Hello all,
I just purchased a 2008 997tt with 12785 miles on it and drove it 700 miles from Columbus OH to KC MO with no issues.
This morning I got in the car and when I started it, it sounded like I had my foot on the gas pedal... It shot up to 3500-4000 RPM's briefly and then settled into the normal high idle before the kick down to warm idle.

Any cause for concern here? I only have a few months left on the CPO and want to be sure I address everything that can be covered.

Car is stock with nothing done to it.
Has 13500ish miles on it.
Is beautiful and mine!

thanks in advance for any insight you might have. I wouldn't be concerned, except my 996tt never has never done anything like that.

Dan

 

Several here have reported this happening. Mine used to do it about once every 10 starts as well, but has not done it in probably a year.

There was a doc from Porsche that talked about adjusting the pulse sender on the flywheel (attached)

 

Common issue - BTDT - there is a long thread somewhere. There's an involved tech bulletin procedure to fix it which my dealer did under CPO warranty but the "fix" lasted only a few weeks.

 

Very common as stated. Just ignore it. It sort of comes and goes.

 

There are also reports that the startup spike triggers over revs in the higher ranges...

 

I do think I remember reading something about that... I just didn't think about it before posting this thread.

Thank you all. I'll schedule an apt at the dealer to have them check it out and I'll run a DME report to see if it registered any over rev's.

thanks all,
Dan

 

I check and record my over revs by taking a screen shot after every ride and the spike did cause over revs for me.

 

Wow...didn't know the ~3500 rpm spike could cause over-revs, especially into the higher ranges?!

My car has maxed out range 1 (65535) and a reasonable amount of 2 and 3s. It has six range 5 and one range 6. I get the spike maybe every 7 or 8 starts or so. If I ever have the tranny out will address it per the TSB, but for now, I just drive and enjoy.

 

Johnny, what ranges did it cause over-revs?

 

wtf, seriously?

why?

 

At what range? Weird!

 

What? That's odd... mine occasionally spikes up on start, but never over maybe 3k. I will put the pedal to the floor for a second while the car is in accessory mode prior to starting. I think it has helped minimize the frequency of the start up spike but I have no data to prove it.

 

clean the TB and recalibrate it(basic settings)

 

It needs to be cleaned and adjusted to 1.2 mm distance between the core and flywheel marks. Unfortunately, the engine must be lowered. It's a magnetic pick up. The sensor ring(flywheel) is divided into 60 segments. Each segment is divided into two 3-deg segments(high and low). The ECU can determine crankshaft movement in less than a degree. Now remember the system divides the crankshaft into three 120 deg segments. It looks for acceleration in each segment. These segments are equal to the distance of two ignitions. shown in the picture is my flywheel if you look closely, you can see the segments. The distance is critical because the iron core(coil) is trying to pick up these pulses induced by the rotation of the flywheel. I believe that this adjustment, if not set correctly will both cause incorrect data to be sent to the ecu and a definite 3k overshoot which has been addressed by Porsche. Now could this be the culprit as to the over rev register? (I) think it is. Picture shown is a pulse sensor properly adjusted. Note the two bolts shown, both where kind of lose on my car. I would experience the overshoot quite a lot. Also, I did notice a over rev trigger captured when one of these events occurred by pure accident. By the way mine was found at .8mm! Also, none of this is made up crap like some of the stuff read here. Info can be found on Porsche advanced engine management systems page 11 part of the misfire monitor system. My engine does not do this anymore! I kind of replaced everything from the flywheel( expensive) PP,clutch, fork, bearings I mean everything all OEM stuff. Including the slave! My car had 54k miles and the clutch and flywheel still looked great! Measurements with my instrument showed very minimal wear on the clutch surface. in fact, my OEM flywheel(Luk) and clutch/PP(SACHS) are still in my garage as decorative reminder of all my hard work. Saved tons of cash doing this and a massive boost in my mechanical skills. I also fixed the coolant leak from the pesky plastic elbows which is why I removed my engine in the first place. Sharkwerks provided those for me. **** looks awesome now. Many thanks go out to some on this forum and a big one to Sonnen Porsche for all my OEM parts. Best prices on parts without a doubt!

 

My car is still under CPO. How would you approach your dealer to let them know you wanted this done under warranty?
My question is... Since it doesn't do it often, (Only once in the 1000 miles I've owned the car), what phrase do you think would get them to make the adjustment based on my description of the issue?

Dan