individual characteristics of your bike.

 

14.0 to 14.3:1 -- The bike runs without any hesitation, rough spots or surging. Not yet at its maximum power potential

 

13.5 to 13.8 -- Near Best Power mixture, burning all the O2, creating the most HP and torque. Fuel use is increase by 50% of the amount of enrichment. Enrich by 6% get 3% more power and 3% more fuel use (but sometimes run a lower gear and save fuel).

 

<12.8:1 -- Probably more fuel than needed. I haven't run this low yet.

 

RB

[roger 04 rt]

The oil temperature sensor probably cancel the AIT sensor until the motor is warm. When the motor is warm (4 bars ?) the AIT makes it's job to lean the air/fuel. Like you wrote, no AIT sensor means that the motor fuel /air ratio stays rich like it was always cold. I'll wait for your results and I will look at the fuel consumption like it is. The results are simply amazing with no AIT sensor.

 

The rain held off here this morning and I made a test run. The Motronic was reset, the AIT fully disconnected (GS-911 reported it as OPEN), the O2 was disconnected (unsoldered inside my junction box). The test ride was about 10 miles with a full AFR log taken. The temperature was 21C when I made the test run. My bike is a 2004 R1150RT.

 

The bottom line is that the bike ran very well but the AFR was centered around 14.7:1, the low end of the range was about 14:1 and the high end was 15.4:1.

 

It seems to have defaulted to a table that matched the outside air temp, that is consistent with a 20C default fueling table. But did not default to a very rich setting.

 

It could be that your Motronic is an earlier version than mine with a different behavior than mine.

 

 

[legarem]

My RT is a 2003 twin spark and yours is a 2004. I'll give you later the MPG I do with the AIT disconnected.

[roger 04 rt]

Here is the AFR log for the open IAT sensor, reset Motronic from the last post.

 

The top line is 15.4:1 and the bottom line is 14.0:1. However, I am running E10 fuel. If I were running pure gas, the lines would have values that were 4% lower, or 14.8:1 and 13.5:1 with a center point in the low 14s. On my 04RT, open loop with a BP is a few percent richer than this range.

 

[roger 04 rt]

And I guess I better add that the only reason I ran a plot with the IAT disconnected was as an answer to Legarem's question about what the mixture did when the IAT was disconnected. This isn't a viable configuration because the fueling would remain independent of air temperature. It would get 6% leaner for every 20C drop in temperature and it would get 6% richer than the plot for a 20C rise in temperature.

[roger 04 rt]

My RT is a 2003 twin spark and yours is a 2004. I'll give you later the MPG I do with the AIT disconnected.

 

If they're both twin spark models, you'd think the Motronic SW would be the same. I'll be interested to hear about the mileage. One of the reasons I worked up this thread: 1150 Mileage, was to figure out the effect of mixture richness.

 

If you mixture is 10% richer than what I showed in the plots, you should get 5% more power so gas mileage might suffer by 5%, perhaps 2 - 2.5 MPG.

[legarem]

Here is my MPG with O2 and IAT sensors disconnected, pink plug, NGK iridiums spark plugs,

 

The MPG I got is 50.79 MPG mostly with two peoples on the bike. I'm still amazed by the power difference between IAT disconnected and something like Booster Plug.

 

Today here, the temperature was 23C.

[dirtrider]

Her--- I'm still amazed by the power difference between IAT disconnected and something like Booster Plug.

 

Today here, the temperature was 23C.

 

Evening legarem

 

 

 

If you are getting a notable improvement in performance with the 02 sensor disconnected & the Intake Air Temp sensor disconnected you might want to look for the reason. That sort of points to running a bit rich in open loop for some reason.

 

Maybe something like high fuel pressure (fuel return line crimped or not fully connected), or plugged air filter (could have been water soaked therefore swelled up media).

 

For some reason your engine wants to run leaner than it runs with an operational IAT sensor.

 

Probably not much difference between the IAT plugged in & not plugged in at 20°c-23°c range but if it runs better at 10°c with the IAT unplugged then something doesn't seem right there.

 

 

 

[roger 04 rt]

Here is my MPG with O2 and IAT sensors disconnected, pink plug, NGK iridiums spark plugs,

 

The MPG I got is 50.79 MPG mostly with two peoples on the bike. I'm still amazed by the power difference between IAT disconnected and something like Booster Plug.

