S4 Cam Timing Problem/Issue/Mystery

[Kappy]

I am seeking help diagnosing a cam timing issue with a 2004 S4 (134,000 miles). I bought this car from an independent dealer with a check engine light and OBDII code P0345 (camshaft position sensor bank 2). This was a disclosed issue by the dealer and I knew about it when I bought the car.

The history of this issue is that the dealer bought the car wholesale with a hesitation/sluggishness at low rpm and an obvious power bump/surge around 3,500 rpm but no CEL. The check engine light then came on with code P0345. The dealer was hand rotating the motor preparing to check the cam timing when a timing chain guide snapped preventing the motor from turning at all. The dealer pulled the motor and replaced all the chain guides and tensioners thinking that this would have solved the cam timing CEL code. When the car was reassembled, it had the same P0345 code and low rpm sluggishness it had before the timing chain guides broke and the guides and tensioners were replaced.

The current symptoms are a sluggishness at low rpm and a surge/boost in power around 3,500 rpm. This is a consistent condition but, sometimes, at a cold start it does feel as if there is more power at lower rpm (this could be my imagination). The only code is P0345. I replaced the left cam position sensor. I checked the resistance on both control housing solenoids and they were both 10.7 ohm.

The dealer I bought the car from suspects the problem is either a problem in the mechanical cam adjuster or a jammed or malfunctioning control solenoid based on similar issues with the Audi 3.2 V-6. After reading about this motor, I suspect that it could be the mechanical adjuster on the left side. However, it seems from what I have read about the experience of other S4 owners that a problem with the mechanical cam adjuster usually produces misfiring and additional codes that I am not getting. My engine actually idles very smoothly and the power delivery above 3,000 is consistently smooth.

I have theorized that the electric solenoid may be stuck in one position and this causes the mechanical adjuster to be always in the same position. I am considering trying to apply 12 volts to the control solenoid to free it up if it’s jammed. I am a little hesitant to do that since I don’t want to break a working solenoid if that’s not the problem. Has anyone had a jammed solenoid or used 12 volts to break a jammed electric solenoid free?

I appreciate any insight you can provide.

[bmwpower603]

Sounds like an adjuster. (Mechanical adjuster) If it was both banks. It would be a guide

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[emilio]

hrm, i'd think a solenoid problem would throw a code specific to that solenoid. it seems there are a lot of solenoid/valve codes out there, so i imagine every one is monitored. i'm not sure if a no-code problem would be more likely than a bad mechanical adjuster that doesn't cause misfiring.

i'm pretty sure all engine solenoids can take straight 12V, so i don't see a problem in trying it. maybe give the area some taps with a mallet?

- emilio

[ZimbutheMonkey]

Agreed that it's likely the adjuster.

The locking pin wallows out and it can't lock itself into position.

Have you pulled any logs to see where the cam is positioning itself during operation.

[icanfly]

Agreed that it's likely the adjuster.

The locking pin wallows out and it can't lock itself into position.

Have you pulled any logs to see where the cam is positioning itself during operation.

Agree. this sounds like mechanical adjusters and ultimately with those miles, I'd be willing to bet you're past the point of no-return with those wallows.
I've got good sprockets (OEM used - no wallow on one, tiny wallow on the other - Id reinstall in my own car with no worries had I not upgraded) with full mechanical adjuster gasket kit for sale - PM if you need parts to solve your problem and don't want to spend big on new gear.

[bmwpower603]

Agree. this sounds like mechanical adjusters and ultimately with those miles, I'd be willing to bet you're past the point of no-return with those wallows.
I've got good sprockets (OEM used - no wallow on one, tiny wallow on the other - Id reinstall in my own car with no worries had I not upgraded) with full mechanical adjuster gasket kit for sale - PM if you need parts to solve your problem and don't want to spend big on new gear.

Might be a good time to replace your plastic main engine guide. Make sure and use the one of the Rs4 that JHM sells in their timing kit.

[icanfly]

Might be a good time to replace your plastic main engine guide. Make sure and use the one of the Rs4 that JHM sells in their timing kit.

This... ultimately, just get their kit and do the job. You'll thank yourself for fixing your car. It will feel awesome, and you wont stress everytime you put the key in the ignition...