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  • As MEMS3 is EOBD compliant, the error code messages ought to be standardized - which should mean that there is a complete list of EOBD fault codes in French/ Spanish/ German that could be used to provide relevant translations... :)
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  • There are quite a few irrelevant data sets in the ISO mode for functions/ parameters that MG Rover did not implement on MEMS 3 - like ambient temperature, fuel temperature etc. Therefore, the numbers for these are largely spurious.

    There is little spurious data in the BMW proprietary mode - although the inlet cam position data is irrelevant for non-VVC engines (hence the "?"). But not sure why there are still ambient temperature and fuel temperature outputs? Unless this is an error, or this is a hang-over from the ECU's original development??? Perhaps Philip can comment?

    The data probably provides a starting point for knowing what normal values might be - although whether this car has a problem or not I don't know! LOL It runs very well, and there are no reported errors, so hopefully all is well. :)

    I can get the same data from an MGZS 120, and in the future from a MGZR 105 (MEMS3).

    I can also obtain MEMS1.9 data from my two MGFs :) The data you get from MEMS1.9 will be interesting to compare as it is quite an interesting ECU (as the fuel/ignition adaption post shows) :)
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  • BMW proprietary mode
    VariablemeanSD
    Throttle angle (degrees)4.000.00
    Throttle potentiometer voltage (V)0.600.00
    Throttle valve statusClosed/ Open
    Ignition switchOn
    Aircon Fan RequestRequested
    Aircon Clutch RequestNot requested
    Drive/ Neutral statusNeutral
    Security InputHigh/ Low
    Aircon switchOff/ On
    Alternate Aircon Fan RequestRequested
    Intake manifold pressure (V)32.540.50
    Stepper position (steps)18.940.12
    Engine speed (RPM)776.1221.65
    Idle error (RPM)5.2115.89
    Vehicle speed (KPH)0.000.00
    Coolant temperature (Celcius)82.000.00
    Oil temperature (Celcius)76.280.41
    Intake air temperature (Celcius)39.000.00
    Ambient air temperature (Celcius)-40.000.00
    Fuel temperature (Celcius)-40.000.00
    Battery Voltage (V)14.220.03
    Crankshaft signalokay
    Cahaft signalokay
    High speed sync losssync loss
    Cam input historyinput was high
    Cam position (degrees)0.000.00
    Crank position (degrees)366.97198.02
    Coil 1 Charging Time (usec)2827.000.00
    Coil 2 Charging Time (usec)3000.000.00
    Injector Firing Interval (degrees)720.000.00
    Injector pulsewidth (msec)2.720.06
    Injector Deadtime (msec)0.500.00
    Fueling feedback correction bank 1 (%)1.040.02
    Oxygen sensor oltage bank 1 (V)0.600.18
    Fueling feedback correction bank 2 (%)1.020.00
    Oxygen sensor oltage bank 2 (V)0.760.01
    Oxygen sensor statuse bank 1active
    Oxygen sensor statuse bank 2inactive
    Requested cam period?
    Measured cam period?
    Inlet valve open angle?
    Inlet valve closed angle?
    Closed loop idle control statusactive
    Idle speed control test statusNot active
    Throttle statusClosed
    Engine cranking statusNot cranking
    Engine started statusStarted
    Engine stopped statusNot stopped
    Oerrun fuel cutoff statusNot active
    High speed fuel cutoff statusNot active
    Fuel pumpOn
    MIL LampOff
    Aircon ClutchOff/ On
    Radiator FanOff/ On
    Auxiliary FanOff
    o2 Sensor HeaterOff/ On
    Engine FanOff/ on
    Cruise DisableOff
    Purge valve duty cycle (%)0.070.00
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  • I have also captured about a minutes worth of warm idle data from my 2001 Freelander (1.8S) with MEMS3. This data I have averaged, and calculated the standard deviation. I have done this for both ISO and BMW proprietary modes (they're slightly different).