 

Today here, the temperature was 23C.

 

So it seems as if your bike is running well with a lean-ish mixture based on the mileage figure. Was that mostly highway miles (or UK Imperial gallons? I know you're in Quebec)

[roger 04 rt]

Her--- I'm still amazed by the power difference between IAT disconnected and something like Booster Plug.

 

Today here, the temperature was 23C.

 

Evening legarem

 

 

 

If you are getting a notable improvement in performance with the 02 sensor disconnected & the Intake Air Temp sensor disconnected you might want to look for the reason. That sort of points to running a bit rich in open loop for some reason.

 

Maybe something like high fuel pressure (fuel return line crimped or not fully connected), or plugged air filter (could have been water soaked therefore swelled up media).

 

For some reason your engine wants to run leaner than it runs with an operational IAT sensor.

 

Probably not much difference between the IAT plugged in & not plugged in at 20°c-23°c range but if it runs better at 10°c with the IAT unplugged then something doesn't seem right there.

 

 

 

Good Evening DR,

 

On the one hand I agree with you that his experience of the motorcycle points to it running a bit rich, he's getting good roll on power and no lean hesitation he says. On the other hand his mileage is pretty good which maybe says lean-ish. And on my R1150RT disconnecting the AIT sensor leads to no air temperature correction, meaning he's using a 20C table on a 23C day (just a tad rich). If it weren't for the mileage, I'd say that there's a leakage at the AIT input, but then in a PM he measured the disconnected open circuit voltage at the AIT and it's as it should be, 5V.

 

Without an AFR gauge it's had to tell what's going on.

 

RB

[legarem]

Mileage done was little on highway but most on small country roads. My MPG was calculated in american gallons 4L for 1 gallon

[roger 04 rt]

Mileage done was little on highway but most on small country roads. My MPG was calculated in american gallons 4L for 1 gallon

 

You've done a good job taking data and investigating, I'm at a loss.

 

I will say that my bike runs pretty good no O2 and no Booster, better than with the stock O2 sensor, so perhaps that's what you're experiencing. You're not getting the lower mileage that a rich mixture would suggest.

 

The other possibility is that Open IAT sensor retards the timing and your bike runs better. I haven't had time to measure that.

[legarem]

Last night, one of my friends tried my bike and told me: What have you done on this bike ?

 

Last fall he tried it and thought boxer twins had more torque feeling than my bike had.

 

About the possibility about open IAT retarding the timing, could it be that Open IAT is advancing the timing instead of retarding it ?

 

On many of my previous bikes, advancing the timing made the motor peppier with faster acceleration.

 

For sure, since i've done the O2 and IAT disconnection, I never heard any pinging from this motor.

 

 

 

[JamesW]

Hi Roger,

I must say that when I took my ride off into the hinter lands this week to really test my mods I was most surprised to find out that I am getting better mpg (48 versus 41-43) than I have ever got since it was new in '04. Again I have disconnected O2 sensor and have a home made booster plug and a yellow ccp configuration. These changes should have richened the mixture which simple logic says the mpg should have gotten worse not better. Unless the richer mixture means the motor produces more power and as long as my riding style remains the same then I am not actually using this reserve power to go faster or start from stop quicker then I realize an increase in mpg? This was not what I expected. My 3 day ride covered 900 miles wife on board all two lane at elevations up to 6300 feet speeds from 60 to 70+ mph, just my usual riding style. Also noted an almost total lack of black soot deposited on exhaust tip. Used to get a black index finger when I touch inside of exhaust tip. I don't know what is going on but I surely do like it.

[roger 04 rt]

Last night, one of my friends tried my bike and told me: What have you done on this bike ?

 

Last fall he tried it and thought boxer twins had more torque feeling than my bike had.

 

About the possibility about open IAT retarding the timing, could it be that Open IAT is advancing the timing instead of retarding it ?

 

On many of my previous bikes, advancing the timing made the motor peppier with faster acceleration.

 

For sure, since i've done the O2 and IAT disconnection, I never heard any pinging from this motor.

 

 

 

I don't doubt the improvement you've experienced. When I ran my test of the no O2/no IAT at 20C it ran quite well. Based on my measurements and on your fuel mileage, it seems likely that your AFR range is 14.0 to 14.8 plus richer on acceleration. Not bad.

