Variocam Issue? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

freserf · 12-08-2020, 11:18 AM

The previous owner of my 1997 Porsche Boxster listed the following problem for the engine. "Valve train noise at high rpm. Possible variocam solenoid bad. No issue at low rpm." The following codes showed up when I revved the engine or were already set when I hooked up my reader. P0300, P0301, P0302, P0303, P0341, P1319, P1313, P1314, and P1315. I did experience the misfires without driving the vehicle and I understand what they mean ... trouble with bank 1 misfire and possible camshaft sensor issues. The emission codes are just warnings because of the misfires. Stop driving to prevent damage. So far I have checked and confirmed good camshaft sensor and compared both variocam solenoids at about 12.7ohms with good voltage to both. I can also hear them clicking when testing with my power supply. Having worked with many types of solenoids, I know they can test fine, but not really work well as they age. The car has 86000 miles and the documented history is not the best. I have also read through many posts from various sites related to this similar issue and still do not have an "Aha", idea to run with. Spark plugs were extremely worn and coils looked good ... and there was no signs of broken plastic parts or metal in the oil or filter.

I am leaning towards timing chain wear or more likely tensioner pad wear even though I haven't seen evidence so far. I want to pull bank 1 side head cover and visually check the tensioner pads. Do I need the special P253 tool or just something to hold the ends of the camshafts in place in order to pull the cover. I don't mind being a perfectionist, but the KISS method works best for me.

Lastly, there is a loud rattle for about 1 second on start up and read this may be normal and using a different grade oil may reduce this ...

Is it possible due to failing IMS since it is driving bank 1 to cause these symptoms?

Just want some input from those who have experienced similar situation. Thanks for any input and have a great day.

BYprodriver · 12-08-2020, 12:16 PM

Be more optimistic, you are having misfire codes Install new spark plugs & see what happens after clearing all the codes. If one cylinder misfires it can cause the next cylinder to misfire. Be sure all coil leads are properly installed.

freserf · 12-08-2020, 03:12 PM

Thanks for the reply ... just finished replacing Bosch FR6LDC with Bosch FR7LDC+. All were very worn but only bank 1 misfires so far ... see attached photo.

I can only go on what information was given and what I have read so far ... this is my first Porsche project ... so there is a large learning curve. If it turns out to be just some badly worn spark plugs to have it run smooth, that would be great. She wasn't treated well and I enjoy the challenge.

JFP in PA · 12-09-2020, 06:19 AM

From the looks of the oil on that plug, your plug tubes are leaking.

freserf · 12-09-2020, 07:39 AM

That is an affirmative ... I was debating with myself on whether to buy a puller or just use a makeshift long bolt head to remove them and replace with the new ones that arrived this week. I can always stock my toolbox, but as I get older and hopefully a little wiser ... I've learned to adapt with what I have on hand. I am sure they are the original and unfortunately, o-rings don't last forever. Could be a little or a lot stuck though. Had any issues removing these?

szube · 12-09-2020, 10:40 AM

A T-handle boat drain plug works well to pull the plug tubes.

Jgkram · 12-09-2020, 11:13 AM

I used the long bolt head "tool" and it works just fine. Hook it behind the tubes and they pop out just fine. Good luck and welcome to our world.

JFP in PA · 12-09-2020, 11:42 AM

And, if anyone is interested, somebody in the aftermarket (Rauch and Spiegel) now makes the tubes in aluminum, totally eliminating the tendency for the OEM plastic tubes to deform and/or crack over time.............

traveno · 12-09-2020, 03:21 PM

Quote:

Originally Posted by JFP in PA

And, if anyone is interested, somebody in the aftermarket (Rauch and Spiegel) now makes the tubes in aluminum, totally eliminating the tendency for the OEM plastic tubes to deform and/or crack over time.............

Those looks beautiful. I just replaced mine with new plastic tubes. Otherwise I could try to justify buying a set of these. Maybe I’ll find a set in my stocking this Christmas. I hope!

freserf · 12-10-2020, 08:58 AM

Thanks for the replies ... I like the boat plug method, unfortunately I sold my boat about 10 years ago. I tried several different make shift tools ... the head of a carriage bolt and a set of measuring calipers slightly modified. The tubes did not want to let go so I ended up removing the outer plastic to remove the large o-ring and then they decided to let go ... I hope I did not get any pieces into the head as they were very brittle.

The Rauch and Spiegel aluminum tubes look like a great idea ... I will probably get these if I do need to remove the head covers to replace solenoid or timing chain pads. I noticed that they also sell the puller tool ... tempting, but I'll hold off unless I decide to work on future Porsche Projects.

I plan to drop the car off the jack stands this evening or tomorrow and test the engine for repeat codes.

freserf · 12-11-2020, 08:54 AM

Well ... pulled the car out of the garage for testing. Fired up engine with new air filter, fresh fuel, oil, and spark plugs. The engine codes reappeared. Misfire on bank1 with camshaft position code P0341. I did notice that the engine ran fine until the secondary air blower timed out. If I let the codes set at idle ... which is rough, I could clear them and then slowly raise the RPM's up to about 2600 when I heard the timing chain rattle. Reset the codes and was able to hold the RPM's steady at about 1850 without any misfires.

