PorscheG96

Is there a specific mileage when the tensioners or other components need to be inspected or replaced? What's the worst that can happen if/when they fail?

Macster

Change the oil/filter at reasonable intervals and use an approved oil.

Other than than, just drive the car.

Barring the rare premature failure you'll wear out the brake light switch, a door lock, a window raise/lower mechanism, and so on before the Variocam hardware acts up.

I wore out all of the above, and more, before my 02's passenger side VarioCam solenoid/actuator acted up and both had to be replaced. I forget now the mileage at which the passenger side hardware was replaced (it was done about a year ago) but I note the driver's side VarioCam solenoid/actuator are just fine and the car has as of last night at 6:49pm 251,933 miles.

I do not know what would have happened had I continued to drive the car for long after the initial symptoms appeared, but I did manage to drive the car 30+ miles home from the office and a few miles the next business day from home to the local dealer. I did baby the engine a bit, keeping rpms under 4K on the drive home.

If one continued to drive the car for say oh don't know but how about a WAG hundreds and hundreds of miles I could begin to worry about damage to the tensioner rails/guides (the material).

But upon teardown the guides/rails on that side of the engine anyhow (never opened up the other side) looked brand new.

The very worst case if the solenoid/actuator fail is that this failure causes excessive wear/tear of the IMS to exhaust camshaft chain drive tensioner/rails and guides.

But unless one continued to drive the car long after the initial problem occurred...

I suspect one would tire of the engine's behavior in this condition long before the engine started to come apart, if it even would come apart.

Sincerely,

Macster.

logray

For the "pre externally accessible" variocam actuator engines...

Just drive the car pretty much until it throws a code idles very very poor (and diagnosis is variocam). Or if you pull the cam covers off, at which point, cough up the $700 for the actuator/solenoid assembly (discounted/per side/not incl. labor).

As Macster pointed out drive the car hard and change the oil often. When they get dirty or used sparingly, my thought is they won't last as long.

bmuhonen

Just curious - what are the indications of a Variocam solenoid/actuator problem? Trying to troubleshoot my issue of a "misfire" when accelerating through ~2700 rpm.

Macster

Here's what I recall from when the passenger side solenoid/actuator proved to be bad:

One second the engine was running just fine the next it was not.

As I arrived at my office after an uneventfull 30 mile drive mostly at highway speeds the engine developed an odd idle condition.

One moment the engine was idling at normal idle speed then it dropped to around 500 rpms (by the tach dial/needle) then almost no sooner did it reach 500 that it climbed again to the normal idle rpm and this cycling repeated over and over again, at least for the few minutes I let the engine idle.

Gave the engine some throttle and it picked up rpms ok and sounded ok. No scary noises. (I was probably whimpering though...)

No other symptoms, Oh, the CEL was not on.

I connected my trusty Obd2 code reader and checked for DTCs. Even though the CEL was dark I thought it might be dark because the bulb had burned out.

But the CEL status was 'off'.

Then I read pending DTCs and there was one, P1341: 174 Camshaft Adjustment, Bank 1 - Signal Implausible, 174 Camshaft Adjustment, Bank 1 - Below Limit, 174 Camshaft Adjustment, Bank 1 - Above Limit.

I used the reader to clear DTCs, though there was no current DTC this also cleared the pending DTC.

Then I shut off the engine and restarted it and upon restart and idle the rough idle symptom was no longer present and the engine still sounded ok.

Decided to risk it and drove the car home and did so without incident.

Next business day drove the car 1.5 miles to the dealer. The idle was a bit rough upon startup -- probably because fuel trims reset after I cleared the code -- but nothing like it was the day before.

I can add that I after the initial engine roughness symptom appeared I also for a bit viewed the short fuel trim readings and noticed the #1 bank's fuel trim was quite different from #2 bank's fuel trim.

Generally when I have viewed these they pretty much are the same.

When I mentioned this to the tech when the car was in for repairs he said that is to be expected. The DME was attempting to vary the fueling to that bank to get the sensor readings it expected but of course failing because the VarioCam solenoid/actuator were not working properly and the the valve timing that should have been in effect was not in effect.

Misfire error codes never appeared in my car's case. I do not know if I had continued to drive it would they have appeared.

And there may be other failure modes of the VarioCam hardware that could result in misfires. I'm not aware of any but that doesn't mean they do not exist.

Sincerely,

Macster.

bmuhonen

Thanks for the reply Macster.

I'm taking the car (09 C2S) in next week in an ongoing attempt to solve what I believe must be a Variocam related issue (a sometimes harsh bump and audible "pop" when accelerating through ~2600 rpm). I plan on asking them to hook up the PIWIS and manually actuate the system on each side (I believe I read on this forum that this is possible). Are there any other troubleshooting procedures that you might recommend? All other engine operation appears normal, with the exception of a slightly rough idle , and no codes appeared last time it was on their computer.

Thanks for your time

Macster

The valve timing and lift (courtesy of VarioCam Plus) is closely monitored by the DME and it is rather good a flagging any problems. IOWs, the CEL would be on.

The harsh bump is probably the engine stumbling during acceleration. The momentary stumbling (due to some brief drop off or even cut out of power) is attenuated by the momentary drop off/interruption in acceleration.

Still it is not normal. The engine should pull smooth from idle to redline and upon an upshift and continued acceleration -- when it is safe to do this -- resume pulling smoothly.

Regardless, it doesn't hurt to have the tests done that you want to do. Were I in your shoes I'd have them done.

Or you might just describe the behavior, note under what conditions it appears, and ask the techs what diagnostics they'd recommend?

I'm told, and my printed sources agree with this, there are ways to exercise the VarioCam Plus system under PIWIS2 control and to monitor various engine sensors (O2 sensors for instance) to confirm the VarioCam system is working properly. Some of these tests can be done in the service bay. Others require two techs and the car out on the road. If the service bay tests do not turn up anything you might push for the road test. At least ask about any road test and listen to what the techs have to say.

Also, the system might be ok, but one of the individual components -- like a lifter -- might be going bad, which can possibly account for the behavior you report.

Oh, other trouble-shooting procedures... well, the techs being experienced when they hear the details of the symptom should mentally review what can possibly account for the symptoms and advise you what tests/checks are appropriate.

Are plugs due to be replaced?

Fuel filter?

Air filter?

Did the symptoms appear out of the blue, or after some work/servicing was done on the car?

Have you been running a top tier gasoline? Buying from a busy station?

How is your driving style? Oftentimes the techs tell me these cars just don't get driven hard enough -- subjected to higher loads and higher rpms -- and this can lead to a build up of deposits that can affect air flow into the combustion chamber and affect the engine's performance, although the symptoms are not so dramatic.

No need to answer the above questions just think of answers and be prepared to share with the techs.

If you can be sure to provide a follow up. I would very much like to know what's going on.

Sincerely,

Macster.