First many thanks to Doug, Kevin and Logray. Also to the wealth of knowledge everyone contributes to the Porsche forums.

Finally resolved a P0305 that would occur only at idle (low RPM). The symptom was flashing CEL once the car warmed up and was idling. After obligatory plugs and coil replacement I attempted swapping injectors. Scouring online it looked like a dreaded tappet/lifter issue.

I can now report the car is CEL free and yes I had a stuck tappet. Turns out it froze in the high (11mm) position, which I read had not be recorded online yet.

The fix was a replacement of all bank 2 lifters on exhaust and intake. This could of been achieved with replacement of just the one bad lifter on intake valve cylinder #5 but wanted to do a proper preventative fix. Also done was 997 ver. or RMS + IMS fix + Redline 75w-90 NS in trans.

Do not attempt such a repair without all the needed specialty Porsche tools. These were essential in the success and rough list is #9685, #9686, LN engineering IMS tools (includes TDC pin + cam lock), P256. Roughly $1k in tools and worth every penny vs. $4k quoted indy price or cost of a mistake (-$10k from engine death)

Also you must buy the proper replacement parts Ie new bolts for intake camshaft, new lifters, Locktite 5900, new cam plugs, solenoid gaskets, oil pump gasket, spark plug o-rings etc etc. These a peanut cost if you consider the time it would take to redo all the work! BTW must learn about TDC for bank 1 vs 2. They are 360* of crank rotation difference. Ie if you are planning to reach 60* before TDC of bank 2 you would move beyond a 360* rotation, to 660*. Bank 1 TDC appears to be lobes of inlet/exhaust facing inward. Bank 2 TDC is lobes facing away from each other.

I will add pics once I wipe the stupid grin off my face from driving the newly repaired car. In a nutshell: Move to TDC of proper bank+lock w/ pin, pop trunk, pull light wiring, remove tails, pull rear bumper, remove muffler shield 10mm+muffler (13mmx3+17mmx2), heat shield 10mmx2, 5mm hex for coils+solenoids, lock cams w/ tool, loosen both 18mm engine mounts, 8mmx4 scavenge pump cover, specialty tool+16mm remove intake cam bolt, 4x10mm exhaust cam, remove tensioner (I had the special fun of bank 2 that involves removing PS pulley, PS line & then 6mm hex alternator mount to reach the 4-5-6 tensioner which is a totally obscure 14mm hex), 10mmx30 cam housing, mount cam holding tool, remove+cover and label cam guide rails, remove+cover cams, swap lifters.

Special pattern is required for Locktite 5900 on cam cover and must only use 1.5mm bead. Now on reinstall it is roughly same process except, you lock cams and rotate assembly to 60* before TDC (660* total since otherwise wrong TDC) lock with pin and tighten the tensioner to 59 ft/lbs. Only then do you rotate to the full TDC to tighten the exhaust and intake camshaft (with special tool 37 ft/lbs then remove cam lock then do 110*)

Hope others don't have to do the same but feel free to PM me questions. It was a great experience and glad I was able to fix the issue. My only complication was the solenoid on bank 2 decided to die. Resulting in a P1325 that was solved by replacing the solenoid to restore the proper cam forward/backward adjustment.

 

PS: So if others are facing a P1325 I've read that the turbo 996 engine has an issue where the ring on the inlet camshaft can break down. This will result in lack of sufficient pressure to the Variocam Plus and throw a code. Might be worth confirming your rings are still present if facing such an issue. I did not encounter that issue on my NA 996.

 

HI B8-RDC,

Iam having P0305 on my porche panemera 4.8 v8. Its giving cilinder 5 all the time. I replaced the spark and the coil but still same issue. Do you know what else it can be?



Regards,
Faim

 

Faim you might want to check the Panemera forum. My issue was a rare stuck lifter. There are two positions that the lifter can generate depending on the command from the DME. My mechanical action was frozen on lifter #5 and needed to be swapped out. Stoked you read my post since it was a tricky fix.