DME printout

notechmike · Jul 2, 2008

I bought my Boxster in March this year (it was first registered 25th May 2006) and when it was in my OPC more recently I asked that they give me print out of the over rev record. The report showed 655 ignitions in range 1 and 44 ignitions in range 2 - I assume this is nothing to worry about?

Further down the report it reported "total distance". This was recorded as 17952.000. Not sure if this is Miles or Km but if the latter then this would equate to 11154 miles. My speedo stated ~11600 miles (I didnt actually check it at the time hence the approx figure). So if units are Km on the DME report then there is just 400 miles that's unexpalined but if the units were Miles then the difference is over 6000 miles. My questions:-

Is the "Total Distance" the distance the car as travelled ie equals speedo distance?
Is the DME units Km or Miles?
What scenarios would expalin the difference?

A fact that may have a bearing on this is that a month earlier I had the PCM swapped out under warranty (single cd was not working). Is this data storred in the PCM or elsewhere? Also shorly after I had the PCM swapped out, the service indicator warned that a service was due sometime in early June although 2 year service should have been due in May had it not been service by the OPC as part of the purchase 2 months earlier. Is the service data storred in the PCM or could this just be a coincidence that the original dealer forgot to reset the system when he serviced it?

Can anyone explain these apparent discrepancies [&:]

Mike

johnk · Jul 2, 2008

your dme results are in km and not mph as you'd figured and from when i have checked cars before there has always been a slight variance from what shows and what it should , i have also noticed on pdi's that the mileage shown compared to the trip is less so this suggests a reset on the inst cluster from fatory for testing cant explain 400 miles though....
your service indicator information is stored in the instrument cluster and is set from pdi but the problem is if the car has been in the workshop say a month later someone may have reset the instrument cluster,

but there was and still is instances where certain areas of electric components ie electric heated seats or something have shut down then this would need a reset which is similar to pdi to reactivate ecu's..

Mark_Bennett · Jul 2, 2008

The range 1 over-revs are nothing to worry about - that is the total number of ignitions (sparks) that have occured when hitting the rev limiter on the way "up" (accelerating). The rev limiter cuts in and prevents you actually over-revving the engine.
The range 2 however is the number that have happened on the way "down" i.e. These are actually above the rev-limit, typically occuring when the driver "wrong-slots" the gear lever in to too-low a gear and releases the clutch, all whilst decelerating. Again it is the number of sparks, so divide by 6 and that's how many revolutions the engine did whilst being over-reved - not many in this case, so probably not from a massivly high revs.

If they did not point out the number of over-revs on range 2, whilst making a sharp intake of breath, shaking the head, and a "tut tut" sound, then they are probably not concerned about it!