2004 Porsche Cayenne 4.5L timing

Shane Technician Massachusetts Posted   Latest   Edited  
Resolved
Drivetrain
2004 Porsche Cayenne S 4.5L (B) 6-spd — WP1AB29P94LA65071
P0300 — Random/Multiple Cylinder Misfire Detected
P0301 — Cylinder 1 Misfire Detected
P0308 — Cylinder 8 Misfire Detected
P0491 — AIR System Insufficient Flow Bank 1
P0304 — Cylinder 4 Misfire Detected
P0305 — Cylinder 5 Misfire Detected
P0021-08
Check Engine Light On

Hello everyone, hope you are enjoying the holidays and staying healthy. To get right into it i have a 2004 cayenne 150000 miles with multiple misfire codes ( i have not felt it misfire the whole time i have been working on it ) a secondary air code that im not worried about at this time and a B2 timing code(p0021), which is the code in question. Also just so its known this vehicles exhaust is cut off about 10" after the manifolds, not sure why but its here for use to look at that too​. ​Not sure if cats were cut out by someone of if it was intentional at some point. I only have autel,snap on,pico, aldata and identifix at my disposal. 

I test drove the vehicle and and it seems to run great. I didnt save any screen shots but i think cam diviation was either + or - 3 on B1 and 7 on B2. actual cam timing was 0. when driving i could see actual moving and matching eachother. misfire data was all zeros all the time and i never felt a misfire. Roughness data for all cyl on B2 seemed to be in the 300's while all on B1 was realitivly good. Oil looks ok and full, not much other info to go on from aldata or identifix that i could find​. At this point i want to check timing so i search all waveform libraries i have access to. I found 1 in Pico library and for some reason im questioning its known good status pic and file #1, i would like your opinion on that. Then i scope this vehicle with solinods plugged in pic and file#2, then unplugged pic and file #3. It looks to me like plugged in is in time and what a known good should look like. Unplugged timing looks off, i believe i read some where the pcm will try to keep the cams in time if it can.

I then go in cyl 1 on B1 pic and file #4 , also cyl 5 B2 pic and file #5. I also scoped cyl 7 pic and file #6 becuse of what i saw in cyl 5. Im not good at finding IVO yet but i can see the EXT valve event is not the same side to side. A quick note about this vehicle is it has 4 cams but only the INT cams are phased and have cam sensors, EXT is unmonitored. The in cyl was done with solinods plugged in i didnt think to unplug them.I whould have done a relitive complression test but battery is difficult to get to​.​ Im thinking obut what other test i could do with what i have. Im wondering if the solenoid or phaser intermitantly failed but in the end it seems like the timing is out and you would go in and do everything anyway. What do you Intelligent minds think? 

0
Darren Owner/Technician
Colorado
Darren
 

From what I can see, the cam gear has 36 teeth. 10 degrees per tooth x .5 (cam:crank)= 5 degrees plus a little slack in the rest of the system…. 6-7 degrees, here ya go. I think at this point, regardless of what you diagnose with a scope, you’re confirming one inevitable fact- the engine is likely coming out for a timing chain/component repair. I think my next step would be to remove the…

+3
Ð Awarded
Helpful
Louie Technician
New York
Louie
 

Hi Shane whenever you have cam deviation exceeding 6 degrees in a VW Porsche engine it will throw a check engine light you most likely have a stretched chain between the cams in bank 2 and or the plastic chain pads that chain Rides on.

+3
Ð Awarded
Helpful
Sadel Owner/Technician
Ohio
Sadel
 

Shane, From looking at the pics you provided, particularly the 3 incyl captures…. you can clearly see the exhaust ramp be different bank to bank. Don't worry so much on trying to pick out the exact pinpoint of valve opening when the ramp gives you a good enough clear story on this one. The ramp on bank 2 is completed (in rising) by the 180 mark compared to bank 1 where it crosses the 180 mark…

+2
Ð Awarded
Helpful
Shane Technician
Massachusetts
Shane Resolution
 

Thank you for the help, it looks like from the comments that you guys have confirmed what I suspected, that the timing of out. I will be heading back to the shop today to do as Sadel suggested and get a cranking in cyl as well as an INT and EXT capture and I'm gonna try to get an RC also. More so to learn my scope and how to interpret waveforms as it seems this one is confirmed already. I do…

+1
Resolution Ð Awarded
Sadel Owner/Technician
Ohio
Sadel
 

As far as your question, the pico known good and yours with the solenoids plugged in match due to the fact that those signals are from the cam sensors on the intake cams bank to bank. Your engine is “off” on one exhaust cam only that has no sensor to create a signal, so since only the intake cams are captured and monitored it appears as if the engine is in time as far as cam and crank…

+3
Ð Awarded
Helpful
Agree
Shane Technician
Massachusetts
Shane Update
   

So i scoped cyl 3 while cranking and with intake pressure and RC, sync didnt show due to not clearing codes before i cranked. I also scoped cyl 6 cranking with intake pressure and in crankcase. I had the intention of getting exhuast but then remembered that exhaust is cut at manifolds, i figured i still could capture exhaust but would need each side individually and it would add confusion so…

0
Update Ð Awarded