Engine over-rev warnings – advice, please!

[sidicks]

Engine over-rev warnings – advice, please!

My car is currently at the OPC going through its 111-point check to obtain a new warranty. As part of the checks, the OPC has identified a few warnings in the level 1-5 range (I don’t yet have the details) and they claim that in order to obtain the warranty they need to remove the oil filter and take some pictures to send to Porsche (to check the presence of swarf etc) to obtain approval for the warranty to be granted.

Apparently these over revs occurred fairly recently, hence they have to be investigated, and obviously the labour cost for doing so is not covered by warranty or the cost of the check.

So, key questions:
• Has anyone had to have this done?
• In terms of the over revs, what detail is available?
o I’m 100% sure at no point have I changed down into the wrong gear which would cause an over-rev (which I understand is the worst sort) and although I drive the car reasonably hard, I don’t recall bumping into the limiter recently either, albeit that this should be less concerning as the limiter should be designed to cut in prior to any damage being caused!
o I’m therefore hoping that this is purely precautionary. Do the over-revs have a date / time listed, or is it purely an ‘hours of use’ measure? The car was with the OPC a few months ago for some warranty work, so I’d be very keen to understand if this happened when the car was with them!

Thanks

Sidicks

[anonymous-user]

The DME report gives over revs in ranges 1 -6 for a Cayman, I think it is different for a 911.
The running hour that they occured in in aslo logged, so it should be easy to identify when someone bumped the limiter ..... or beyond.

[SFO]

but how do you correlate the 'running hour' to the actual time and date an event happened?

[Sunnysidebb]

Is your car tuned. Some tunes raise the rev limit a small amount but the alarm limit probably will not have been raised, so every time you go past the alarm limit but not the new rev limit it could log an over rev event??
Its is possible depending on your tune, but not that likely.
Frank

[anonymous-user]

Well, when I say easy to identify, I mean if the car has a total of 340 running hours and the DME has errors logged at 338hrs , the OP said they had been logged recently, perhaps her indoors took the car shopping and missed a downshift last weekend .

Not sure how you could tell if the errors occurred at 127hrs etc.

[GT Glee]

You unfortunately won't have a time log of overrev events but as already said the engine operating hour when the last overrev event occured. From this you can calculate the mileage of the event (using average mph), then look at the mileage as recorded on the OPC invoice/report.

[Ian_UK1]

These are the rpm ranges for a gen-1 997

Range 1: 7300-7500rpm
Range 2: 7500-7700
Range 3: 7700-7900
Range 4: 7900-8400
Range 5: 8400-9500
Range 6: 9500-11000

Range 1 'overrevs' can be caused just by hitting the limiter on the way up, so the number can be very large with no harm whatsoever. I believe an occasional Range 2 can happen the same way so OPC's tend not to care at all about R1 and R2. Same with R3 but I'm assuming you (or a previous owner) will need to have mistimed a change to push the rpms that high. R4 seems to divide opinion amongst OPCs from what I've read - some don't seem to bother, others want oil analysis.

R5 ignitions have the potential to do serious damage so full analysis will always be required and, again from what I've read, warranty may be denied.

R6 will likely have detonated your engine anyway, so it's a moot point!

Hope the info's of some use.

Edited by Ian_UK1 on Tuesday 22 February 16:10

[nsm3]

You have had this car from new if I am correct?

I think they are taking the p155 unless you secretly "know" you have thrown it into 2nd at 90mph recently?

[Ian_UK1]

Just to add to my post above, I've also seen 1 car that had the same (large) number in all the 6 ranges (may have been 65536, not certain). This turned-out to be a faulty chip - the one that records the overrevs - so the car's engine may or may not have been 'buzzed'. If you're seeing identical large numbers then this is possibly the problem, not an abused motor.

Edited by Ian_UK1 on Tuesday 22 February 16:19

[sidicks]

Thanks for the comments so far, in response:

- The car is standard hence eligible for the OPC warranty

- I have owned the car from new, so I can’t blame any previous owners, and my wife rarely drives it (for obvious reasons!), and certainly not recently!!

- I can accept that there might be one or two range 1 or 2 records, but would be extremely surprised to hear about any others – I’m 99% convinced that if any appear ten they aren’t down to me and I would want further investigation.

In terms of using the average speed to calculate when the incidences occur, I assume that is also held on the chip, rather than being calculated from the on-board computer which will probably have been reset since the last service??

Sidicks

[Ian_UK1]

sidicks said:

Thanks for the comments so far, in response:

- The car is standard hence eligible for the OPC warranty

- I have owned the car from new, so I can’t blame any previous owners, and my wife rarely drives it (for obvious reasons!), and certainly not recently!!

- I can accept that there might be one or two range 1 or 2 records, but would be extremely surprised to hear about any others – I’m 99% convinced that if any appear ten they aren’t down to me and I would want further investigation.

In terms of using the average speed to calculate when the incidences occur, I assume that is also held on the chip, rather than being calculated from the on-board computer which will probably have been reset since the last service??

