Here's the deal......
Back in May of this year my engine developed a nasty noise. Long story short, it ended up being a defective water pump bearing. During the process of finding the issue I replaced the cam chain adjuster. I figured at 190k+ miles it was a reasonable PM to perform. So the timing chain adjuster was replaced along with a complete TB service (TB, water pump, TB tensioner, idler pulley etc). The OEM timing chain adjuster was still functioning OK but upon removal the wear pads had some significant wear. Life was good for three months.
Then in August I started getting a P0011 and a P0012 indicating an over-advanced or over-retarded intake cam. Since I never had these codes in the previous 190k+ miles I had to assume a defective cam chain adjuster. I contacted the supplier and had the adjuster replaced under warranty. Life was good for another three months.
Then last Friday I put ~600 miles on the car. I stopped at the Hospital on the way home to visit a coworker and when I went out and started the car I was graced with a CEL for a P0011. I reset it and on the trip from the Hospital to home (10 miles) I was the graced with a P0012. (over advanced / over-retarded cam position codes). Since then I no longer get a P0011/0012 but I do get a daily P0340 and I have a bad idle with reduced vacuum. My speculation is that the cam adjuster is now stuck in the middle between full retard and full advance. Consequently the ECM doesn't know what the hell is going on since the cam position sensor can't tell if the cam is at full advance or full retard. So it gives me a P0340 position sensor malfunction code since it doesn't know what else to do.
I should mention that I had a spare cam position sensor and changing it made no difference. The cam position sensor is getting a 5v trigger signal as it should and the cam adjuster solenoid is getting a 12v activation signal as per spec. I checked the resistance on the OEM solenoid activator as well as the replacement solenoid activator and both were at 13Ω resistance. According the the Bentley it should be between 5-8Ω at 20°C. Technically it is out of range but when I apply a 12v signal I can hear both of them activate so I don't think that is an issue.
So what are the chances that I received two defective cam adjusters? Although it seems highly unlikely I am running out of things to check. So here is what I am going to do this weekend. I ordered and received replacement wear pads for the OEM cam adjuster. Tomorrow or Sunday (weather permitting) I am going to replace the replacement cam adjuster with the OEM one and see if the problem goes away.
So wadda you think?? Will it fix the problem? Do I have some other issue that I need to address? I'm getting pretty tired of replacing the same part over and over again. All suggestions are appreciated. Bad adjuster? Lightning strikes twice in the same place or something else going on?
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