hello all,
Should the map sensor read the same as atmospheric pressure when not connected or when engine is running.
Can only get mine to read a max of 90kpa, and it still about 10kpa out from actual pressure readings.
cheers
scott
You need to calibrate the MAP sensor, and ensure it is the correct range
Here is map sensor calibration info from Vemstune help:
| Sensor | Calibration scale |
| 115kPa | 104kPa |
| 250kPa | 250kPa |
| 300kPa | 304kPa |
| 400kPa | 414kPa |
Set this, then if needed, adjust offset to calibrate to known barometric pressure
//Emil
Quote from: [email protected] on December 06, 2009, 09:08:10 PM
Here is map sensor calibration info from Vemstune help:
| Sensor | Calibration scale |
| 115kPa | 104kPa |
| 250kPa | 250kPa |
| 300kPa | 304kPa |
| 400kPa | 414kPa |
Set this, then if needed, adjust offset to calibrate to known barometric pressure
//Emil
Emil, IMHO here is errors.
My experiments and
MPXH6300A datasheet gives another result:
range should be 315.1 and offset 1.1.
I will check rest of datasheets and report!
Gints
Here is the results:
http://www.freescale.com/files/sensors/doc/data_sheet/MPX4115A.pdf
115KPa sensor: offset 10.6 range 111.1
http://www.freescale.com/files/sensors/doc/data_sheet/MPX4250A.pdf
250KPa sensor: offset 10.0 range 250.0
http://www.freescale.com/files/sensors/doc/data_sheet/MPXH6300A.pdf
300KPa sensor: offset 1.1 range 314.5
http://www.freescale.com/files/sensors/doc/data_sheet/MPXH6400A.pdf
400KPa sensor: offset 3.5 range 413.0
All four matches with results on real board by applying 0V and VCC to sensor input.
http://cache.freescale.com/files/sensors/doc/data_sheet/MPX5700.pdf
700KPa sensor: offset -31.1 (negative!) range 777.7
Calculations is done this way:
1) calculated theoretical presures at 0V supply Result is offset.
2)calculated theoretical pressure at Vsupply=Vout
3)subtracted both resulting pressures = range
Gints
Why need to set 315.1 range when the data sheet says 20 to 304 kPa at 3 bar sensor?
Thx
i just installed unit with 250kPa and offset is 10kPa,so its true.
Quote from: z0tya on October 23, 2010, 08:38:36 PM
Why need to set 315.1 range when the data sheet says 20 to 304 kPa at 3 bar sensor?
Thx
Range here is mathematical not physical value. Physically then range is just 304-20=284Kpa.
But ECU calculates MAP value mathematically. datasheet give also line equation for this calculation. My values comes from there and verified on bench test.
Gints