MAP Sensor Reading & Writing to ECU


My project is about reading a MAP sensor on a turbo diesel engine and then writing back the value to ECU which modifies the injection pump rail position which will deliver more fuel under the normal pressure in the manifold at the time…

First test was done in house with another sensor(same one in the car) by using a syringe as my “turbo” to increase the pressure… all went well, next day followed the install and testing, to find out things were not as smooth as the home tests, the car actually performed half as good…

Any ideas are well received ! Thanks.

MAP.ino (434 Bytes)

Your ECU is probably getting upset by the PWM signal that you give it using the analogWrite function. I presume it is expecting a DC voltage that increases as the manifold pressure increases.

That could be the case. Thanks.

Would a diode and a capacitor fix the issue... !? I'm aware this is not an actual conversion from AC to DC...but would still output a much more smoother voltage values to ECU; if that's the case.

I would put original file back in (hopefully you saved it). Then i would do a on vehicle change, your turbo works with manifold pressure and air intake on a calculated value, if you change to much of one then itll try to default map. If its sluggish it sounds like turbo might not be spooling up as per cal values. If you changed values were you able to do a checksum? also your accel pedal is part of cal. could be a timing issue within the program itself, in ms is the norm for injection and pump pressure will change with fuel demand, if rail pressure is exceed itll normally drop. could do a rail test prossibly, lots of factors. Sometimes just opening the trim on the injection will give you the desired result without messing with map tables.