Hello Chaps :biggrin:
I've been replacing lower throttle cables today ...Its a crap job...tank off , battery box out , throttle bodies off , Bowden box out ...you catch my drift ..its a crap job.
(Thank God I don't have an ABS pump)
But I digress...when all is done and the pig has been rebuilt , it all needs to be set up and calibrated, so I thought I might as well check the ZERO = ZERO calibration as the pig has been popping a lot on the overrun lately , which indicates its running too lean.
Now all the literature I've read, indicates that zero is = to 10mV and TPS setting is at 360 to 400 mv , but I found an article by a guy, who seems to know what he's talking about who claims that ZERO is actually = 250mv. So being the intrepid adventurer that I am , I set up the pig using his settings, and ...hey presto...the ole girl is pulling like a train ...popping and farting have gone.
Have a look at this extract from his post and the link to the whole article is at the bottom. If you haven't messed with your throttle body stops ....DONT...but if you have adjusted the factory setting , it might be worth while reading this article and trying out these settings.
Comment on Earlier Posts
In the earlier posts in this thread there are mistakes or omissions that I have found. The biggest error is the conventional understanding of what rotating the throttle does after a Motronic reset and recal. As I mentioned, this is a work-in-progress. I have a new recommendation for zero=250 later in the post.
New Measurements
I spent a few hours yesterday making measurement of the TPS and Motronic for small throttle angles and found quite a few interesting things. Among the things I learned (and although I can see vestiges of the factory paint), I see that someone performed zero=zero on my R1150 since there is no fully intact paint. The BBSs are about equal so I'm not too concerned but will go back and reset it at some point.
To make the measurements, I attached a good DVM between pins 1 and 4 or the TPS and connected the GS-911 to the diagnostic port. This way I could measure the voltage change versus throttle angle change as reported by the Motronic. I was careful to move the TPS very slowly (by rotating it with the throttle lock on), and find the trip point for each reading of the GS-911. It outputs angles with a resolution of 0.32 degrees. So the angles it registers are: 0, 0.32, 0.64, 0.96, 1.28, 1.92, etc. I also monitored the Idle Switch Off indicator reported by the GS-911. Lastly, I measured (and then calculated to confirm) how much physical rotation of the TPS per 10 mV (it's tiny) of voltage change on pin 1 (the high resolution wiper).
Here's what I've found:
1) TPS cal (rotating the throttle) does not have any effect on the voltage-to-throttle angle as measured by the Motronic. This was a surprise because we all "believed" that TPS cal (rotate the throttle twice) learns the idle and full scale positions. I set the TPS as low as 300 mV and as high as 375 mV, performed a full reset (10 minutes) and recal. In spite of that, the point at which the Motronic/GS-911 transitioned from reporting 0.32 degrees to 0.64, 0.96 and the point at which the Idle Switch reported OFF were the same whether I set the TPS to 300, 350 or 375 mV.
It now seems clear to me that the reason for setting the TPS is to position it to 0.48 degrees, which is always approximately 340 mV to 350 mV.
2) The A/D converter in the Motronic is 8 bits (expected) and the step size for each "bit" of the A/D is approximately 20 mV. The Motronic reported step sizes are 0.32 degrees, which equals 60 mV, which means each bit of the A/D is about 0.11 degrees (20 mV). That means one degree is about 200 mV (187.5 to be exact). So the angle to voltage conversion measured (and then calculated by me) below. Because the A/D has some tiny fluctuations (noise) these values can change by 10-20 mV.
0.00 degrees: 250 mV to 309 mV
0.32 degrees: 310 mV to 369 mV
0.64 degrees: 370 mV to 429 mV
0.96 degrees: 430 mV to 490 mV
Idle Switch Off: ~430 mV
3) Using a feeler gauge under the throttle stop, I measured that every 0.1 degree of TPS rotation is about 0.0025" of movement at the TPS locking screw. This means a 10 mV change in DVM reading is the result of about 1-2 thousandths of an inch of movement!
4) On my R1150 the A/D "noise" at small throttle angles seems very good, less than one bit. That means that sometimes the transition for, say, 0.96 degrees is at 410 mV and sometimes it is at 430 mV. 0.96 degrees is the point that the Motronic reports Idle Switch: OFF.
5) If you want to readjust the TPS and throttle stops (because someone else changed them) zero=zero is the wrong procedure. It certainly leads to the throttle angle being opened too much (10 mV at zero degrees, then to 370 mV, which means the throttle is opened 1.92 degrees). Based on a 340 mV target for the TPS (confirmed with the GS-911 and equal to the mid-point of 0.32 degrees), the throttle is meant to be opened about 0.48 degrees and the rest of the air comes from the BBS. (I could be off a bit on the 1.92 degrees since there is no spec for angular rotation below 250 mV on the Bosch TPS.)
