setting for a 3 BAR MAp sensor

tyrone27 · Post by **tyrone27** » Tue Feb 21, 2006 4:55 am

Does anyone have the setting for a GM 3 BAR map sensor? I'm going to be running a GM MAP instead of the 2.5 BAR one.

T3Bunny · Post by **T3Bunny** » Wed Feb 22, 2006 9:37 pm

I was JUST about to post a simular question Mr. D!

Okay it SEEMS that MT can be dealt with the 3-bar simply by selesting the differant sensor. Is this correct guys?

I have a bad feeling though the code has to also be hacked... Since the most I have delved into the code is using Easy Therm to fix sensor values, I am a little bit at a loss here.

I am seeing this inforation, http://www.megasquirt.info/v22manual/3bar.htm but we need to impliment this easily and quickly into the extra code. It SEEMS to me like this is the same thing we are doing with Easy Therm for the coolant and IAT sensors? It would be nice to add such a feature into Easy Therm...

BTW, its a V2.2 we are messing with running MS-1 and, well, whatever code is in it at the moment! It may change any time....

T3Bunny · Post by **T3Bunny** » Fri Feb 24, 2006 12:26 am

Okay I admit thats pretty trick! Seems all that has to be done now is to input new values and tweaks into MT, then reset the .ini. No more messing around in the code! I must have been sleeping in class again.

I have a feeling though the vaccume/boost gauge is going to be broken... But we shall see soon enough.

John L. · Post by **John L.** » Fri Feb 24, 2006 12:46 am

OR.......

you could just go into car1/mtCfg/settings.ini and change this:

Code: Select all

#group MAP_SENSOR "Map Sensor Type"
   #unset MPX4115      "MPX4115 - 115 kPa, Usually only on v1.01 boards"
   #  set MPX4250      "MPX4250 - 250 kPa, Default MAP sensor since v2.2 hardware"
   ;obsolete GM300KPa  "GM 3.0 BAR - 300 kPa"
   ; Incorrect info from http://www.aquamist.co.uk/sl/plist/pics/mapm/mapm.html
   ;   Correct info from http://www.not2fast.com/electronics/component_docs/MAP_12223861.pdf
   ; Use MPXH6300A instead of GM300KPa, they have identical specifications.
   #unset MPXH6300A    "MPXH6300 - 300 kPa"   ; http://www.freescale.com/files/sensors/doc/data_sheet/MPXH6300A.pdf
   #unset MPXH6400A    "MPXH6400 - 400 kPa"   ; http://www.freescale.com/files/sensors/doc/data_sheet/MPXH6400A.pdf
#endgroup

to this:

Code: Select all

#group MAP_SENSOR "Map Sensor Type"
   #unset MPX4115      "MPX4115 - 115 kPa, Usually only on v1.01 boards"
   #unset MPX4250      "MPX4250 - 250 kPa, Default MAP sensor since v2.2 hardware"
   ;obsolete GM300KPa  "GM 3.0 BAR - 300 kPa"
   ; Incorrect info from http://www.aquamist.co.uk/sl/plist/pics/mapm/mapm.html
   ;   Correct info from http://www.not2fast.com/electronics/component_docs/MAP_12223861.pdf
   ; Use MPXH6300A instead of GM300KPa, they have identical specifications.
   #  set MPXH6300A    "MPXH6300 - 300 kPa"   ; http://www.freescale.com/files/sensors/doc/data_sheet/MPXH6300A.pdf
   #unset MPXH6400A    "MPXH6400 - 400 kPa"   ; http://www.freescale.com/files/sensors/doc/data_sheet/MPXH6400A.pdf
#endgroup

Note that for the GM sensor you set it to the MPXH6300A as noted in the code there, this is because to my knowledge the GM MAP is simply a Motorola MPXH6300A chip inside a case with a GM part number on it. Come on, you guys didn't think GM REALLY made MAP sensors did you? Only the case LOL.....

Oh, and the 6300A is way cheaper....in fact you could just get the 6400A and be good to 4 bar or 45 psi boost, haha, that's what I've got. Just need to be a little creative with the mounting and hose connection, as it's a surface mount chip, and a little delicate, but great for in case installation.

T3Bunny · Post by **T3Bunny** » Fri Feb 24, 2006 1:10 am

John L. wrote:Come on, you guys didn't think GM REALLY made MAP sensors did you? Only the case LOL.....

I had heard rumors! Well Tyrone27 had a 3bar GM from his previous Electromotive install he tossed my way, so sensor cost wasn't a factor in it. It was just time to poke at some new toys!

But even with the above, I think you still need to make the tweaks for the sensor in "code config" inside MT. It does read differant voltages at the same kpa points, so if the internal cpu code isn't recompiled for the new lookup tables, you still have to correct it somehow. The MT .ini there is only for fixing how MT itself translates what the ecu is sending it.

Simular to whats done using EasyTherm and recompiling the code to run mixed, or compleatly differant temputure sensors. The differance here is its just a correction factor being burned in through the MT interface. Confusing sometimes! And I likely may still be confused! Oh well, I am definatly having fun though!

John L. · Post by **John L.** » Fri Feb 24, 2006 1:43 am

That may be. I didn't know that. Well, I hope someone can come in and back that up, cause I've got a 4 bar and not sure if it's going to read right...just using the 2.5 bar for now.

