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A friend and I have been struggling with a strange problem with his 2006 997 4S with tiptronic transmission. When you start his car you need to turn the key and let it crank on the starter motor for around 10 seconds before it will start, and when it does it seems to be a bit lumpy for the first second or two. However, if you shut it down while it is running and restart it right away it fires straight up within a second. We have pulled off a coil pack and put a new plug into it (earthed out with a jump lead) and observed that while it is cranking there is no spark, apart from maybe one every 3 seconds, and then rapid sparking at the plug as soon as it fires up. We have also hooked up fuel pressure monitoring kit to the car, and the fuel pressure seems to be right, as I thought it may be the fuel pump check valve or pressure regulator bleeding off pressure, but then we discovered what was happening with the spark not being there until 10 or so seconds of continuous cranking. We have hooked the car up to the PIWIS and PIWIS-2 that the local Porsche approved bodyshop loaned to us, and there are no fault codes anywhere. We also had hoped to watch the live data while cranking, but it seems that communication disconnects during starter motor cranking, which we are told is normal. The strange thing is that the car idles fine, runs fine, no hesitation, we have followed the Porsche test plan for checking the mass airflow sensor, we have used a smoke machine on the intake to look for vacuum leaks, we have even checked the various temperature sensors on the PIWIS and all seem to be reporting good temperatures. While we had the PIWIS-2 we even reprogrammed the DME with the latest software, which it said was already loaded but we did it anyway in case something was corrupted. We have even disconnected the battery over night and tried the various re-training adapting methods on the internet. Fuel trims are all hovering around 900 and 1.1 We have even changed the crank sensor for a new one and no difference. If it were not for the loss of spark, I would be tempted to say it was the fuel pressure bleeding off, because it is a little like it is trying to get fuel back up to the injectors when cranking, which would also explain the way it only has this problem 5 mins after shutting the engine down, but not less than 5 mins. Does the 997 DME monitor oil pressure before it supplies a spark? My reason for asking is that this would also be something which would match up with the symptoms, once the oil pressure has bled off completely, it would take a few cranks to regain it, especially if the oil circuit had a fault... But when running the oil pressure is good, however it does seem to be that the oil pressure is at the bottom on the instruments when cranking and either it shoots up and then the engine runs, or maybe it just shoots up due to the engine running at a faster speed than starter motor cranking. We even worried it may be cranking a little slower than the DME was happy with, so even replaced the dreaded alternator/starter motor/charging harness on the engine.. Which now has it cranking a fraction faster, but still the same problem. Having compared the cranking speed to my Boxster and 996, it seems to be turning over at the same kind of speed. Any ideas anyone??
dinicor posted a topic in 996 Series (Carrera, Carrera 4, Carrera 4S, Targa)Doing the plugs and coils on my 2001. I know this has been asked before, but the info I have found is inconsistent. I've popped just the plugs in so far and put some anti-seize. Should I pull them and take it off. I've read mixed reviews on this. I also ordered new ignition coils. Do the coil tubes come pre-lubed with grease? If not, should I add some? Thanks