Looking at the TPS data sheet, I have an explanation for why the requirement to rotate the throttle twice after a Motronic reset on the R1150 (the R1100 may be learning it on-the-fly, or BMW may have fixed a problem by introducing the procedure on the R1150), since it doesn't seem to calibrate the end point. There are two potentiometers in the TPS. The fine-tps (0-23 degrees throttle) has it's upper and lower points specified. TPS-coarse has only it's upper point spec'ed. That means that rotating the throttle allows the Motronic to measure and learn the crossover point and the start of tps-coarse. It may be doing this by using the fine-tps to measure the starting point of the coarse-tps, thereby having a seamless crossover between the two.
Also, I now also can see why moving the TPS idle setting to 370-385 mV can affect engine operation, at least temporarily, especially on the no-cat configuration of the R1100. At that voltage, the Motronic is just starting to register 0.64 degrees, so the Motronic then goes up to the next 0.32 degrees more quickly. This would give a slight rich fueling bias for throttle angles below (I'm estimating) 5 degrees. I doubt that it is a permanent benefit but could be, very slightly around idle. (Going a little further with the reasoning, since zero=zero opens the throttle too much, it makes sense that a higher TPS voltage would get the TPS reading by the Motronic closer to the actual throttle-angle-plus-BBS air flow. On the Closed Loop Oilheads, Adaptation Values will fix this up, but as you know, adaptation is not perfect. Therefore, it is better to get it right from the start.)
Recommendation
The procedure I suggested earlier in the thread for restoring the throttle stops and TPS will work but now seems too complicated. I also realized you can set the TPS with voltage, something I didn't think was possible because of the conventional-wisdom of what rotating the throttle twice did after reset. I still believe that the GS-911 or LED (for R1100) is the preferred route for setting just the TPS because it is a Closed Loop process that includes the Motronic.
Although I don't advocate changing the throttle stops or TPS, for someone (like me?) who has had their TPS Lentini-ized by zero=zero and wants to get it set correctly, a zero=250 procedure can be used.
Begin by setting zero degrees throttle to 250 mV (instead of 10 mV recommended in zero=zero). Then the left throttle should be rotated to 340-350 mV, which will rotate the throttle open 0.48 degrees. Then just follow the rest of the Lentini procedure. That will undoubtedly require the BBSs to be opened more than two turns. I will experiment with this on my bike to see how many turns are required when I have time.
Next Tests
My next experiments will be to close the BBSs and see how much the throttle needs to be opened to idle at 1100 and at an AFR of 14.7 to 1. Then I will see how many turns the BBSs can be opened before the RPMs stop increasing.
Here is the whole post link https://forums.bmwmoa.org/showthread.php?73962-TPS-Alignment-Idle-Speed-Adjustment-Beyond-Zero-Zero
I've been replacing lower throttle cables today ...Its a crap job...tank off , battery box out , throttle bodies off , Bowden box out ...you catch my drift ..its a crap job.
(Thank God I don't have an ABS pump)
But I digress...when all is done and the pig has been rebuilt , it all needs to be set up and calibrated, so I thought I might as well check the ZERO = ZERO calibration as the pig has been popping a lot on the overrun lately , which indicates its running too lean.
Now all the literature I've read, indicates that zero is = to 10mV and TPS setting is at 360 to 400 mv , but I found an article by a guy, who seems to know what he's talking about who claims that ZERO is actually = 250mv. So being the intrepid adventurer that I am , I set up the pig using his settings, and ...hey presto...the ole girl is pulling like a train ...popping and farting have gone.
Have a look at this extract from his post and the link to the whole article is at the bottom. If you haven't messed with your throttle body stops ....DONT...but if you have adjusted the factory setting , it might be worth while reading this article and trying out these settings.
Comment on Earlier Posts
In the earlier posts in this thread there are mistakes or omissions that I have found. The biggest error is the conventional understanding of what rotating the throttle does after a Motronic reset and recal. As I mentioned, this is a work-in-progress. I have a new recommendation for zero=250 later in the post.
New Measurements
I spent a few hours yesterday making measurement of the TPS and Motronic for small throttle angles and found quite a few interesting things. Among the things I learned (and although I can see vestiges of the factory paint), I see that someone performed zero=zero on my R1150 since there is no fully intact paint. The BBSs are about equal so I'm not too concerned but will go back and reset it at some point.
To make the measurements, I attached a good DVM between pins 1 and 4 or the TPS and connected the GS-911 to the diagnostic port. This way I could measure the voltage change versus throttle angle change as reported by the Motronic. I was careful to move the TPS very slowly (by rotating it with the throttle lock on), and find the trip point for each reading of the GS-911. It outputs angles with a resolution of 0.32 degrees. So the angles it registers are: 0, 0.32, 0.64, 0.96, 1.28, 1.92, etc. I also monitored the Idle Switch Off indicator reported by the GS-911. Lastly, I measured (and then calculated to confirm) how much physical rotation of the TPS per 10 mV (it's tiny) of voltage change on pin 1 (the high resolution wiper).
