MAP Scaling Options ?

[kidturbo]

Has anyone figured out how to add a table for MAP scaling / calibration in LBZ/LMM ?

Looking for a way to use a 4 or 5 bar MAP.. Basically to get a true reading on digital gauges after BARO subtraction from MAP. 23PSI don't cut it..

Tks

-KT

[kidturbo]

Nobody?

I've heard of custom tables being added by certain tuners. Looking for some insight on the options.

[Chavez91]

http://www.duramaxdiesels.com/forum/showthread.php?t=11144

[kidturbo]

Thanks for that link. I found someone with the .cax file to modify it.

Here is the marine display layout for LBZ/LMM.

19328

[kidturbo]

OK after passing this off to a couple very well qualified tuners, it remains unresolved. Yes it's been done in LLY and LML, but I can't find where anyone has done it on an LMM.. So again I ask for help from of anyone who knows their way around that bin.

[GMPX]

So you are looking for the equivalent of this LLY Table?

Boost Sensor Scaling (PSI)
0.00 4.829302
0.16 6.352198
0.31 7.861497
0.47 9.368529
0.63 10.877828
0.78 12.387126
0.94 13.894159
1.09 15.417055
1.25 16.926353
1.41 18.433385
1.56 19.942684
1.72 21.451983
1.88 22.959015
2.03 24.481911
2.19 25.991210
2.34 27.498242
2.50 29.007540
2.66 30.516839
2.81 32.023871
2.97 33.546767
3.13 35.056066
3.28 36.563098
3.44 38.072397
3.59 39.581695
3.75 41.088728
3.91 42.611624
4.06 44.120922
4.22 45.627955
4.38 47.137253
4.53 48.646552
4.69 50.153584
4.84 51.676480
5.00 53.185779

[kidturbo]

Exactly.. But in a cax file so I can integrate it into regular or custom DSP5 OS builds.

IE: I am calculating boost values off of MAP-BARO pressure pids for the display. Current max value is like 24PSI.

[GMPX]

It might be a scantool PID limit and not the sensor itself. Does anyone know what the standard LBZ/LMM Map sensor will read up to?
It could be the PID you are using is limited to 255 kPa (37 PSI), adjusting for ambient (37 PSI - 14.5 PSI) gives 'about' the 24 PSI limit you see.

[kidturbo]

I believe factory MAP is listed as a 3 or 3.3bar. I have scaled the ECM with a POTs input on a bench output up to 37psi. Which just so happens to equal,, 255kpa...

akdjflajdlkfadhahdhsdffhja :throw:

Pid: OB - Intake Manifold Absolute Pressure {SAE.MAP}

Units: kPa
Range: 0..255 kPa

Units: inHg
Range: 0..36 psi

Well that was a wasted exercise.... Not like I didn't have that info in a file on my desktop.. I only considered the EFIlive limit of 400kpa, and never guessed that SAE.MAP values would be lower due to the Vac side readings.

Any GM PIDs like Boost2DMA that I've missed read full boost range?

[GMPX]

Off the top of my head I don't know on that ECM, best bet would be to validate all PID's and look over the list of boost PID's to see if any of them extend past 255 kPa. GM do have PID's that do but it is a matter of if the ECM supports it.

[kidturbo]

Thanks Ross.

I found post on other forums about {GM.BOOST2_DMA} reading up to 400kpa or 58psi uncorrected boost. Backed up with the LBZ log below showing 46.8psi / 323kpa [just under 3.3bar] or actual sensor value.

PRI CAPTION DESCRIPTION VALUE UNITS MIN AVG MAX PARAMETER SYSTEM

1 BOOST2_DMA Turbo Boost Pressure 14.7 PSI 14.7 25.5 46.8 GM.BOOST2_DMA Diesel LBZ/LMM



I could quickly verify this on the bench, but my V2 shipped out for repair today.. However it stands to reason our LBZ above or LMM OS can read up to 400kpa / 58psi / 4bar uncorrected, or about 40psi corrected boost on that pid. Better than 24 for sure... Which still leaves a little resolution for using a 5bar MAP if could be scaled to match.

Sound correct?

[kidturbo]

Ok my V2 is back in hand. Many thanks to the SoCal crew for a fast turn around..

I scaled out both known LMM MAP sensor "PID's" voltage slopes using a pots on my bench setup. Which only leads to more confusion...

As suspected the OBD-II or SAE.MAP pid tops out at 37psi/255kpa.
The GM.Boost_DMA pid tops out at 53.1psi/366kpa.
19389

Easy enough, except one of these two PIDs is wrong... They don't track together, anywhere up our scale.
19388

Here is a bottom to top to bottom sweep for your review. You can see the ECM continues report the GM.BOOST_DMA and GM.MAP2 up to 53.1 psi and 366 kpa after the SAE.PID values end at 37. But they don't match below 37...
19387

According to the "LLY MAP" scale Ross posted previously, the SAE.MAP pid is wrong. I don't have a MAP sensor handy to verify this, but here is the voltage comparison as I tested on the MAP signal pin of the ECM.
19386

So assuming GM.BOOST_DMA is correct, all OBD-II based scan tools are wrong... Heads up world, I guess.

If our factory LMM MAP sensor is a 3.3bar, that equals 330kpa max. Slightly under our current GM PID upper limit. While EFIlive boost related table limits are 4bar or 400kpa.

Leaving a possible 70kpa or 10psi of resolution that could be gained using a 4bar map. And leaving me unsure how the output values would look if we "could" rescale the MAP voltage in the ECM to 4, 5, or even 10 bar sensors..

Please digest this data and let me know your thoughts.

Tks

[kidturbo]

Figured it out.

MAP Scaling "how to" and cax files available at: http://www.duramaxdiesels.com/forum/showthread.php?t=71271

-K