 

At 10C I guess you'll be 3% leaner which isn't bad and at 30C you'll be 3% richer so in that range you'll probably like the performance.

 

With the O2 and IAT disabled, the Motronic will still adjust for barometric pressure and battery voltage. And you will still get a cold engine oil enrichment following start up.

 

When you idle in traffic on a hot day, things may get very rich but you might be able to live with that.

 

I'm surprised that a double AIT didn't work for you as it has for several others. If you ever get it reconnected, let us know the voltage on the high side at a temperature in the 20C range and I'll compare it to mine if you'd like.

 

As DR mentioned, it's possible that your fuel pressure is higher than most, or an air restriction, or it could be that "no IAT" changes the spark-timing. Without some instruments it's all guesswork.

 

Enjoy the ride.

 

Hi Roger,

I must say that when I took my ride off into the hinter lands this week to really test my mods I was most surprised to find out that I am getting better mpg (48 versus 41-43) than I have ever got since it was new in '04. Again I have disconnected O2 sensor and have a home made booster plug and a yellow ccp configuration. These changes should have richened the mixture which simple logic says the mpg should have gotten worse not better. Unless the richer mixture means the motor produces more power and as long as my riding style remains the same then I am not actually using this reserve power to go faster or start from stop quicker then I realize an increase in mpg? This was not what I expected. My 3 day ride covered 900 miles wife on board all two lane at elevations up to 6300 feet speeds from 60 to 70+ mph, just my usual riding style. Also noted an almost total lack of black soot deposited on exhaust tip. Used to get a black index finger when I touch inside of exhaust tip. I don't know what is going on but I surely do like it.

 

Both you and Legarem run pure gas, I guess your AFR range will be a several percent lower than his. In the R1150RT Mileage post I wrote, I mentioned that between AFRs of 13.8 and 14.7 for every percent more fuel you add half a percent more power so should only lose half a percent to mileage. However, if the burn is better, you might lose none and if you're in a lower gear sooner, you will likely gain mileage due to running at a better Brake Specific Fuel Consumption point.

[legarem]

Today the temp was 28C. I did a 400 km ride and my MPG seems even better than the previous given numbers, I'll look at the precise numbers tomorrow.

 

Sometimes, my bike did some pinging at high speed when accelerating from 100 kmh and over. it did that when it was in stock condition but it seems less severe with the mods done.

 

As stated, double IAt and no O2 sensor work but the results are on the poor side compared to open IAT and No O2 sensor

 

 

[roger 04 rt]

Today the temp was 28C. I did a 400 km ride and my MPG seems even better than the previous given numbers, I'll look at the precise numbers tomorrow.

 

Sometimes, my bike did some pinging at high speed when accelerating from 100 kmh and over. it did that when it was in stock condition but it seems less severe with the mods done.

 

As stated, double IAt and no O2 sensor work but the results are on the poor side compared to open IAT and No O2 sensor

 

 

Yes, you've made the point about no IAT being better than a "richer" IAT in the case of your motorcycle. What we need to find is a reason why that should be the case.

 

Because of the variation in mixture with temperature and the unknown effect on timing; because you're getting higher mileage (leaner) and because of the GS-911 and AFR readings on my similar bike, a "no IAT" configuration can't be considered a solution for better running Oilheads as a general case, unless or until we could get some measurements that explain what's happening.

 

Mileage alone isn't a good measurement as it depends on so many variables. Does someone have a GS-911 nearby that you could borrow? Can you monitor the fuel pressure coming out of the regulator? There will eventually be an explanation. Let us know how we can help.

[JamesW]

No no Roger, I am not running with no AIT. I have two thermistors connected in series so my moto thinks it is 20C colder than what it really is. That plus O2 disconnected and a jumper simulating a yellow code plug as well.

[legarem]

Roger

 

I don't have a GS-911 on hand and will probably not monitor the fuel pressure at least until I will have to undress the bike for repairs.

 

When you tried no IAt and no O2 with your bike did it feel better or not better than with O2 disconnected with Booster plug connected ?

[legarem]

Hi James

 

Before going to yellow code did you have a pink one ?

 

If yes, what's the difference between the pink and yellow ?