Here's what I've found:
1) TPS cal (rotating the throttle) does not have any effect on the voltage-to-throttle angle as measured by the Motronic. This was a surprise because we all "believed" that TPS cal (rotate the throttle twice) learns the idle and full scale positions. I set the TPS as low as 300 mV and as high as 375 mV, performed a full reset (10 minutes) and recal. In spite of that, the point at which the Motronic/GS-911 transitioned from reporting 0.32 degrees to 0.64, 0.96 and the point at which the Idle Switch reported OFF were the same whether I set the TPS to 300, 350 or 375 mV.
It now seems clear to me that the reason for setting the TPS is to position it to 0.48 degrees, which is always approximately 340 mV to 350 mV.
2) The A/D converter in the Motronic is 8 bits (expected) and the step size for each "bit" of the A/D is approximately 20 mV. The Motronic reported step sizes are 0.32 degrees, which equals 60 mV, which means each bit of the A/D is about 0.11 degrees (20 mV). That means one degree is about 200 mV (187.5 to be exact). So the angle to voltage conversion measured (and then calculated by me) below. Because the A/D has some tiny fluctuations (noise) these values can change by 10-20 mV.
0.00 degrees: 250 mV to 309 mV
0.32 degrees: 310 mV to 369 mV
0.64 degrees: 370 mV to 429 mV
0.96 degrees: 430 mV to 490 mV
Idle Switch Off: ~430 mV
3) Using a feeler gauge under the throttle stop, I measured that every 0.1 degree of TPS rotation is about 0.0025" of movement at the TPS locking screw. This means a 10 mV change in DVM reading is the result of about 1-2 thousandths of an inch of movement!
4) On my R1150 the A/D "noise" at small throttle angles seems very good, less than one bit. That means that sometimes the transition for, say, 0.96 degrees is at 410 mV and sometimes it is at 430 mV. 0.96 degrees is the point that the Motronic reports Idle Switch: OFF.
5) If you want to readjust the TPS and throttle stops (because someone else changed them) zero=zero is the wrong procedure. It certainly leads to the throttle angle being opened too much (10 mV at zero degrees, then to 370 mV, which means the throttle is opened 1.92 degrees). Based on a 340 mV target for the TPS (confirmed with the GS-911 and equal to the mid-point of 0.32 degrees), the throttle is meant to be opened about 0.48 degrees and the rest of the air comes from the BBS. (I could be off a bit on the 1.92 degrees since there is no spec for angular rotation below 250 mV on the Bosch TPS.)
Looking at the TPS data sheet, I have an explanation for why the requirement to rotate the throttle twice after a Motronic reset on the R1150 (the R1100 may be learning it on-the-fly, or BMW may have fixed a problem by introducing the procedure on the R1150), since it doesn't seem to calibrate the end point. There are two potentiometers in the TPS. The fine-tps (0-23 degrees throttle) has it's upper and lower points specified. TPS-coarse has only it's upper point spec'ed. That means that rotating the throttle allows the Motronic to measure and learn the crossover point and the start of tps-coarse. It may be doing this by using the fine-tps to measure the starting point of the coarse-tps, thereby having a seamless crossover between the two.
Also, I now also can see why moving the TPS idle setting to 370-385 mV can affect engine operation, at least temporarily, especially on the no-cat configuration of the R1100. At that voltage, the Motronic is just starting to register 0.64 degrees, so the Motronic then goes up to the next 0.32 degrees more quickly. This would give a slight rich fueling bias for throttle angles below (I'm estimating) 5 degrees. I doubt that it is a permanent benefit but could be, very slightly around idle. (Going a little further with the reasoning, since zero=zero opens the throttle too much, it makes sense that a higher TPS voltage would get the TPS reading by the Motronic closer to the actual throttle-angle-plus-BBS air flow. On the Closed Loop Oilheads, Adaptation Values will fix this up, but as you know, adaptation is not perfect. Therefore, it is better to get it right from the start.)
Recommendation
The procedure I suggested earlier in the thread for restoring the throttle stops and TPS will work but now seems too complicated. I also realized you can set the TPS with voltage, something I didn't think was possible because of the conventional-wisdom of what rotating the throttle twice did after reset. I still believe that the GS-911 or LED (for R1100) is the preferred route for setting just the TPS because it is a Closed Loop process that includes the Motronic.
Although I don't advocate changing the throttle stops or TPS, for someone (like me?) who has had their TPS Lentini-ized by zero=zero and wants to get it set correctly, a zero=250 procedure can be used.
Begin by setting zero degrees throttle to 250 mV (instead of 10 mV recommended in zero=zero). Then the left throttle should be rotated to 340-350 mV, which will rotate the throttle open 0.48 degrees. Then just follow the rest of the Lentini procedure. That will undoubtedly require the BBSs to be opened more than two turns. I will experiment with this on my bike to see how many turns are required when I have time.
Next Tests
My next experiments will be to close the BBSs and see how much the throttle needs to be opened to idle at 1100 and at an AFR of 14.7 to 1. Then I will see how many turns the BBSs can be opened before the RPMs stop increasing.
Here is the whole post link https://forums.bmwmoa.org/showthread.php?73962-TPS-Alignment-Idle-Speed-Adjustment-Beyond-Zero-Zero