    ISO MEMS3:
    VariablemeanSD
    Ignitionon
    Control unit statusenabled
    Coolant temperature (°C)85.260.55
    Oil temperature (°C)79.220.18
    Intake air temperature (°C)40.400.13
    Ambient air temperature (°C)-40.100.00
    Intake manifold pressure (kPa)33.060.23
    Torque conv clutch pos sens voltage0.590.00
    Engine speed (rpm)773.8112.34
    Battery voltage (V)13.970.12
    Vehicle speed (kph)0.000.00
    Vehicle motionnot moving
    Adaption of throttle valve act motor29.000.00
    Idle stabilisationcompleted
    Idle controlactive
    Idle conditionsok
    Desired idle speed (rpm)775.000.00
    Throttlealve positionclosed
    Throttle valve servo motor (steps)37.350.61
    Idle speed control-3.5817.16
    Injection time cylinder 1 (msec)2.690.05
    Injection time cylinder 2 (msec)2.690.05
    Injection time cylinder 3 (msec)2.690.05
    Injection time cylinder 4 (msec)2.690.05
    Injection time correction (msec)0.500.00
    Additive mixture correction IV error101.89%2.40%
    o2 sensor voltage bank 1 sensor 1 (V)0.430.23
    o2 sensor voltage bank 1 sensor 2 (V)0.720.01
    Lambda controlactive
    Mixturelean/rich
    o2 sensor readyready
    Lambda probe functionnormal
    o2 sensor heater (bank 1 sensor 1)100.00%0.00%
    Crankshaft signaldetected
    Ignition angle (degrees)13.490.86
    Ignition angle correction (degrees)0.000.00
    Fuel evap controlalve duty cycle7.00%0.00%
    Fuel pump relayon
    Exhaust gas relevant misfire total0.00%0.00%
    Misfiring Cylinder 10.00%0.00%
    Misfiring Cylinder 20.00%0.00%
    Misfiring Cylinder 30.00%0.00%
    Misfiring Cylinder 40.00%0.00%
    Power steering pressure sensor14776.702.40
    Generator load0.590.01
    Aircon requestoff
    Airconap temp (°C)-273.20
    Aircon compressor releaseinactive
    Radiator fan relay 1inactive
    Radiator fan relay 2inactive
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  • Here are the Lambda logged data from a MEMS3 equipped Freelander 1.8 K-series. The engine was pre-warmed, but switched off for about 10 minutes to allow the exhaust temperature to cool.

    This appears to be completely normal operation. There are two lines of data - the pre-catalyst sensor and the post catalyst sensor.

    Both traces start at the same point when the ignition is switched on, and then diverge as the exhaust warms up. The Lambda sensor has an operating temperature of 300C - which explains the flat trace before the signal starts to oscillate (blue line). The post oxygen Lambda tends not to oscillate - which is normal. If it were to oscillate in rhythm with the pre-cat sensor, then the catalyst has failed...

    I recorded these traces with just two channels - for both the Lambda sensor. The re-fresh rate is then somewhere between 6-8 times per second. If you have more than this open, the re-fresh rate plummets - add engine speed or oil temperature for example, and the re-fresh rate drops to 3-4 times per second. Open all channels for recording, and the refresh rate appears to be about 3.5 seconds! Less is more if you want some fidelity of the Lambda trace (and arguably, you would :))

    Note that I did the recording both at natural idle and at a fast idle of between 2,500-3,500 rpm. This replicates the MoT conditions. The cold idle will have a lower exhaust temperature, the fast idle a much higher exhaust temperature - and it is under the latter condition that the Lambda will likely give the most reliable data.

    What struck me is that the switching frequency varied so much between natural and fast idles. The ECU feedback cycle is slow when the idle speed is low - just once evry 3 seconds or so (approx. 0.3Hz), but increases significantly with a fast idle to once a second (approx. 1.0Hz). I don't think I've ever seen this on a trace published online - so was quite fascinating to me.



    This data telemetry would be very helpful in diagnosing MoT emissions fails - if you repeat the above with an oil temperature of at least 70C, natural and fast idle (2,500-3,000 rpm), you will see whether the Lambda is behaving itself. An old Lambda will have a lower mean signal (lower peak, lower minimum) and may also oscillate at a lower frequency. Old Lambdas work better at warmer temperatures - so at idle there may be a poor signal that is recovered by fast idle (hotter exhaust gas temperature, and therefore a hotter Lambda sensor). A failed catalyst will be picked up on MEMS 3 through the post cat signal that will oscillate with the pre-cat sensor.

    Hope this is of interest! :)
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  • You'll just need the code for the immobilizer - the rest ought to be plug and play :)
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  • My PC appears to be struggling with the .ods file for some reason, but the PDF looks good.

    For emissions-related functions (Lambda etc) - then it would be good to correlate these figures with the last MoT emissions data. My guess is that one of the commonest reasons why folks will be using the MEMS data download will be to work out why their car has failed its MoT!

    Therefore, it would be good to collate both known "good" data and known "bad" data.

    The former is a big enough project, so let's start with that, concentrating on the "good" data :)
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  • Note to self - much easier/simpler to convert millisecond time base to hh:mm:ss using this instead: =TEXT(A1/86400000,"hh:mm:ss.000") - doh!
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