Omni 2.5Bar MAP sensor scaling
 

Hey everyone,

I got a OMNI 2.5Bar MAP sensor, anyone knows how to set the ECUTEK MAP sensor scaling for this one? Thanks!
:thanks::party0030:

ok for 2.5 Bar OMNI MAP sensor ECUTEK scaling in BAR

Manifold Pressure Sensor multiplier in bar per volt. = 0.500
Manifold pressure sensor offset. Value is measured in bar. = 0.100
MAP Sensor voltage max = 5.0v
MAP sensor Voltage min = 0.0v

You may also have to disable CEL codes
P0068
and maybe P0103

Thank you very much! :thanks::thumbup::party0030::cheers:

Bump.

Bringing this thread back from the graveyard since I have this exact sensor that I am wanting to install. And since the Pro ECU and RaceROM software has had several updates since this thread was originally started, are there any changes, tips and tricks or new knowledge and experiences to installing this to replace an OEM MAP sensor. Maybe there is now a way to keep from having to disable any DTC's? I am using the latest versions of both Pro ECU and RaceROM.

Any help would be appreciated. Thanks.

Scaling is math, and math hasn't changed. So nope, everything is exactly the same :)

The DTCs are caused when the sensor exceeds the min or max readings as this indicates a sensor fault (fully open or fully closed). If you setup the min and max values correctly then no DTC will be triggered or need to be cancelled. You can work out where they need to be set based on the offset / multiplier and the voltage of 0 bar and 2.5bar.

P0107/P0108 are MAP Low/High
P0068 MAF/MAP Throttle Position Correlation isn't enabled on Euro ROMs so can't comment (nor US B01C by the looks of it)
P0103 is a MAF code so shouldn't need to do anything with that

In an effort to try to understand and learn all of this as best I can, I have the operating characteristics for the Omni 2.5 bar MAP sensor here:

Attachment 194467

and the Voltage Output/Absolute Pressure Scale for it here:

Attachment 194468

And here I have my MAP sensor values entered into the Pro ECU ROM file maps, labeled:
A) MAP Sensor Scaling - Pressure Offset = 0.100 bar
B) MAP Sensor Scaling - Voltage Multiplier = 0.500 bar/volt
C) MAP Sensor Voltage Max (for the DTC P0108 to activate) = 4.896 volts
D) P0068 MAP Sensor Voltage Maximum (for the DTC P0068 to activate) = 3.30(?) volts
E) MAP Sensor Voltage Min (for the DTC P0107 to activate) = 0.204 volts
F) P0069 MAP Sensor Voltage Minimum (for the DTC P0069 to activate) = 1.25(?) volts

Attachment 194469


Here are my questions:

1) So according to the manufacturer's supplied data, do all of my settings concerning A, B, C, and E look correct?

I realize that I should never get above the maximum voltage of 4.896 to throw a P0108 diagnostic code, nor should I ever get below the minimum voltage of .204 to throw a P0107 diagnostic code with my current or future setup (unless the sensor fails).

If all of those values for A, B, C and E entered above are correct, then:

2) Where would I set the values for D and F if I will be running at an absolute pressure between 20 kPa and 100 kPa for a naturally aspirated application to keep from throwing either a P0068 or P0069 diagnostic code? (I have the values for D and F set at their defaults for the OEM sensor, I have not made any changes to those two values.)

3) Where would I set the values for D and F if I will be running between 20 kPa and 185 kPa for about 12 psig (26.5 psia) of boost to keep from throwing either a P0068 or P0069 diagnostic code? (Again, both are still set to their OEM default values.)

I realize that it can be figured out, but I don't know what values should be plugged into what formula to get the correct results.

4) Other than because @steve99 stated that is what the value should be, where is this value for A) derived from?

5) And for the same reason as stated in question #4 above, where is the value for B) derived from?

Sorry for all the questions, but if I can learn and understand what it is that I'm doing, the better off I'll be in the long run and won't have to ask again.

So the math would be:
2.5 Bar Max - 0.2 Bar Min = 2.3 Bar Range
Voltage Range is 4.692v
So the multiplier is 2.3 / 4.692 = 0.4902 bar/V
Offset is calculated by 0.4902 * Max V (4.896) = 2.4 Bar Therefore 2.5-2.4 = 0.1
P0108 Max should be above any max value in the table so 4.97 would suffice
P0107 Min should be below any min value in the table so 0.1 would suffice

Can't comment on the P0068/69 tables as I don't have them, however so long as the pressure sensor is setup correctly I can't see these being triggered as (a) they don't seem to be actually active DTC codes (P0069 doesn't even appear in my DTC list on EcuTek) and (b) they seem to be within a voltage range that the OEM MAP sensor would see anyway.

Ah, okay I fully understand the math and formulas now.

So in order to figure out the settings for the P0068 and P0069 tables, I would have to compare the OEM sensor default voltage settings to their equivalent bar pressure values as if the OEM sensor was still in use in the system, and then match those bar pressure results to the new Omni sensor voltages at those same pressures. That will work for both the P0068 and P0069 settings in a naturally aspirated application, but in a 12 psig boosted application, I will still have to figure out the new P0068 value. The P0069 value can most likely stay where I determine it needs to be for the new sensor as it will never see boost.

I did also notice that P0069 isn't even given as a DTC on/off option in my set of ProECU DTC maps as well, so this setting probably won't even be a concern.

I guess I have two choices on what to do concerning the P0068 setting for a 12 psig boosted application:

a) Experiment with the voltage/pressure setpoint to find where it can safely be set to, so that it does not trip the check engine light, which will be slightly above the voltage equivalent of 185 kPa for the Omni sensor (about 3.5 volts),

or

b) Simply un-tick that specific fault code from the DTC map in the software, as @steve99 originally suggested.

It all makes sense to me now.

So where can I find an output voltage versus absolute pressure table for the OEM sensor? I suppose using geometry, I can make one.

So here are the settings I'm going with for this new Omni MAP sensor for the time being. Changes from the first round are highlighted in yellow. The values for A, B, C and E should be exact, and I've decided to temporarily leave the values for D and F at the OEM defaults for now (circled in red) and see how that operates in naturally aspirated configuration. I'll change them later if I decide I need to or simply untick the P0068 from the DTC map. However, I highly doubt there will be an issue until I am boosted. I'll cross that bridge when I burn it.:

A) MAP Sensor Scaling - Pressure Offset = 0.1000 bar
B) MAP Sensor Scaling - Voltage Multiplier = 0.4902 bar/volt
C) MAP Sensor Voltage Max (for the DTC P0108 to activate) = 4.966 volts
D) P0068 MAP Sensor Voltage Maximum (for the DTC P0068 to activate) = 3.30 volts
E) MAP Sensor Voltage Min (for the DTC P0107 to activate) = 0.133 volts
F) P0069 MAP Sensor Voltage Minimum (for the DTC P0069 to activate) = 1.25 volts

Attachment 194485

Thank you @Kodename47 for your generosity and teaching skills.