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-   -   Untenable cam timing results (http://986forum.com/forums/showthread.php?t=85511)

UAL96AMT 03-18-2024 09:47 AM

Untenable cam timing results
 
I have a question regarding a rather strange reading and symptoms i'm experiencing on my '99' Boxster tiptronic 164K miles. I purchased this car not running. It had a bad transmission but included a replacement with the car. The price was low enough that I figured, "lets take a chance". The seller claimed the engine was good, just a bad tranny. Okay, like I said the price was right. After towing the car home I started straight away and removed the engine/transmission assembly so that I could split the two and replace the transmission. This is my first Boxster... I also learned about various small items internal to the engine that should be replaced while the engine was out. It included an LN Engineering IMS bearing, Vario Cam Pads, cam chain guide rails, and a bunch of other stuff. All went well and the car sprung to life without hesitation and runs smoothly and evenly. Fast FWD 6 months... SAI fault CEL went on then off. Then SAI CEL illuminated and stayed on. I went through the steps of checking the SAI system out. Fan runs and operates, puts out good air. To make a long story a little shorter I ended up replacing every single component in the SAI system including the fan. No Help! I then went to check intake manifold vacuum to see if there's an issue there. 13in Hg steady. I felt this was a little low and since the SAI system is powered by vacuum and actuated by electricity I decided to check cam timing with my Launch CRP129 scanner. I found that bank 2 cam was off by 756.32 degrees when at operating temp, and upon first start up it's 25+ degrees then starts climbing. Since these readings are impossible I threw a Hall sensor (cam position sensor) at bank 2. The results were the same. At this time I have removed the engine (again) to check timing. it's still dead on, no issues with timing, and yes, it runs fine, only issue is rather low intake manifold vacuum and SAI fault. I have rung out all associated wiring on the engine harness, and associated hall sensor wiring. Ring out good. At this time I'm at a loss. I can find no obvious faults and am considering throwing a vario cam actuator at bank 2. Has anyone come up against this set of problems before? Thanks for the interest and assist.

JFP in PA 03-18-2024 01:29 PM

I would suspect your scanner; there is no way the timing can be that far off and still have the car running. Get the thing scanned with a real Porsche tool before you do anything else..................

UAL96AMT 03-18-2024 01:46 PM

Thank you for your reply. Yes, your sentiments are mirrored by a number of people. Presently i'm going to skip the new Vario Cam actuator and reassemble the bank 2 cam cover and associated hardware and then reinstall the engine. But before i do that I will smoke test hoses/plumbing just in case there's one or more leaks 'generally' on the engine. i'm afraid it's time to invest in a good scan-tool

Gilles 03-19-2024 06:44 PM

from time to time a used Durametic Tool shows up for sale here and also on Rennlist for a very reasonable price.

There are other tools as well but I am not familiar with them to make a suggestion..:rolleyes:

UAL96AMT 03-19-2024 07:47 PM

Durametric is in my sights: at this time the engine is reassembled and ready to go back in the car. I also performed a smoke check of the intake system and found a cracked vacuum line to the evap solenoid and the new AOS lower bellows tube also had a leak. These two were addressed and no other leaks were noted. Once the engine is back up and running the hope is better vacuum numbers and then I will address interrogating the ECU with a more suitable scan tool. The AOS is brand new and was replaced this maintenance cycle so it's a good thing that I took the time to check everything before the engine went back in...


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