Camshaft adjuster questions

[chubert]

Hi,

Car is a base 1999 Boxster.

At a recent autocross event I believe the bank 2 cam adjuster was stuck in the "on" position even at idle. After a run I had a rough idle and a P1524 code and some misfire codes. Car idled rough but was fine at higher RPM. It stayed like this for a few restarts and after a 1.5Hr cool down. Water temp was fine and no oil lights etc. Castrol 5W40 with 800 miles is in the engine.

When I went to leave it seemed to clear itself after the car was running for 2-3 minutes. It was fine the next day as well. No more codes. I have put about 60 miles on it since.

When I connect my Durametric to it I can reproduce the symptoms by activating the adjuster manually and it seems to go on and off properly.

What RPM the adjuster typically activate? Is it a multistage adjustment? Can I see this activate when driving with durametric?

Is there anything other than a failing adjuster/solenoid that can cause this? Low oil pressure? excessive heat?

Another data point is I can not seem to get an accurate Cam deviation reading. Bank 1 is 0.0 and bank 2 is 3.0. This never changes so I suspect it's not a real reading. This has been the case for several years and at least 7500 miles but the car has been running fine. My Autel MD802 shows no cam deviation data data at all.

Thanks

[Gelbster]

The Variocam on my 2001 S actuates progressively and reaches full advance before 3000 rpm.But it must be a warm engine.
In my limited experience ,I have noticed other Boxsters (inc mine) have more deviation on one bank than the other. Weaker/worn chain tensioner on one side??
In theory the solenoid can fail intermittently(Connections?) or gradually and the oilways in the actuator can plug with debris.That may be your issue?
You might want to confirm the basic timing of the cams is correct (green plugs) ?
If you need a more comprehensive discussion, it was covered in detail on Renntech recently.But try the simple diagnostics first in my experience with Variocam.There is an Ohm test, a click test, and others that involve fabricating test harnesses .Do every test you can find before deciding to remove cam covers ! For example do a road test & use a passenger to monitor with Durametric live data for Angles in Actual Values on both Banks simultaneously.You can log the results.

[chubert]

Originally Posted by Gelbster

The Variocam on my 2001 S actuates progressively and reaches full advance before 3000 rpm.But it must be a warm engine.
In my limited experience ,I have noticed other Boxsters (inc mine) have more deviation on one bank than the other. Weaker/worn chain tensioner on one side??
In theory the solenoid can fail intermittently(Connections?) or gradually and the oilways in the actuator can plug with debris.That may be your issue?
You might want to confirm the basic timing of the cams is correct (green plugs) ?
If you need a more comprehensive discussion, it was covered in detail on Renntech recently.But try the simple diagnostics first in my experience with Variocam.There is an Ohm test, a click test, and others that involve fabricating test harnesses .Do every test you can find before deciding to remove cam covers ! For example do a road test & use a passenger to monitor with Durametric live data for Angles in Actual Values on both Banks simultaneously.You can log the results.

Thanks for the ideas. I wonder if the 2.5 is an on/off mode or variable like yours. I cant seem to get Durametric to read cam deviation. It always says 0 degrees for bank 1 and 3 degrees for bank 2. I wish I could get a good reading.

I am pretty sure I don't have a hard timing issue like a skipped tooth as it's running fine now. No codes any more. It was a temporary thing and "fixed" itself after about 3 miles.

It seems to act properly when I manually activate the actuator on and off via durametric so maybe the solenoid didnt release or the actuator was stuck somehow. Also, I just had the oil pan off 2 days before to add an X51 baffle and it was 100% clean, no debris.

I also suspected the MAF but wouldnt that affect all cylinders? This was just bank 2 and it threw cods on all three cyl at the same time. At this point it's not failing anymore so I have to wait till it acts up again.

I just wanted to get a better understanding how it works so I can better diagnose when it happens again.

[JFP in PA]

Originally Posted by chubert

Thanks for the ideas. I wonder if the 2.5 is an on/off mode or variable like yours. I cant seem to get Durametric to read cam deviation. It always says 0 degrees for bank 1 and 3 degrees for bank 2. I wish I could get a good reading.

I am pretty sure I don't have a hard timing issue like a skipped tooth as it's running fine now. No codes any more. It was a temporary thing and "fixed" itself after about 3 miles.

It seems to act properly when I manually activate the actuator on and off via durametric so maybe the solenoid didnt release or the actuator was stuck somehow. Also, I just had the oil pan off 2 days before to add an X51 baffle and it was 100% clean, no debris.

I also suspected the MAF but wouldnt that affect all cylinders? This was just bank 2 and it threw cods on all three cyl at the same time. At this point it's not failing anymore so I have to wait till it acts up again.

I just wanted to get a better understanding how it works so I can better diagnose when it happens again.

Yours is a VarioCam system, which is a simple "on/off" single advance system; there is no "progression" as is found in the later VarioCam+ system. These systems are known to malfunction if the rather small oil passage gets blocked by a small chunk of debris, which is probably what happened in your case. If it does not return, you should be fine.

[chubert]

Originally Posted by JFP in PA

Yours is a VarioCam system, which is a simple "on/off" single advance system; there is no "progression" as is found in the later VarioCam+ system. These systems are known to malfunction if the rather small oil passage gets blocked by a small chunk of debris, which is probably what happened in your case. If it does not return, you should be fine.

Thanks for the positive thoughts! I appreciate the response I hope it was just a temporary thing. Do you know when it activates? RPM or throttle position or some combo of other things?