Cam Deviation and Variocam Solenoid Testing Confusion

[BoostDR]

Hi from Down Under (Aussie). In an attempt to ensure I can efficiently chase Kangaroos down the street and also avoid "drop bears" I conducted a health check on my 2000 2.7ltr 986. The results weren't so great....

 

Diag Tool: Autel AP200 

 

Readings:

                 Camshaft Deviation Bank 1:             -9.45 (best I saw was -8.3)

                 Camshaft Deviation Bank 2:             No Reading available on my tool

                 Camshaft Actual Position Bank 1:   Happily goes from 0 - 25 - 0 as the Variocam activates and deactivates  

                 Camshaft Actual Position Bank 2:   Starts around 0. Doesn't change on activation. Slowly goes up to 20 at max rpm(at Max rpm it should be 0ish)...not Solenoid activation affected 

                 Fault Codes:                                         No Fault Codes

 

Tests:

                 Bank 1 Solenoid Resistance:            13.7 Ohm

                 Bank 2 Solenoid Resistance:            15.2 Ohm

                 Bank 1 & 2 Sol Current Draw:            0.770A 

                 Bank 1&2 Solenoid 12v at idle:         Both Change engine note substantially 

                 DME output to Bank 1 & 2:               Both 13.06v on activation 

                 12v direct to Bank 2:                          Nil effect to Actual Cam timing however clicking can be heard and engine note does change at idle. At rpm I can feel a difference

                  Disconnected Bank 1 & 2:               Couldn't notice too much difference to power or delivery 

 

I've changed one of the variocam pads on the right hand side of the engine(looking from the back of the car) My diag tool tells me that is bank 1....which has huge deviation for which it shouldn't. I do have a reasonable chain rattle at start up... always thought this was normal. 

 

So......Do I actually have an issue? is my Autel scan tool leading me up the garden path ?? All physical tests point to all fine. Scan tool tells me other wise.

 

A little stumped, Help Please 

 

 

 

 

 

                

Edited August 31, 2019 by BoostDR

[Ahsai]

I haven't tried the Autel scan tool so not sure how accurate it is. It would be nice if you could recheck everything with a Durametric.

 

Assuming the Autel readings are correct, your bank 1 cam deviation is not in spec and should be corrected. You may want to replace the bank 1 chain tensioner and retime bank 1.

 

The bank 2 cam behavior sounds suspicious. Could be the variocam actuator problem (sticky). Would be nice to check with Durametric to confirm before digging in further.

Edited August 31, 2019 by Ahsai
Corrected typos

[BoostDR]

Thanks Ahsai. I’m going to pull the green plugs and check the physical timing today. 

 

Im also not trusting of the Autel. Certainly when I activate bank 2 at idle the engine stumbles however the data shows

no movement in cam angle. This doesn’t make any sense to me as when I do the same on bank 1 it moves 25 degrees per the data...and makes the same change in engine note 

 

 

Matt

[BoostDR]

Looks like the intake cams are a bit off. More like 3:15 rather than 2:45 ?

[BoostDR]

Hmmm. 

 

Doesnt look right...

 

Ahsai said bank 2 vario cam solenoid sticky..... looks like you were correct 

[Ahsai]

The spring came out like that? Also, are there any o-ring on the piston? Hard to tell from the pic.

[Ahsai]

This thread will give more info.

 

"Lazy" VarioCam, P1341 - Rennlist - Porsche Discussion Forums

RENNLIST.COM

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996 Forum - "Lazy" VarioCam, P1341 - UPDATE: IF YOU ARE SEEING SMALL BITS OF GREEN O-RING-ISH RUBBER IN...

 

[BoostDR]

Yes came out like that. I’ve re-shaped it. 

 

No O’rings at all. It feels a bit loose in its home. Are there meant to be O’rings ? 

 

About to pull the cams out. 

 

Matt

Edited September 14, 2019 by BoostDR

[BoostDR]

[Ahsai]

Actually I'm not sure. You may want to PM Schnell Gelb and porschetech3.

[BoostDR]

Hmmm

[BoostDR]

I’ve put it all back together with the new pads. Car feels slightly different and the deviation is slightly better but still between -7, -8. 

 

Timing does advance but very slowly. Looks like the variocam assembly is faulty.  I tested the variocam on the bench with compressed are and 12v activating the solenoid. It worked as expected but obviously in the car. Doesn’t have enough pressure. I suspect my inner variocam green seals are done. If I recall I did see some green rubber in the filter on a previous oil change. 

 

Anyone know now how the cheapest is for a variocam assembly ? 

 

Matt