IBMWR zero=zero procedure TPS voltage
 

I'going to do the zero=zero procedure from the ibmwr.org site in yet another attempt to reduce surging. They outline parms for the TPS voltage of .37~.4 volts which are for a R1100RS with motronic 2.2.

Do any of you bums know what the TPS voltage range is for our bikes, r1100s w/ motronic 2.4?

I remember recently saying that the max voltage a injector gets is 4 volts while I was remembering in my mind the tuning problems we had with our 93 beta units. Eron Flory corrected me at once on the mind laspe. I was thinking TPS while talking injector voltage.

The TPS voltage is important and is the same for the S units as it was for the older units, with 4 volts being the point of default. There are several ways of measuring this voltage, how smoothly it progresses as the throttle is twisted, and how high it gets in relation to rich burn.

When I orginally wrote about the primary balance needed between the two throttle bodies to get smoother and more postive response it raised lots of questions and Rob Lentini, wrote them down and offered these to the clubs for publications. I had been tuning a 93 Beta to run at the East Coast Timing Association and we seemed to be able to tune in a little more thruout the RPM range by carefully resetting the T bodies, the low end voltage, and the high end voltage.

In my opinion it is still worth doing to your S. My 99 has always run smooth and strong right off idle and on up because its two throttle bodies have had their butterflies reset so that both sides pull equally when it is at absolute dead idle. (Both air screws completely closed)

The care is taken to get the body flow equal after the bike is broken in and the valves and rings have seated. At that point the basis settings (the ones that BMW says will void your warrenty) may be changed.

Be very careful however because changing the butterfly setting on the left throttle body changes the primary mixtures to both. If possible limit your adjustments to the right body. This is not always possible however.

A final setting in the 3.85 range is about right when running at sea level while a setting of 3.95 might be right for a bike with open pipes. 3.60 is about as low as I have seen and that was on a bike tuned for the higher mountain states. Best,

I've lately taken a liking to about .395 volts.
Some guys like amounts a bit higher around .410.

How do they get it to run with a 4.10 voltage reading when the default goes into effect at 4 volts? They may LIKE the 4.10 reading because of the rich mid range but the bike is in "limp home" mode at above 4 volts. This is explained clearly in the factory service material. No wonder some of the dyno readings have been so low on some bikes ..........even though they had pipes, linnies, chippies, induckies, and the like. Even 3.95 is very high unless you have cloged injectors giving a lean mist.

Its not as if you grow to "like" something.............its what it will do for max horsepower up top. If you are running a otherwise perfect R11S that has had its TPS setting changed to peak at 4.10 volts then you most likely have a slug above 130......if it even will get to that. Best

Hey jim were talking .04 volts or 400mv


do the injectors really open at such a low voltage under 5 volts? I never scoped one

Uhhh, Curve, that's .410v or 410 millivolts not 4.1 volts. I personally run mine at .355v without any problems.

Micky :)

Injectors dont use voltage to detirmine open/close time. The computer sends ground signal to open/close injector, dwell time. If im not mistaken, a injector uses 12v that is always on while the engine is running.

John

John

I know they open and close with no inbetween...... 12volts makes sense thats why I questioned Jim's 5volts.

Injectors dont use voltage to detirmine open/close time

of course they do

it makes no difference if they trigger with ground or B+(12v) it's still triggered by voltage potential across a coil

The injectors use 12 volts. The TPS use .022 to .400 volts. Thanks for reminding me where the decimels are. Above .400 is default. I always say 4 volts but it is .400 instead of 4.

The same thing happened in the twin spark article. I talked in terms of (slang) "mil seconds" when in actuality it would be in hunderd thousands of a second. Thanks for the correction. System defaults at .400 of one volt.

In tuning the TPS I am more interested in the smoothness of the voltage rise as well as the actually low voltage (switch turned on but no engine running) and the high voltage (twist grip turned to at least 75 degrees of butterflys total of 90 degrees possible) because this smoothness of transition seemed to affect low end response. I found some improvement when I coated all connections related (eprom, tcp, ect) with "conductivity enhanser. I used "Stablelent 22" which is made in Canada and used by Apple in some of their assembly. That was ten years ago and there may be updated methoids by now. You want your voltage to rise smoothly in a progressive, no jerky manner, as you twist the grip and read the voltage as it rises (ignition on, engine not running) from a low of lets say .025 to a high of lets say .365. Best, and thanks for the correction.........

Put the bike on a gas analyzer and set the TPS for a CO reading of
1.5% with the O2 disconnected. This will result in the best idle
and throttle response. Then go back and read the TPS voltage for
future reference. Remember, the TPS output voltage is a proxy
for input air flow and as such is key in determining the overall
fuel mixture based on the Motronic fuel maps.

A CO reading of 1 to 1.5% is the ideal CO for all types of fuel
injection systems including bikes. Using a gas analyzer is always
the proper way to set the fuel mixture for the optimum air/fuel
ratio (Lambda).

You could also run the bike on a dyno and tweek the TPS at various
RPMs to maximize the torque and data log the TPS values. Then you
could evaluate the data and determine where the TPS should be set
for best overall performance over the full range of RPMs.