Sidicks

Yes the 'time' of the last overrev incident (in numbers of operating hours from new) is held on the chip. It's only the time of the last incident that is stored, however, and any new incident overwrites the time stamp with a new value so it's unfortunately of very limited use.

[GT Glee]

Ian_UK1 said:

These are the rpm ranges for a gen-1 997

Range 1: 7300-7500rpm
Range 2: 7500-7700
Range 3: 7700-7900
Range 4: 7900-8400
Range 5: 8400-9500
Range 6: 9500-11000

Range 1 'overrevs' can be caused just by hitting the limiter on the way up, so the number can be very large with no harm whatsoever. I believe an occasional Range 2 can happen the same way so OPC's tend not to care at all about R1 and R2. Same with R3 but I'm assuming you (or a previous owner) will need to have mistimed a change to push the rpms that high. R4 seems to divide opinion amongst OPCs from what I've read - some don't seem to bother, others want oil analysis.

R5 ignitions have the potential to do serious damage so full analysis will always be required and, again from what I've read, warranty may be denied.

R6 will likely have detonated your engine anyway, so it's a moot point!

Hope the info's of some use.

Edited by Ian_UK1 on Tuesday 22 February 16:10

Are all ranges mechanical overrev? Or are Range 1 ignitions limiter only?

On earlier ECUs you get Type 1 and Type 2. 1 is for limiter ignitions and 2 for mechanically revving beyond the limiter.

[Soovy]

sidicks said:

Thanks for the comments so far, in response:

- The car is standard hence eligible for the OPC warranty

- I have owned the car from new, so I can’t blame any previous owners, and my wife rarely drives it (for obvious reasons!), and certainly not recently!!

- I can accept that there might be one or two range 1 or 2 records, but would be extremely surprised to hear about any others – I’m 99% convinced that if any appear ten they aren’t down to me and I would want further investigation.

In terms of using the average speed to calculate when the incidences occur, I assume that is also held on the chip, rather than being calculated from the on-board computer which will probably have been reset since the last service??

Sidicks

They will get the number of ignitions in each range.

1 and 2 are no problem - rev limiter on the way up.

3+ means mechanical over revs (i.e. 5th to 2nd or something!)

If you have 3+ on your engine, then if you dind't do them..................

[Ian_UK1]

GT Glee said:

Are all ranges mechanical overrev? Or are Range 1 ignitions limiter only?

On earlier ECUs you get Type 1 and Type 2. 1 is for limiter ignitions and 2 for mechanically revving beyond the limiter.

The numbers stored for all ranges are numbers of ignitions (i.e. 3 per revolution for a 6 cylinder motor) that have occurred in total whilst the engine speed was within that range. What caused the engine to be there is irrelevant from the point of view of the stored data.

In practice the 'soft' limiter can allow a bit of leeway on the way up (possibly as far as R2) but it would typically take a mechanical overrev to go higher. Bear in mind that to get to R3 you have to go through R2 and R1 twice - so R1 and R2 can be caused both by normal operation and mechanical overrev.

Edited by Ian_UK1 on Tuesday 22 February 16:30

[GT Glee]

sidicks said:

Thanks for the comments so far, in response:

In terms of using the average speed to calculate when the incidences occur, I assume that is also held on the chip, rather than being calculated from the on-board computer which will probably have been reset since the last service??

Sidicks

Yes you have total operating hours, and operating hours at the overrev event (I presume stored separately for Range 1 to 6 on you later ECU). I would calc average mph from the current mileage and operating hours (and out of interest would compare to the OBC).

[Ian_UK1]

GT Glee said:

I presume stored separately for Range 1 to 6 on you later ECU

Unfortunately not - one timestamp only IIRC


Edit: - Sorry, wrong about this, there is a timestamp per range.

Edited by Ian_UK1 on Tuesday 22 February 17:13

[Davey S2]

Sorry for the numpty question but other than say being at full revs in 3rd and accidentally going into 2nd rather than 4th how can you over rev a car while changing up?

Surely thats the whole point of having a rev limiter so if you occassionally nudge into it while changing up it wont do any damage?

[Soovy]

bloke on another Pork forum said:

I checked out the DME


Range 3
543 ignitions at 269.9 H

Range 4
257 ignitions at 269.9 H

Range 5
92 ignitions at 269.9 H

Range 6
o


Total operating hours =361

By way of example, this means that someone missed a gear in this car 100 hours ago, and it over revved. Notice how the number of ignitions is lower the higher the revs - i.e the engine was "buzzed"

[edition]

Whats the limiter set to on a standard car?

[Soovy]

Davey S2 said:

Sorry for the numpty question but other than say being at full revs in 3rd and accidentally going into 2nd rather than 4th how can you over rev a car while changing up?

Surely thats the whole point of having a rev limiter so if you occassionally nudge into it while changing up it wont do any damage?

That's the point.

RR1 and RR2 are the limiter. R3+ means a fk up.