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Owned 911 for 2 days before engine problems

AeroAnt

Well-known member
Joined
20 Nov 2012
Messages
141
Where to start. Sorry for the long post!

Hoping someone can give some advice on normal Porsche procedure and also the likely cause of my problem

Picked up our 997.1 on Monday evening and everything seemed well until Wednesday evening.

After filling up with approx. 20litre of fuel, already had half a tank, about 15 miles i had problems with the revs, it would not rev about approx. 4200 rpm... this was followed by the check engine light. I thought maybe it was just a phantom limp home mode due to the heavy rain(wishful thinking). I pulled into to a petrol station switched the car off and restarted it. No check engine light and everything is running smoothly again, then attempt to accelerate and the same thing happens, very noticeable misfire at approx. 4200rpm massive hesitation i let off and the check engine light comes on.

I call the recovery people who advice unless the check engine light is flashing it is OK to drive back home and they will recover the car in the morning. So that is exactly what i do. RAC/Porsche turn up early morning do some checks and tell me i have codes p0300,p0301,p0302,p0303 and that they would recovery it to my local Porsche. Great i think.

Next day i get a call advising the warranty might be void due to an over rev in range 4. Which apparently is a missed shift. I know categorically i have not missed a shift, i let them know that i have hit the limiter on the way up a few times in 2nd gear but not not missed a shift. According to OPC the only way a Range 4 would come up is if i have downshifted into the wrong gear. I 100% know this hasn't happened. I have driven approx. 260 miles since owning the car of which 200 miles have been relatively gentle motorway miles.

So i am really confused at this point, racking my brain trying to remember if this may have happened without me realising. Check through the forums it would appear a range 4-6 would be a noticeable miss shift. I call them back, but they are saying they have spoken to the head tech and he said the data is 100% accurate and that in order to find out if my warranty is valid i would need to pay for compression/leak down test. They cant give me an exactly time it happened only that it happened after the ran the checks before handover??. Fortunately after speaking to the OPC i bought it from, they agreed to cover the cost for this.

They haven't even given me an indication on what the issues are as they are not prepared to do anything until Porsche check the leak-down and over rev. The OPC i bought it from think that the timing may have slipped based on the information i gave over the phone.

Because all of this was done on Friday, they could not get an answer from Porsche UK. I assume it will be Monday/Tuesday.


My questions are;

How reliable is the over rev data and how do i know it wasn't done before i collected the car? I know that it went to be 'detailed' before i collected it.

With the fact the car runs perfectly fine under 4200rpm, could it simply be a sensor issue cam/air etc?

Has anyone had a similar issue?

How likely is it porsche will refuse a warranty on a car that has been run for 260 miles since purchased from OPC?

The car is OPC bought with 2 years warranty, 45k miles, 55 plate.
 
Doesn't the ECU record when the last over-rev occurred?

The dealer needs to be told that they need to prove that you caused the over-rev in order to legally invalidate the warranty. Even if the car wasn't under the Porsche warranty, you have legal grounds to reject the car under the Sale of Goods act. But don't listen to me - get proper legal advice. At the very least, talk to Trading Standards.
 
First off, hi!

Your issues sound coil pack related, especially if it happened in heavy rain. No biggie, very common issue, I wouldn't worry too much about it yet.

With regards to the over revs, it is possible for the data to be wrong. In essence, if you only had 1 rev in R4 then that would be impossible, as the engine would have to be in that zone for such an infinitely small amount of time it simply could not happen. Likewise if you had more revs in R4 than in R3, that's also impossible as it would have to go through R3 to get to R4. Basically you'd need to get the numbers for us to have a look at, they will give them to you.

The over revs also tell you when it happened, so if it was after you owned the car then you're stuffed, but if it happened before you took ownership then it's their stuff up and you won't have to pay a dime. You won't be able to renew your warranty either, but that's a couple of years away yet.
 
Thanks for the fast replies.


Apparently it records only the operating hours it occurred at? Which seems like it occurred between agreeing the sale and it breaking down. So there is possibility that it occurred while in there hands. Not that i'm suggesting it did until i get more details from them tomorrow. Im not even sure it has happened at all, certainly not in my hands.

I did think Coils/spark or cam sensor etc. What made me worry was that i assume that they would check the codes and have a fairly good idea of what is wrong. I probably wrongfully assumed that if it was simply coil pack or similar that they would be able to rectify this without doing a leak-down test and checking with Porsche UK. But after some discussion with the OPC, it would seem once they get an over-rev flag they 'have' to check with Porsche UK to ensure that they are willing to pay for warranty work no matter how small or big the cost?? I guess that as its not the OPC i bought it from, they are just covering themselves in terms of getting paid.

Its just a bit daunting hearing, in the first instance; 'engine leak down test at your cost' & 'possible non warrantied engine work'. All seems a little OTT if they know its likely to be a sensor or coil-pack.
 
Dan, I just don't follow your logic wrt number of overrevs in each range. What you are saying is like saying it is impossible for the engine to spend more time in the 3-4k range than in the 2-3k range because it has to pass through it. I agree it is unlikely, but not impossible.

I know on the 996 it tells you the engine run time at which the last one occurred, the garage can use this to show that it happened in the last few hours but not how many of the total events occurred at that point. I.E. 234 total ignition events, last at 567 hours, current run time 567.2 hours.

