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hi does any body know what the 3 wires on the map sensor are and in what order
also what number pins they go to on the ecu plug
earth
feed
supply to ecu
You should be able to work these out easily with the aid of a multi-meter.
Earth will be common and go to ground all the time.
Feed is a switched voltage that comes on with the key via the main control relay
Process of elimination leaves the line back to the ECM... DMM continuity test function will help you trace this back thru the loom to the ECM
pin a = green earth
pin b = purple feed to ecu
pin c = +5v
earth is fine
measured ohms at 2k between pin b + c with ignition off and got 0.00 so all good
engine idling and probing pins a + b gives a reading of 1.6v (should be +4.3v)
engine at 3000 rpm and probing pins a +b gives a reading of 0.00 (should be +4.1v)
all the above points to a faulty map sensor can anybody confirm what i have checked is correct and is there anything else that could cause the incorrect readings
thats where i found the info to test the map sensor from your previous post
engine idling and probing pins a + b gives a reading of 1.6v (should be +4.3v)
engine at 3000 rpm and probing pins a + b gives a reading of 0.00 (should be +4.1v)
does that seem to point at a dodgy map sensor
thanks
You want to be sure of two things before that sensor is replaced. Firstly, that the ecu is seeing actual "atmospheric" pressure when the engine is off (normally around 101kPa) and then a slight vacuum when running at idle (as an NA engine creates this when breathing).
If you're not seeing atmosphere correctly then the base reading is wrong and the sensor needs replacing