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Tightmopedman9

Tuners Rejoice! Free Tuning For M4.4!

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Per the specification, yes, it has a range of 0 to 250kPa gauge, which as you say, is 0-36.3 PSIg. How is that too good to be true? :lol:

The chart on table 4 is just labeled strangely to accommodate the differential pressure versions as well. Note the text explaining figure 4 at the beginning of page 4:

Figure 4 shows the sensor output signal relative to pressure input.

So it's an absolute pressure measurement across the sensing element, but in the "gauge" version of the sensor, one side is open to atmosphere.

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Per the specification, yes, it has a range of 0 to 250kPa gauge, which as you say, is 0-36.3 PSIg. How is that too good to be true? :lol:

The chart on table 4 is just labeled strangely to accommodate the differential pressure versions as well. Note the text explaining figure 4 at the beginning of page 4:

So it's an absolute pressure measurement across the sensing element, but in the "gauge" version of the sensor, one side is open to atmosphere.

When I bought the GP I was thinking about 2 things:

- I don't have to worry about barometric pressure and its readings should be equivalent to the readings of my boost gauge;

- I can read higher psig (36.3) than the AP (which would be arround 21.6 psig)

However when I started doubting about the meaning of the data sheet I was already telling to my self "oh this maybe reads only 0-250kPa absolute and not gauge pressure" so I said to good to be true. But probably this is really true.

I've just enquired them to be sure :)

For those who runs more than 20/21psi this may be a good solution. I will not be runing more than 19/20psi max on my 18T but I would like to have enough upper space to accomodate eventual higher boost pressures so I chose the GP.

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I got the answer from Freescale and my doubts had reason to exist. There are no doubts any more! :)

"Hello Miguel,

You´re correct, the MPX4240GP is a gauge pressure sensor, please disregard the title of the figure 4 in the datasheet, it should say "Figure 4. Output versus Differential Pressure". I will request our documentation team to fix this, thanks for the heads up!!

Have fun!

Josh"

Edited by S70-R
  • Upvote 2

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Today I tried to get COP working. I made the necessary hardware modifications to the ECU; 10K, 150Ω and 47Ω resistors were added. I connected ME7 coils on a ME7 wiring harness to the ECU as following:

B11 - Cylinder 1

B10 - Cylinder 2

B13 - Cylinder 3

B14 - Cylinder 4

B34 - Cylinder 5

The 960 code loops through RAM_21.X and triggers pin B11, B10, B14, B34, B13 (in that order).

For the code modification I was hoping that I could simply change any occurrences of JB RAM_21.0 to JB RAM_21.4, meaning it would loop through the first five pins before starting a new cycle. However, it appears that it may be more complex than originally anticipated, seeing as how there are 2 additional references to RAM_21.5 in the 960 .bin.

When I tested the minimally modified 850 code I did not get spark at any coil except for cylinder 1, which sparked continuously, even before the ignition was turned. The ME7 4 pin coils trigger on a low signal, correct?

Any help on suggested troubleshooting would be excellent.

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Bugger, So close yet so far, Good effort though. Sorry I can't help :( There is only 1 thing I can think of, I really doubt it is this but, the 150ohm are 147ohm and the 47ohm are 46.6ohm. I can't see such I tiny difference causing any problems.

I think simply, razorx, kram, piet, venderbroeck or mercuric (WHERE HAVE YOU GONE!!!) are probably the ones who could help on this

Edited by Avinitlarge

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@Avinitilarge:Maybe my replay is not an addition to this topic.My contribution to the COP part will be minimal until the basics are OK. I consider MAF handling as essential before any further work.

The combined work of Simply Volvo, TMM9 and Piet seems to give good results. And more testing is in progress.

Just step by step. I think that is the way to go.Without a proper MAF handling on high loads any tuning effort is useless. The ECU or ECM needs the real load to calculate properly. This does not mean that you can investigate the COP electronics meanwhile. Just my personal sequence. ;)

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Are you sure the only circuit board difference is the resistors? No additional daughtercards or hardware? Are you looking at an M4.4 V90 ECU for comparison? Or just the software?

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Hussein, did you miss the discussion on circuit and signal condition tracing by RKAM and Avinitlarge pages back?