MC
 
Your codes are all random misfires on all cylinders of bank 1-3 and I suspect it'll be coil packs getting wet. It could be vario cam issues as I had similar problem with a misfire at 4500 revs and was told it could the vario cam sensors as this is when they start to work. Mine turned out to be a dry connection of the engine wiring loom though.

I seem to remember someone on here getting Warranty even with an over rev after the compression was checked by OPC. So as long as the compression test turns out OK you should be able to renew next time and maybe claim this time.
 
MisterCorn said:
Dan, I just don't follow your logic wrt number of overrevs in each range. What you are saying is like saying it is impossible for the engine to spend more time in the 3-4k range than in the 2-3k range because it has to pass through it. I agree it is unlikely, but not impossible.
Not quite. If the ECU says that you have had 100 in R4, but only 50 in R3 that would be absolutely impossible to achieve. R3 is between 7700 and 7900, R4 is 7900 to 8400. As such the engine must pass through R3 to get to R4, and therefore the engine must spend at least twice as long in the lower range: Once to get there, and once to get back.



Not directly related, but to give a more exact idea on the numbers and length of time spent in these ranges, ths is pinched from Planet9:

So if range 4 is 7900 - 8400rpm and then the engine fired 86 times in that range, that works out to:

86 / 3 (ignition cycles per revolution) = 28.7 engine revolutions

Assuming the average speed of the engine in that range was ~8000rpm, then:

8000rpm = 133.3 revolutions per second
Time spent in range 4 = 28.7 / 133.3 seconds = ~200ms
 
Ekona said:
MisterCorn said:
Dan, I just don't follow your logic wrt number of overrevs in each range. What you are saying is like saying it is impossible for the engine to spend more time in the 3-4k range than in the 2-3k range because it has to pass through it. I agree it is unlikely, but not impossible.
Not quite. If the ECU says that you have had 100 in R4, but only 50 in R3 that would be absolutely impossible to achieve. R3 is between 7700 and 7900, R4 is 7900 to 8400. As such the engine must pass through R3 to get to R4, and therefore the engine must spend at least twice as long in the lower range: Once to get there, and once to get back.
Unless I'm being thick (quite possible) I agree with MC on this one; yes you have to go through the 7700-7900rpm range once on the way up and once on the way down but you could theoretically spend however much time you like in the 7900-8400rpm range before you come back down through the 7700-7900rpm range.

The only thing that would be impossible is having just 1 ignition in the 7700-7900 range, you would have to have at least two (one revving up, one revving down again) but you could have 20 on the way up, 500 above 7900 then another 20 on the way down couldn't you?

Obviously the big caveat here is that the limiter should stop you revving to that level of rpm (sorry not sure where the limiter is on a 997) but assuming it doesn't, it's perfectly possible to have more rpm in the higher 7900-8400 rev range than in the 7700-7900 range I would have thought...

:dont know:
 
I can potentially see how that is possible; If the majority of the over rev was in the top band, and say you keep your foot in it for the duration until you realise that you are banging off the limiter then rapidly allowing the revs to drop could theoretically allow more registered over revs in the upper band than the lower, which it would pass through more quickly. THEORETICALLY. Really i have no idea how these are monitored or registered.


What i don't see as possible is registering a range 4 mechanical over rev without knowing you have done it. Fair enough if i had owned the car for a extended period OR had tracked it, maybe i wouldn't remember. But not 2 days to and from work followed by a trip to the petrol station. Which is why i wonder how accurate the over rev recording is. That is assuming it hadn't been driven before collection
 
My coil packs gave up in wet weather too, they get hot and crack I'm led to believe, then let moisture in, they ain't expensive, I prayed em with wd40 for a few weeks then replaced em.
 
AeroAnt said:
What i don't see as possible is registering a range 4 mechanical over rev without knowing you have done it. Fair enough if i had owned the car for a extended period OR had tracked it, maybe i wouldn't remember. But not 2 days to and from work followed by a trip to the petrol station. Which is why i wonder how accurate the over rev recording is. That is assuming it hadn't been driven before collection

You would know if you'd over revved it.

Who knows when OPC did their pre purchase check on the ECU, what work may of been done inbetween, had it been taken out on a test drive by someone else???
 
Ant Blain said:
Unless I'm being thick (quite possible) I agree with MC on this one; yes you have to go through the 7700-7900rpm range once on the way up and once on the way down but you could theoretically spend however much time you like in the 7900-8400rpm range before you come back down through the 7700-7900rpm range.

The only thing that would be impossible is having just 1 ignition in the 7700-7900 range, you would have to have at least two (one revving up, one revving down again) but you could have 20 on the way up, 500 above 7900 then another 20 on the way down couldn't you?

Obviously the big caveat here is that the limiter should stop you revving to that level of rpm (sorry not sure where the limiter is on a 997) but assuming it doesn't, it's perfectly possible to have more rpm in the higher 7900-8400 rev range than in the 7700-7900 range I would have thought...

:dont know:
Right, I see what you guys are getting at now. I agree, however you'd end up with an engine that was damaged straight away and you'd know about it instantly or you'd have spent so long there that, you wouldn't be able to forget as you'd spend the next year worrying about it.

I guess we really need to see the over rev numbers per range here to have a sensible guess at anything else.
 
Just to chip in. Lots of cleverer folk than me on here, but from my experience of coil pack failures when they go they go and it manifests itself at all rev ranges from lumpy idle upwards. So if your issue only kicks in above 4k I'd be very surprised if it was coil packs. Hope you get it sorted.
 

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