Camshaft deviation out of spec - next steps?

[DMage]

Been diagnosing an issue with a P1115 and P1130 CEL, and Durametric has been helpful with all of that. However, I feel that Durametric could also be a ‘too much information’ type tool - as now I am worried about everything! Seem to fix one thing, and then find something else right behind it!

2000 Boxster S, 83k miles

When I first ran the Durametric several days ago, I checked cam deviation. I was -6.77 in pos 1, and -5.73 in pos 2. I know specs are +/- 6. Test was done at idle on a cold engine warming up.

Ran the other day after a spirited run, and I was -7.19 in pos 1, -5.91 in pos 2. Again taken at idle, but fully warm this time.

Checked it again this morning, pos 2 was still at -5.91, yet pos 1 started at -7.14, then went up to -8.14, then down to -7.69, then to -7.64. This is over the course of 15 minutes while the car warmed up. Pos 2 did not change.

Is this the ‘bouncing around’ I’ve heard about that signifies an IMS impending failure? It wasn’t rapid, but a slow increase and decrease. I had just changed the oil 300 miles ago and there was no debris in the stock filter. Pulled the filter again yesterday and nothing in it. Have not dropped the oil tray yet. IMS is on the list at this point anyway to do soon.

From other things I’ve read, it could be the variocam pads, or tensioners, or a sensor. Guess I am just trying to identify what my immediate next step should be?

I was thinking start with the IMS, and check timing in the process. If timing is off, I was going to follow these instructions to reset. I do have the locking tools available also (already have the IMS install toolkit): http://986forum.com/forums/performance-technical-chat/26418-diy-setting-cam-timing-m96.html

Need to do some additional reading in the manuals, but, also looking for advice / input on next steps or thoughts on the cam deviation #’s. Thanks!

[flaps10]

Chain ramps are also a source of deviation. Not just the vario cam pads but the long ones, and the two you can't reach without a tear down. They get quite beat up. Your asymmetric condition would have me start with the ones you can reach.

You'll need more special tools to expose the ramps

[DMage]

Digging around for more info, I wonder if its just a better bet to handle the IMS / RMS / Clutch / Variocam pads all as one job, since I'll have it up in the air, the cams locked, and some stuff out of the way already.

[Giller]

Are you seeing any little bits of plastic in the filter? If you pull the sump, from my understanding and experience - there will be some plastic bits. It's apparently normal to find some as the ramps are plastic and do wear down - but if you find a large amount, that is a good sign your ramps are in need of replacement.

I was finding larger and larger amounts when I started getting deviations on 1 of +8. My indie suggested it's probably the ramps more than the IMS in my case.

[DMage]

Have only had the car for the past 600 miles of wear but only a tiny minute bit of black plastic in the filter when I changed the oil. So will pad wear show positive deviation numbers only as mine are negative?

Sump drop is up next from the sounds of it.

[thom4782]

My understanding is this

1. Camshaft deviation readings are valid only when the engine is fully warmed up. They change as the engine warms up and can mislead you
2. If one or both deviations are out of spec, you probably have worn variocam pads. If they wear too much, the engine can jump timing
3. The camshaft deviations should remain steady at idle. If not, it may be the IMS starting to wobble
4. When the variocam solenoid is the problem, you'll see this in the camshaft angles when the engine RPMs are in the 3000 range. The numbers will be significantly different.

Hope this helps

BTW: Just replaced my variocam pads and they were worn. My deviations were negative and got more negative over the past two years

[DMage]

Thanks on confirming the negative #. Going to take it for a quick drive to get it up to temp and then retest to see if I match my fully warm numbers from the other day. Either way I am out of spec so figure it's time to do the pads.