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Most vvt systems have a locking pin in the pulley which is used to hold the cam during start up while oil pressure is low, these can become sticky on some engines.
There will also likely be a small gauze type oil filter at the solenoid which can clog on some engines and cause vvt issues too.
Thanks Andrew. Decided to stop whining and just do this right - pulling out the solenoid now. I bet it is stuck in the advanced position, which is why the car runs ok above 3K rpm.
A stupid question that is probably really obvious - I have all the bolts out for the valve cover no problem, can deal with the AC wire, but how do you move the wiring harness out of the way without breaking something? The bolt is out (at arrow) and I can pull it up an inch or two, but if you have to lift the valve cover straight up so as not to break the fingers on camshaft, that is no where near enough. That whole black plastic guide blocks the valve cover - are you supposed to cut all the zip ties in the harness and remove the plastic part? There are lots of DIY guides but everyone just says to "move it out of the way"...how hard can you push on this thing without something breaking? Thanks.
Just cut the zip ties and remove that plastic housing from between. Removing the large wire going to jump start terminal is also an option, not absolutely necessary but helps.
Looks like in this case the filter is part of the solenoid, I would also make sure the gallery it goes into isn't sludged up
Yeah, there is a YouTube video from some Russian mechanics that show the parts of it and how to clean it pretty well. I'll probably take photos and post them.
Originally Posted by hopsis
Just cut the zip ties and remove that plastic housing from between. Removing the large wire going to jump start terminal is also an option, not absolutely necessary but helps.
Thanks hopsis - I was just about to cut them and then I though since nobody I read mentions cutting them maybe I'm missing something obvious. Will do this tomorrow.
I don't recall this exactly but I think that the strainer design was changed mid-production at some point. Older ones had that strainer integrated to the solenoid and later models have a separate strainer. Keep that in mind when You get the solenoid out, don't just rip the strainer off, it may be it wasn't meant to be removed if You have one the earlier engines.
Early 2003 - 2004 V8 Cayennes had a plastic strainer embedded in the camshaft housing.
If I recall, even with the solenoid removed you couldn’t remove the strainer.
Removal of the camshaft housing was required to remove this strainer from under the housing.
From 2005 a metal oil strainer was adopted.
This one could be easily removed from the housing for cleaning using a small magnet once the solenoid was removed.
Work got in the way once again, but got the valve cover off and solenoid out this morning. I hooked a fresh 9 volt battery up to it, but couldn't really hear much of a click from it. Cleaned it out for a while, but still not getting any sound from it when energized. The sensors from both banks read about 11.3 ohms, and I get a spark when I connect them, so I think the coils are OK. I will let them soak for a while and see. Mine are the kind with the plastic strainer down inside it seems.
I replaced a very similar looking solenoid in my old Boxster. Granted it was a 2010.
After replacing, I fiddled with the old one and after lots of brake clean, it began engaging in the test bench with a 12v source.
I gave it to a fellow PCA member who I think still doesn’t have issues with it.
And hopefully that is exactly what just happened for me as well! So when I first cleaned it and put power to it there wasn't much of any kind of sound, but going with the theory that it stuck in the high rpm (engaged) position, there wouldn't be any more it could engage anyway, so I pumped it full of MAF cleaner and beat on it a bit with my hand and sure enough it started clicking when I applied power to it, and sounds just like the one on YouTube. So I'm calling this likely the problem and going to start putting this side back together.
Now I can totally see what happens is I start it and it will idle fine, but now not run at high rpm because the other side is sticking in the low rpm mode - when I put power to the other bank solenoid (which is still in the engine) I can't hear anything much. So the thing to do would be to take the other bank apart and clean that one as well. That is the side that the valve cover is leaking, and I have new gaskets already anyway, so I guess that is next.
Well that could have gone better. The solenoid was the problem, but cleaning it was not the solution. It ran great for a few minutes, but after revving it a few times it stuck in the engaged position again. Damn. New ones are like $400 USD, and I would have to both if I decide to keep going with this. Maybe soaking it for a day in solvent would do a better job, I don’t know. And no one is parting out an engine locally right now. Decide tomorrow.
I guess they would be available on ebay. I have one spare solenoid, it's here in Finland though so not exactly local.
Originally Posted by Jfrahm
You could try ultrasonic cleaning.
Thanks guys - the jury is still out it seems. I started it up this morning to run some logs with the PIWIS and it ran perfectly fine. Neither solenoid was sticking and it revved it up and down to generate up to 40 degrees offset and both sides showed a really good advance/retard profile. So I pulled the valve cover on the other side and just got the other solenoid out, and on the bench it seems fine. I think I will clean it even though it is working, put the new valve cover gasket on that side, do an oil change and see how it runs.
Since it did stick once last night after cleaning I am not sure I would ever trust it so much on trips into the mountains with these solenoids, but Jfrahm found a set on eBay for a reasonable price – I think I should pick those up anyway. OK, time to go reassemble.
Update: got it all back together and it is running, but not running great like it was before. No more cam problems but there is a dreaded ticking sound now - hopefully not piston slap or a bent valve and just a low pressure lifter. Plus it has many misfires that need to be blown out I guess. Going to change the oil tomorrow and give it a road test.
So I suppose this is the end of this saga - both camshaft solenoids were cleaned and seem to be working now. I drove it for a few hours today and no return of the problem. For future readers dealing with this, only things to note is that if when logging the camshaft angles you see some kind of saw tooth pattern on the offending camshaft, even if it is at -40 degrees, the sensor could be fine and reading things correctly. Also, after cleaning the solenoid on both banks, even though they worked fine on the bench, and I tried to fill them with oil, they still stuck the first time the engine was run. But only once, and after (I assume) they filled properly with oil they were fine. The disrupted oil flow in my case seemed to cause a lifter to have a hard time pumping back up and there was a ticking sound for quite a while afterwards, but that went away.
Although the engine is idling and running smoothly now, it is starting to sound a bit like an old engine - faint clunking sounds from deep inside that weren't there 50,000 km ago. But I am just going to drive it now and see. After I fix the plastic hoses that broke in the process. Who knows how long any of us have anyway...! Thanks to all for the help.
02-13-2022, 07:08 PM