I just need to bench test my ECU to make sure that the pins are being pulled high like they are supposed to be, but I spent all day making the harness, ECU modifications and code additions and didn't feel like doing much more.

I have been doing work on additional code additions as well, so far I have:

  • Designed boost by gear. I re-purposed 2 of the alternate target load maps into a 1st and 2nd gear boost map. This allows the use of alternate map sets along with boost by gear.
  • Re- purposed the 3rd alternate target load map into an over boost limit map. If the current boost as measured by the MAP sensor is greater than a defined limit the TCV duty cycle map is switched to a custom defineable map, I've chosen to populate mine with all 0's.
  • Added additional top load cells. When load is maxed out but airflow is rising the VE map values will change up to three times to allow for more fuel to be injected. This prevents sacrificing rich conditions at low boost, maxed load conditions so that high boost, maxed load will be an appropriate AFR.

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Nice work TMM9.

Speed density conversion is coming along extremely well. Our CPU has a nice 32 bit math processor which will really speed things up and make things more simple.

Just gotta finish up the last Q number format for converting from moles to kg/hr. Floating point math on a 8 bit CPU that can only do integer operations is not fun! Well actually it's fun just very very abstract.

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Very cool! Do you have any annotated code you would want to share so far? I'd love to have a look.

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The ME7 4 pin coils trigger on a low signal, correct?

They fire on a (steep) negative slope. Before that they need to be charged up by switching to high for a certain (dwell) time, depending on the type and brand of the coil. It's important not to exceed the dwell time too much for too long, as my father can attest to xD bosch coils have a thermal safeguard, aftermarket ones don't.

If only I had some time to learn assembly Oo

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COP, boost by gear, overboost limit map, additional top load cells, speed density conversion.... really cool stuff !

Sometimes it just has to be said: great work guys, it is much appreciated.

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Are you sure the only circuit board difference is the resistors? No additional daughtercards or hardware? Are you looking at an M4.4 V90 ECU for comparison? Or just the software?

I am 99.999% sure its just the missing resistors. Kram and I traced it all, Also had a 960 ECU to compare against too. I went over is a number of times and my findings were the same every time.

Nice work TMM9.

Speed density conversion is coming along extremely well. Our CPU has a nice 32 bit math processor which will really speed things up and make things more simple.

Just gotta finish up the last Q number format for converting from moles to kg/hr. Floating point math on a 8 bit CPU that can only do integer operations is not fun! Well actually it's fun just very very abstract.

WHAT! REALLY! OMFG!! Nice one!!

Edited by Avinitlarge

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Hussein, did you miss the discussion on circuit and signal condition tracing by RKAM and Avinitlarge pages back?

I just need to bench test my ECU to make sure that the pins are being pulled high like they are supposed to be, but I spent all day making the harness, ECU modifications and code additions and didn't feel like doing much more.

I have been doing work on additional code additions as well, so far I have:

  • Designed boost by gear. I re-purposed 2 of the alternate target load maps into a 1st and 2nd gear boost map. This allows the use of alternate map sets along with boost by gear.
  • Re- purposed the 3rd alternate target load map into an over boost limit map. If the current boost as measured by the MAP sensor is greater than a defined limit the TCV duty cycle map is switched to a custom defineable map, I've chosen to populate mine with all 0's.
  • Added additional top load cells. When load is maxed out but airflow is rising the VE map values will change up to three times to allow for more fuel to be injected. This prevents sacrificing rich conditions at low boost, maxed load conditions so that high boost, maxed load will be an appropriate AFR.

Nice work!

Why to use only the alternate target load maps to control boost in 1st and 2nd gear? The alternate TCV maps will be the real alternate maps?

And how it will be for those who run with p-part bin funcionality, i.e. using only TCV maps to control boost and disregarding the target load maps?

That overboost map populated with 0 means it is disabled?

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Very cool! Do you have any annotated code you would want to share so far? I'd love to have a look.

No code yet... Just a VERY long document about speed density in general and more specifically on M4.4.

I will release the document very shortly which goes quite a bit into depth about it.

Its also quite accurate, idle I calcualted to be around 14kg/HR after applying the VE map and high load conditions are similiar in how close. Did some calculation using Husseins logs and with VE applied, the numbers were very accurate.

Edited by Simply Volvo
  • Upvote 1

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