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Old 06-26-2012, 03:08 PM   #1
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Causes of Camshaft deviation other than IMS

What could cause Camshaft deviation to fluctuate on one side other than IMS issues?

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Old 06-26-2012, 05:04 PM   #2
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IMS drive sprockets that have slipped on the drive tube are the most common.
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Old 06-27-2012, 02:30 AM   #3
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Fluctuating Cam deviation

Is this something I shoudl be concerned about. IMS was replaced with LN bearings but I am getting a + or - .3 fluctuation on one side.
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Old 06-27-2012, 03:35 AM   #4
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Spec is +/- 6 degrees
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Old 06-27-2012, 09:53 AM   #5
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Having the same issue. I was throwing a solid CEL and 1531 code, meaning variance on Bank #1. I assumed it might be the IMS, since I got the car over a year ago with no maintenance documents. Had no idea if it was ever done. Just finished putting the new IMS bearing in and the old one looked fine. No wear apparent, but it was filled with engine oil, so just a matter of time. I feel better knowing what's in there now.
When I locked it at top dead and put the cam lock on, everything lined up perfect. Where might the deviation be? Wear pads?
Getting ready to button it back up, check cam timing again, and give it a go.
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Old 06-27-2012, 11:56 AM   #6
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Unusual cam values could be a number of things; wear pads, chain slop, weak tensioners, VarioCam components going south, bad position sensors, etc.

That said, P1531 is usually associated with a failing VarioCam actuator on bank 1 however.
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Old 06-27-2012, 12:22 PM   #7
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here is the best picture i've ever seen regarding chains, ims, tensioners, paddles, etc.; also does a good job of explaining the various ims flanges out there:

http://www.pelicanparts.com/techarticles/Boxster_Tech/16-ENGINE-Camshaft_Swap_and_Chain_Tensioner/Gp1800.pdf
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Old 06-27-2012, 01:04 PM   #8
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Quote:
Originally Posted by JFP in PA View Post
That said, P1531 is usually associated with a failing VarioCam actuator on bank 1 however.
That makes sense, bank 1 could be holding back while bank 2 is ramping up. Would definitely give a wide variance number. I'll head that direction.
No way to test the actuator without the PST2 scanner is there? I have a standard OBDii scanner. That will only tell me where the problem is, not what's causing it.
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Old 06-27-2012, 01:16 PM   #9
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durametric will do it.
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Old 06-27-2012, 01:45 PM   #10
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P1531 indicates that the actuator is triggering, but that the cam is not assuming an active position on Bank 1. Usually, this requires replacing the actuator, assuming no wiring issues. P1539 is the equivalent code for bank 2.
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Old 06-27-2012, 02:37 PM   #11
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So that tells me (barring wiring problems) that the solenoid is firing, the actuator is hanging up/ not engaging the whole way?
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Old 06-27-2012, 03:04 PM   #12
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Most likely.
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Old 06-27-2012, 03:31 PM   #13
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Then the faulty actuator won't cause a variance that could hurt the engine, just performance. I shouldn't have a problem clearing the code and giving it a run or two to check it out. I think it takes about three cycles to throw a new code, right?
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Old 06-28-2012, 03:08 AM   #14
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Actually, I would not be driving the car in this condition. Besides throwing codes, one side of the engine is running under cam position conditions that are different than the other side. While it may not cause bigger problems for some time, it ain't really a good thing...
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Old 06-28-2012, 03:58 AM   #15
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I agree for sure. I'll be fixing it right away (wife wants her daily driver back). I just want to run it quick to check out the IMS repairs I did. Actuators aren't rebuildable other than the wear blocks, are they?
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Old 06-28-2012, 09:44 AM   #16
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The VarioCam actuators are not rebuild-able, and are separate from the wear pads on a five chain motor, but it would be a good idea to replace the wear pads while you have the system apart; they are a “consumable” item not unlike brake pads.
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Old 06-28-2012, 09:58 AM   #17
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not that i would wait for it but, would the deviation cause a CEL to illuminate and if so, at what point could that be expected to happen?
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Old 06-28-2012, 10:34 AM   #18
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@Tony- That's what started my quest. I had a solid CEL and when I read it with the scanner I got a P1531, meaning a cam variance on bank #1 that was outside of tolerance. I'll be heading into the variocam next...
BTW, I'm at 120k now, but the car was purchased without documentation, so I have no idea what was done in the past.

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Old 06-28-2012, 11:02 AM   #19
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gary_d: any idea what your current deviation number(s) are?
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Old 06-28-2012, 01:09 PM   #20
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Unfortunately, I don't. I only have an OBDII scanner to tell me there's a fault Trying to line up with a PST2 or Durametric right now to delve further.
JFP says the acceptable is +/- 6 degrees though, so if you have access to the correct scanner you'll know if you're in tolerence.


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