Obviously, these methods are not simple and are time consuming, but
they will achieve the best results versus using a less accurate method.

Have Fun
Loren
www.systemsc.com
'04 BCR

Jim

Some of the best chemical I've used for carbon contacts at low current is Cramolin Red I used it to recondition high end Stereo potentiometers)

> >
You could also run the bike on a dyno and tweek the TPS at various
RPMs to maximize the torque and data log the TPS values. Then you
could evaluate the data and determine where the TPS should be set
for best overall performance over the full range of RPMs.


Now THERE is a laughable tack-on kludge that wouldn't work, since anyone with a vague familiarity with these systems knows that at the throttle openings where max torque would occur (which are near wide open) that the tps value isn't even used. No motogp team would ever do that. I bet BMW is laughing at these ignorant ideas. Wait, does that line of "reasoning" sound familiar?

That having been said, the CO parts of the comments are good an accurate. AFR is better still, but Loren's idea of using a CO meter IS a much better idea than any blindly selected value.

Btw, yes, any idiot can read the service manual and see that it calls for a fault above 400mv. A brighter guy can measure a half dozen and see that it doesn't fault that early (any engineer or techie realizes that margin is designed in)

But again, I do agree with Jim insofaras folks running 450-500mv are simply defaulting rich, and arent' really adjusting/tuning anything.

Roger needs to read better.

It is stated that at each RPM the torque can be maximized for THAT RPM,
given various TPS settings. Just as the torque can be changed and maximized
by varying the timing and finding where the torque becomes maximum for
THAT RPM. This is the method used for optimizing fuel and ignition maps
when using a dyno.

Please tell us your method, Roger, for programming Motronic chips and properly
setting up a bike once significant mods are made! You must have this answer
since you're the technical moderator, or do you just follow BASIC guidelines
without the ability to think and provide alternative solutions to problems.

Loren

i always use .350 for the base idle setting, which puts you in the middle of the green zone if you are using the moditec/gt1 to do the idle "switch" tps setting.

they will usually just idle at this when hot with the airbleeds shut, but you need to wind the rh stop screw out to balance the idle stop settings, which reduces the idle even more.

I am not the one who needs to read or think better. Torque can't be optimized via tps fiddling because (and I'll type more slowly this time, for clarity) at the throttle positions where torque is maximized, the tps is ignored. Again Loren, as I had to request a couple months ago, please lay off the personal insults and implications of following basics without thought. Those of us who think know what can and can't be done via the tps.

To be fair, I think it was you that provoked Loren this time by using words such as 'laughable' and 'ignorant' in relation to his suggestion. A bit of 'Pot and Kettle' IMHO.

That may be so, and if so, I apologize. I was trying to stick to pointing out the material that was wrong, and taking time to 'give props' to the part that was right. I didn't start out accusing anyone of not thinking, so it's not quite pot and kettle.

Even then however, I was just using his own words from earlier in the day on another FI thread where he was expounding on things he has no experience with, and seems only partially to understand, where he nevertheless ridiculed others efforts. Others who've done good work, and don't repeatedly post bad advice and wrong information. If you hang around the board a bit longer, you'll notice a pattern of this by Loren. It's a shame, because he does know the stuff better than the average bear. But he repeatedly tries to apply knowledge of systems he does appear to understand, to those he clearly doesn't, and then, when corrected, even gently, goes on a rant. As for ignorance of what he spoke of, I stand by that.

Once again. Each RPM has an ideal torque (a max), but still less
than the overall and FINAL maximum torque. As an example:
If at 2000 RPMs the timing is retarded 5 degrees from the normal
setting, the torque at that RPM with decrease. Also, if the timing is
advanced, a point will be reached where the torque again decreases.
Therefore, one can find a max torque for THAT RPM by varying the
engine variables such as the timing and the TPS setting.

I've provided an alternative to methods being used, which I've
found work great on my new BCR. My bike starts better, idles
better (none of that shaking), and has better throttle response.
If you think my appoach is flawed, then ignore it as you
apparently have.

Loren
'04 BCR

What a geek thread.??
.
It always fun to see tech heads argue:) (makes for good reading when I'm trying to fall asleep)
.
Theres only one answer to it all. 999

Yes, geeks we are. Woe to those that try to actually understand 'stuff'

Loren, I get the procedure and it's ok if you have access to all of that on whatever car you're working on. One doesn't move the TPS about however. It's an independent variable, not a dep, when programming.
I didn't see any method someone could actually use provided (not be me either, to be fair) so it's hardly an alternative. At any rate, given your anti-kludge philosophy, I'm suprised you'd lower yourself to the tps kludge :) (even under the limited conditions where it even works - which certainly don't include maximizing torque) Adjusting tps to get max torque is less than a kludge, because it doesn't work at all. That input is not even regarded.

At any rate, being a geek, I think it's an interesting topic and prefer to make nice, so my apologies to Loren if any of the rebuttal seems harsh (and to Pat, for possibly putting him to sleep on the job) :)