John L. · Post by **John L.** » Sun Feb 26, 2006 8:42 pm

Does anyone else have comments? Just wanted to be certain that I will have to do this to run the 4 bar sensor, and what process I'm supposed to use to get the calibration values is I have to do it that way?

tyrone27 · Post by **tyrone27** » Tue Mar 07, 2006 7:54 pm

bump info needed

MiseryQ · Post by **MiseryQ** » Tue Mar 07, 2006 8:17 pm

Not quite sure if this helps any.

I DL'd the 1bar files from here, do a search I believe the 3bar files have also been posted.

I changed the header of the baro & kpa factor files and renamed them to to what the compiler expected, I replaced the 115kpa baro sensor ini files since they were'nt used.

Compiled the MSNS-e and dropped the "hacked" baro & kpa files in the MegaTune folder and all works.

T3Bunny · Post by **T3Bunny** » Wed Mar 08, 2006 1:08 am

Okay I have it from a good reliable source running a 3 bar that ALL that needs to be done is to make adjustments to the cablibration inside MT. No code changes needed this way. This IS in referance to MS-1. He mentioned that the boost guage in MT will not read right, but I think that will be fixed by selecting the 3bar sensor setting in the .ini file.

I will let you guys know as soon as I beat all the issues out of this car!!! I was FINALLY ready to fire up the latest project, and the starter wiring lost all its smoke.

John L. · Post by **John L.** » Wed Mar 08, 2006 7:41 pm

That is the conclusion I keep leaning onto also, for the Motorola sensors, the difference in output has been accounted for in MT. I will also try it and see if the readings agree with my boost gauge, as long as it's close I'd call it good, as you'll be tuning with VE anyway. It may be a few days to a few weeks before I have the 4 bar setup though.

There is a setting to change in the MT runtime screen as well as the .ini, BTW.

shaodome · Post by **shaodome** » Thu Mar 09, 2006 8:41 am

I am using an RS Autosport 3bar map and when switching over, the car ran fine from the original 2.2 hardware, but I noticed with the car off, the KPA @ atmosphere was 10 lower. It would normally read around 98kPa (sea level), no its at 87 on the MT gauge.

Is this to be expected?

T3Bunny · Post by **T3Bunny** » Thu Mar 09, 2006 9:18 am

No something is wrong there. It needs to read correctly at atmoshere. In fact thats the quickest way to check and make sure its calibrated correctly.

tyrone27 · Post by **tyrone27** » Tue Mar 14, 2006 6:14 pm

bump any more info in thos

84ae · Post by **84ae** » Wed Mar 15, 2006 6:00 am

Yeah, what about megatune's limit of 255 for kpa values? how do you get around that with the 3-bar or bigger map sensor?

Post by **jsmcortina** » Wed Mar 15, 2006 6:27 am

Here's what's going on.
The MAP sensor outputs a voltage between 0 and 5v which corresponds to something near 0kpa up to full pressure.

MS then reads this voltage on the A/D port and converts it into a number 0-255.

It then uses a lookup table to convert this into pressure.

With the MPX4250AP this is pretty close to 1:1

With >2.55bar we've got a problem as we would need a number bigger than 255. So instead we changed the scale so that 255 no longer means 2.55bar, but it means 3bar or 4bar. ie. an internal pressure number 255 means full pressure.

The 3bar and 4bar sensors need different scaling, so you tell the Megasquirt this scaling via the MAP sensors dialogue in Megatune.

Secondly you have to tell Megatune that when it sees a pressure number it has to be scaled differently - this is the change in settings.ini.

With the car off all sensors should correctly display atmospheric pressure. That 10kpa difference is too much. If you scaling factors are entered correctly then there may be a code issue.
I guess you can always tune around it anyway, but it makes sense to start somewhere close.

James

shaodome · Post by **shaodome** » Tue Apr 04, 2006 6:47 pm

In megatune, it says to use a Baro Correction factor of 28% and a Kpa Correction of 28% for the 3bar sensor....

I have it on my stim right now with just the INI adjusted and I changed the map in megatune to the 300kPa. Correction factors are still 0. When I ramp up the squirt to full WOT load and peg it in the top right corner of the VE table....its about 85% duty cycle.

If I change the correction values to the suggested 28%s my duty cycle jumps WELL over 115%

Help?

Forrest · Post by **Forrest** » Thu Jul 06, 2006 10:09 pm

I'm sorry guys, I'm still confused...
I am running MSSE 29q2 with the Rs-autosport 3bar sensor. After changing the settings.ini the gauge output is correct. But is this just the output and my board is internally using the wrong values?

http://www.megamanual.com/v22manual/3bar.htm
The Megasquirt.info page says MS-I code needs to be recompiled. It says "Check the MSSE page for updates" (not sure which updates they mean)

So, the question is, does MSSE firmware need to be recompiled for the 3bar sensor?

T3Bunny · Post by **T3Bunny** » Thu Jul 06, 2006 10:21 pm

Not anymore. There are now correction factors inside MegaTune that will rescale the outputs so recompiling the code is no longer neccisary. Look under Code Config and then Map Sensor Settings.

Post by **jsmcortina** » Fri Jul 07, 2006 1:46 am

The settings has moved - it is now on the Contants page so you can choose 115k, 255k, 300k, 400k sensors on one drop down.

If you have a mismatch you should also see "Map sensor warning" on the menu which explains some of your error.

James