 

What is the internal wiring modification to do to go from a pink one to yellow one ?

 

Thanks

 

 

[roger 04 rt]

No no Roger, I am not running with no AIT. I have two thermistors connected in series so my moto thinks it is 20C colder than what it really is. That plus O2 disconnected and a jumper simulating a yellow code plug as well.

 

JamesW, Yes, I understood your configuration, sorry if something I wrote confused that point. Thanks for clarifying.

[roger 04 rt]

Hi James

 

Before going to yellow code did you have a pink one ?

 

If yes, what's the difference between the pink and yellow ?

 

What is the internal wiring modification to do to go from a pink one to yellow one ?

 

Thanks

 

 

Pink connects 30-87-87a

Yellow connects 30-87

 

87a on 1150s (different on 1100s) signals which heads, cams, and intake tubes are used, therefore telling the motronic which model it is.

 

If you go with yellow, you're telling the Motronic that there are narrower tubes and different cams/heads.

 

[JamesW]

Hi Legarem,

As Roger says jumper pin 30 to 87 for yellow. I have a pink code plug as that is what came with the bike and I get a slight hesitation and slight uneven idle with pink. I had been using the green configuration ( 30 to 86) with better results than with pink when I read one of Roger's posts to someone else and in it he suggested trying yellow rather than green so I tried it and all I can say is my bike runs perfectly. Absolutely the smoothest idle I have ever seen on a motorcycle with good acceleration with no hint of hesitation during cruise at any RPM. Of course that is with no O2 sensor and modified air temp sensor as in two thermistors in series. Oh, and much to my surprise great fuel economy as well. Haven't decided if I still am going to put it on the dyno because it is what it is and I'm through tinkering as I am totally satisfied with the way it runs and wouldn't change a thing anyway. I am curious to know what the A/F ratio actually is but again it is what it is and I like whatever it is. In 8 years I am finally happy with the big blue beast. Now, I did set both TB brass screws out from seated exactly 1-1/4 turns and balanced the TBs with the forbidden throttle stop screws after a thorough cleaning. I then set the throttle position sensor pot for .360 volts which is where it ends up if I do the Rob L. zero zero adjust as described on the IBMWR sight. I believe this adjustment is specifically for an R1100 but I see no reason why it shouldn't apply to an 1150. Hey, what can I say, I love it! I could just sit and listen to it purr at idle. In fact, it idles maybe even smoother than my pretty darn smooth '81 R100RT which i plan to be buried with someday.

[JamesW]

Oh, forgot to mention one other thing I did and that is I installed NGK plugs that are hotter by, I think, two ranges than the factory installed plugs. The secondaries run a lot cleaner now with no oil fouling. I am also considering disconnecting the crank case ventilation hose from the bottom of the air box as this is most likely the main source of coking in the throttle bodies. OK, shame on me but this pales in comparison to what all these idiots do to the air we breath by running these god awful diesel powered stinking noisy pick-up trucks.

[roger 04 rt]

Great description JamesW. I've pretty well exhausted all the data that I want to take on the AFR versus various configurations. In all honesty, I doubt AFR changes much with 87a. However timing could. I think when I get back in June, I'm going to start gathering some timing info with the GS-911. As we all know, timing has a very significant impact on how an IC engine runs.

[legarem]

So today, I've done ride with the double IAT in series and O2 disconnected. MPG is: 55.68. Today it is 29C. Speed was mostly near 100 km/h. The biggest difference with IAT disconnected is NO pinging at all and smoother idle. I think that the power increase I felt with IAT disconnected is not really there at high temperatures like 28-29C

 

Yesterday i Recorded 53.44 MPG in the same conditions with IAT disconnected

 

I strongly suspect that disconnecting the IAT gives timing advance compared to BP or double IAT in series.

[roger 04 rt]

Lots of interesting information. So today is warm in Montreal 29C which means your mixture richen by 3-4%. Surprising that you could notice the difference. The good mileage would say not too rich but losing the good running on a 3-4% richer mixture is hard to understand. The Motronic often varies the fuel more than that if you look at the AFR plots over in my O2 thread.

 

Could you measure the voltage between the IAT pins with the double IAT connected and ignition on. It would be best if the bike had cooled down so there was no self heating of the airbox relative to ambient. I'd be interested in the result and would check it with mine.