BED997

I'm a noobie at this, so please bear with me. Just had a car go through a PPI inspection. Car has 3 months of CPO left on the clock. The following came back:

Range 1 # of ignitions: 6,289 operating hours: 572.2 h
Range 2 # of ignitions: 894 operating hours: 572.2 h
Range 3 # of ignitions: 63 operating hours: 572.2 h
Range 4 # of ignitions: 1 operating hours: 279..9 h
Range 5 # of ignitions: 1 operating hours: 279.9 h
Range 6 # of ignitions: 0 operating hours: 0.0 h

Total hours on engine : 573.6 h
mileage: 20, 750
model: 2006

Service tech claims that car drives tight, RMS seal was replaced early in car's life at 4,000 miles. The area around the seal/engine is damp and was noted on the PPI sheet, with no signs of leakage.

I can't help but think the owner may have had a little "oops event" downshift and then decided to sell the car, given the range 1-3s...

I'd like some input from those who are more experienced than me. Is this a DME for concern? Thanks -

utkinpol

ok report, just confirm with service manager that those range 4 and range 5 counts of '1' are irrelevant.

it is interesting who 'tested' this car as it got its range 3 counts at 572.2h and total number of hours is 573.6h. dealer`s staff?

No HTwo O

Pass. The car has recent range #3 over-revs while in the hands of the dealership, not to mention range 4 and 5 over-revs. Range 1 and 2 are normal to have, but +6,000 in range #1 is very high.

Should have asked for the "free" DME report before spending money on the PPI.

Edgy01

It never ceases to amaze me that DEALERSHIP personnel seem oblivious to the tell-tale nature of DME reports, with the way they drive these cars when in their possession. Perhaps someone in the service department should be having a conversation with their sales staff about how much more difficult it makes their sales job when they, themselves, are abusing the cars either during demos or just while in their own hands.

BED997

The DME scan was done maybe an hour ago. I'm confused...

The service tech called me and told me that the car had very early overrev events (years ago), but the scan indicates this happened only 1.4 hours ago if I read this correctly.

I don't think a tech went on a joyride to check the car out for more than 30 mins ( they did tell me the car was driven for a check) - probably not one that lasted 1.4 hours... or am I completely misreading this report. If the total is 573.6 hours on the engine hours, and the events happen at 572.2 hours, could the tech have caused this?

Also, why would the owner go out and drive the car hard 1.4 hours ago if he was planning to sell it, unless he really missed a downshift last week and then got nervous about it. That to me sounds a lot more plausable.

Any thoughts?

BED997

just to add, this is a private owner's car, car does not belong to the dealer. THey were just running through the car for me.

utkinpol

if car has CPO it is all fine, as dealer calls 'overrevs' issues in upper ranges.
if car does not have CPO - well, decide for yourself. i do not like any data in 4-5 ranges, even if it is obvious bogus. ranges 1-3 are not such a big issue.

No HTwo O

Show the report to the car's current owner, and ask him what happened 1.4 hours ago. Then shut up (I mean this nicely) and wait for his response. This will tell you a lot. Buy the owner, not just the car.

Alan C.

Ranges 4 and 5 only show '1'. That's not even a full revolution.

ajayabb

Too many clean cars out there for the picking. You might be left explaining away these same over revs with PCA if you take ownership of this car and something goes wrong

jhbrennan

I never understood how you can have 1 overrev either. Also, the overrevs in ranges 1, 2 and 3 are not necessarily due to a mishift - could have been a very agressive run up through the gears. Unfortunately too the DME only shows the hour reading of the last event so you could have 10 overrevs at hour 572.2 and 6279 before - you just don't know. All in all this report wouldn't bother me...but you're the one buying.

BED997

Didn't work out on the car for this and other reasons. Thanks for the help guys! The search continues...

simsgw

No, it could not. Not unless those ranges have been described incorrectly in the past. Our engines don't have some whirly-gig style governor that can fall behind a quick-reving engine. The engine computer enables the spark for each cylinder (as well as the fuel injection pulse in DFI engines). Once it decides the car is reving fast enough and about to rev too fast, it simply declines to fire the plug. Engines don't accelerate without power pulses.

A downshift causes the kinetic energy of the car to be transferred to engine rotation and that's the only way you get any revs higher than the engine is programmed to permit.
I don't have personal access to the tech specification on this, but that is not the explanation I was given by Porsche. I was told the value under ignitions is the maximum for a single event, not an accumulation of ignitions over the life of the car. I find their explanation plausible. With a limited amount of memory, that's the logical way to program it. A hundred very short events are not nearly so punishing to the engine as one extended event. If their explanation to me was correct, then this report is telling us that the engine spent 19.6 seconds over the red line in one event at 572.2 hours. The mere 0.2 seconds in range 3, 2.4 seconds in range 2, and 17 seconds in range 1 are quite plausible for a blown downshift by a person too startled to react correctly.

You could do that by grabbing for third and hitting first at 45 mph, or conceivably by reaching for fourth and hitting second at around 80 mph. The latter sounds unlikely even for a track day since you're barely into third gear range at that speed and only a novice would shift into fourth at so slow a speed. The data do support a missed shift into third though. It reads to me (and would to a Porsche field rep I'd say) like a first gear engagement at the quite believable speed of 45 mph. At first, the car slowed rapidly, taking only 2.6 seconds to get down close to forty, but the driver did not disengage the clutch and let the car scream for another 17 seconds until it slowed enough to get the engine under redline.

Once again, I don't have the tech spec on that computer myself, so I can't confirm that interpretation of our DME print-outs, but that is the explanation provided to me and it is likely to be the one a Porsche employee would apply in evaluating DME scans.

Gary

USMC_DS1

Anyone know the details behind what a "1" means in this DME in those upper ranges? I had these on my DME in ranges 3, 4, and 5. The two Porsche tech's I've spoken to about these said these were erroneous and nothing to worry about. So just curious if there is a good explanation/theory out there.

jhbrennan

I find it hard to believe that the rev limiter can stop the rpm's at exactly the cutoff rpm especially when the engine is moving up through its rpm band aggressively. Here's what Scott Slauson, PCA Technical Expert, has said:

"Ranges 1-3 are just 200 RPM's apart in a spread for each range just for mainly info on how you are bumping the rev limiter. Ranges 1-3 are common for just winding up to the rev limiter at 7200 , inertia will generate up to range 3 at this time. This will depend on your driving."

Also, I'm not sure I understand what you're saying about the overrev ignition counter - if it is not cumulative wouldn't it always report the same number, what your tech called "the maximum for a single event"? I know that's not the case since I regularly check my DME with a Durametric and over time I have seen increments in range 1 overrevs.

I always find DME readouts an interesting topic since there does seem to be a lot of confusion and mis-information. I'm not a Porsche tecn nor an engineer so I could be completely wrong here but this is what I've been told and have read over the last 7 years.