Non-linear TPS readings vary between ECUs - Ducati.ms - The Ultimate Ducati Forum
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post #1 of 19 (permalink) Old Aug 13th, 2014, 12:51 am Thread Starter
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Non-linear TPS readings vary between ECUs

I've been setting up to try some different maps mostly to try to clean up the throttle response in stop/start traffic on my M620 with slip-ons and filter.

Having bought a used 5AM HW103 ECU for testing, I was surprised to find that the TPS was showing a very different reading to my standard ECU (59M)

The 620 has a non-linear TPS which I understand means that at a given voltage, all ECUs should read the same TPS value.

I didn't test the TPS output voltage yet, but it seems strange to me that one ECU would be reading 2 degrees at idle, and the other reading 2.9 degrees.

If I do a TPS reset by the book I could still have an incorrect reading at the ECU, so I guess I will need to add an extra step and zero the ECU TPS reading at zero degrees throttle.

Anyone seen this type of thing before?
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post #2 of 19 (permalink) Old Aug 13th, 2014, 7:49 am
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See if this helps:
BikeBoy.org - Ducati 2V Non Linear TPS Baseline Adjustment

Jerry Duke
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post #3 of 19 (permalink) Old Aug 13th, 2014, 10:09 pm Thread Starter
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Thanks Jerry.

In fact that document has been a great reference, but there is still a piece of the puzzle missing for me.

Step 1. Set to 150 mV at butterfly closed
Step 2. Set the butterfly opening to 2.7 degrees at the ECU

From the article
Quote:
620 - 434mV - 2.7 degrees
The relationship between degrees and voltage under 30 degrees throttle opening is: mV = (degrees x 105) + 150
This all suggests that the ECU TPS reading at a given voltage should be the same for all ECUs. I'm assuming that the Mathesis/VDST/DucatiDiag TPS reset has no impact on an ECU designed for non-linear.

In my case if I swap ECU, I need to either modify the TPS position or change the throttle stop screw and air bleeds to achieve the correct TPS reading (at a different butterfly opening).

I guess I will need to do a full TPS position reset and stick with one ECU.
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post #4 of 19 (permalink) Old Aug 14th, 2014, 10:16 am
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Quote:
Originally Posted by warwickh View Post
Thanks Jerry.

In fact that document has been a great reference, but there is still a piece of the puzzle missing for me.

Step 1. Set to 150 mV at butterfly closed
Step 2. Set the butterfly opening to 2.7 degrees at the ECU

From the article


This all suggests that the ECU TPS reading at a given voltage should be the same for all ECUs. I'm assuming that the Mathesis/VDST/DucatiDiag TPS reset has no impact on an ECU designed for non-linear.

In my case if I swap ECU, I need to either modify the TPS position or change the throttle stop screw and air bleeds to achieve the correct TPS reading (at a different butterfly opening).

I guess I will need to do a full TPS position reset and stick with one ECU.
Your findings are very interesting. I hope someone else could chime in with FHE from swapping ECU to ECU.
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post #5 of 19 (permalink) Old Aug 14th, 2014, 11:05 am
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I found a link that says 5AM ECU's and 59M ECU's are interchangeable unless they have a red key and immobilizer. Then you have to reflash the ECU and remove the immobilizer.
So if you are using the same map on both ECU's I don't know why you would get different readings. The voltage reading isn't affected by the ECU just read by the ECU and applied to the map installed on the ECU.
But my knowledge of electricity is limited to the switch being off or on, beyond that I'm lost...
GOOD LUCK!!

Jerry Duke
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post #6 of 19 (permalink) Old Aug 16th, 2014, 4:48 am
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wacky

what's the # on the 5am?

i wonder if the voltage at the tps supply is slightly different.

maybe the earth path through the heat sink has some slight resistance.

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post #7 of 19 (permalink) Old Aug 17th, 2014, 8:42 pm Thread Starter
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Hi Brad,

The replacement ECU is a
Hardware: IAW5AMHW103
Drawing: 1210A11DG12
Stickers: M620DUCATI027 - SA11DG12
Produced 09/2002

The original is
Hardware IAW59MHW010
Stickers: M620DUCATI013 - S20DG119
Produced 02/2004

I believe that the Monster 620 always used a non-linear TPS.

One thing I noticed is that the maps on each ECU uses different break-points. the 59M uses 2.0, 2.5, 3.0, 3.5 then 4.0 degrees meaning 80 degrees end to end.(Last break-point is still at 82.0 in each case)
The 5AM uses 2.3, 2.7, 3.1, 3.5, then 4.0 degrees meaning 79.7 degrees end to end.

So it is possible that the TPS was adjusted differently from the factory to match this different range.

I'll need to check if there's any difference in the voltage.
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post #8 of 19 (permalink) Old Aug 19th, 2014, 4:39 am
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break points vary for many files, it's just the way they do stuff. it seems somewhat arbitrary at times.

i can't see any reason for the voltage variation.

5am 103 can be a bit wacky. they don't like 610 files either.

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post #9 of 19 (permalink) Old Aug 26th, 2014, 8:59 pm Thread Starter
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OK, so I got round to testing the TPS voltages.

With the 59M installed
At idle - 2 degrees in DucatiDiag, TPS voltage 505mV.

With the 5AM installed
At idle - 3 degress in DucatiDiag, TPS voltage 488mV.

So it doesn't really answer any questions, but my conclusion is that the 5AM is reading pretty close to the spec, but the 59M reads low. (And possibly provides a different supply voltage)
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post #10 of 19 (permalink) Old Aug 27th, 2014, 5:07 am
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i'd say there's something wrong with the 59m.

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