So, I would like some input on what to try next. Idle at engine full temperature is rough due to the misfire detections ... but at cold startup idle is good until secondary air timeout. Able to hold RPM's up with no misfires.

What do you guys think?

blue62 · 12-11-2020, 09:17 AM

Quote:

Originally Posted by freserf

Well ... pulled the car out of the garage for testing. Fired up engine with new air filter, fresh fuel, oil, and spark plugs. The engine codes reappeared. Misfire on bank1 with camshaft position code P0341. I did notice that the engine ran fine until the secondary air blower timed out. If I let the codes set at idle ... which is rough, I could clear them and then slowly raise the RPM's up to about 2600 when I heard the timing chain rattle. Reset the codes and was able to hold the RPM's steady at about 1850 without any misfires.

So, I would like some input on what to try next. Idle at engine full temperature is rough due to the misfire detections ... but at cold startup idle is good until secondary air timeout. Able to hold RPM's up with no misfires.

What do you guys think?

P0341 is as you know cam position sensor1: signal implausible/implausible operating range/malfunction.
You stated that you tested it.
Did you test to see if signal is getting back to the DME over the entire operating range?
If everything tests good with the Cam position sensor and wiring then I would look at Camshaft deviation and Camshaft timing on bank one.

freserf · 12-11-2020, 10:05 AM

What tool ... that is reasonable would be best to look at the signals? I only have MBII iCarsoft tool that I use with my Benz. I am able to read live data, but not much ... o2 sensors, TPS, fuel demand, rpm ... it also has o2 sensor tests that seem to be good. I guess I will find the computer (DME) and check connections and double check for bad or rubbed wires.

blue62 · 12-11-2020, 10:44 AM

Quote:

Originally Posted by freserf

What tool ... that is reasonable would be best to look at the signals? I only have MBII iCarsoft tool that I use with my Benz. I am able to read live data, but not much ... o2 sensors, TPS, fuel demand, rpm ... it also has o2 sensor tests that seem to be good. I guess I will find the computer (DME) and check connections and double check for bad or rubbed wires.

If you could get something like the Durametric or a Foxwell that reads cam deviation or cam angle. one of those would work.
I have both. on either scanner I can look at Camshaft deviation on each bank.

I can also look at actual cam angle while the car is running so I can compare one bank to the other to see if they are close to each other or are the numbers way different from one bank to the other.
That is what I would want to look at in your case with the sensor testing good.

If your tool is able to test the cam position sensor and it tests good then it is probably ok. I believe the scanner is reading what the DME sees.

freserf · 12-11-2020, 11:09 AM

Which Foxwell reader?

blue62 · 12-11-2020, 12:56 PM

I have the Foxwell NT520 PRO

freserf · 12-11-2020, 01:37 PM

Here is another symptom maybe you can help me with ... I am still not quite sure how this variocam system works. When are the solenoids activated? Does the actuator float under oil pressure when the solenoid is not activated? The reason I ask is this ... I just unplugged bank1 solenoid and now I can rev and idle without the timing chain noise as I experienced earlier. But, I still have bank1 misfires on all cylinders without the P0341.

I'll probably swap coils this weekend to rule them out for the misfire.

I am guessing that the solenoids are active from engine on to about 2800 rpm's or when demand is high? I read somewhere about the basics of the variocam system, but nothing detail related to when it is active.

Thanks for the input ... it is always helpful to learn from others.

blue62 · 12-11-2020, 02:39 PM

Quote:

Originally Posted by freserf

Here is another symptom maybe you can help me with ... I am still not quite sure how this variocam system works. When are the solenoids activated? Does the actuator float under oil pressure when the solenoid is not activated? The reason I ask is this ... I just unplugged bank1 solenoid and now I can rev and idle without the timing chain noise as I experienced earlier. But, I still have bank1 misfires on all cylinders without the P0341.

I'll probably swap coils this weekend to rule them out for the misfire.

I am guessing that the solenoids are active from engine on to about 2800 rpm's or when demand is high? I read somewhere about the basics of the variocam system, but nothing detail related to when it is active.

Thanks for the input ... it is always helpful to learn from others.

If I understand the system correctly: When the solenoid activates it exposes oil ports which allows oil pressure to force the Variocam actuators outwards against the cam chains. Thus changing cam timing. I think this happens at around 1500-1800 RPM then it kicks back out around 5000 RPM.

If you do a search here on the forum I think you could find a more detailed explanation then the very brief one I have given. You should also be able to find the precise RPM range that the system operates in as well.

freserf · 12-11-2020, 04:09 PM

Thanks ... appreciate your feedback.

Homeoboxter · 12-11-2020, 05:54 PM

Yes, the changeover takes place at 1500 rpm, then it goes back to default at 5500. The actuators moves to the opposite direction, one is pressing down the chain toward the crankshaft while in the other bank the actuator presses the chain toward the valve cover, this way the intake cams will be advanced by 25 degrees. Check out this video and the descrioption, this will give you an idea how it works:
https://www.youtube.com/watch?v=xmNduI2lRbA&t=10s

If you disconnect the solenoid the CEL should come up and the car should become sluggish.