Chasing a P0014 (and maybe my tail?) on a 2001 V70XC Topic is solved

[- Pete -]

I decided to roll the exhuast cam back one tooth, back to where it was initially. I mean if it ran that way before I "advanced it" 1 tooth, no harm. I figured if the code it's generating is that the cam is too far advanced, advancing it further isn't doing anything good. So I set it back to where it was.


After rolling the exhaust cam back 1 tooth, it looks like actually the intake cam is off by a tooth, or part of a tooth, or am I delusional?

Considering that, is it possible that since the intake cam has NO sensor on it, that it is actually the cam that is off and generating the P0014?

Am I risking anything by rolling the intake cam back one tooth to where it appears it might align closer to "spot on"?

Right now, with the exhaust cam rolled back to where it was before I advanced it, it starts & runs, but loping idle is still present.

In addition, I felt the VVT hub for play, and there is a miniscule amount, not as severe as this guy in the video below, but there is a tiny bit.


Here are all my marks:

Ok, that was a couple days ago.
So I got my parts today, I put in the new solenoid & BCV/TCV, started the engine briefly without the serp belt on & it ran ok, then the loping idle began again.

I need a little advice. Looking at my timing alignment marks, do you think I should roll the intake cam sprocket back 1 tooth?

[- Pete -]

Well, as with all of my Volvo-related tasks, I'm going to hold off on feeling elated for at least 1,000 miles. I am experiencing a little relief though. After re-timing the intake cam (rolling it back counterclockwise 1 tooth) & installing the new VVT solenoid (& turbo BPV), unhooking the batt & touching the pos to neg for half a minute or so, I fired it up, had misfire codes on cylinders 1-4. Kinda puckered me up a bit. Even though it was running smooth, for once, I shut off the engine, restarted the engine and my software after clearing codes. Ran smooth enough that I decided to drop the car down & drive it & see what the real-world numbers looked like on the logger. Boost was back, throttle response & power was back (to what I'm used to with non-code producing XC70's), Still had/has a little "lurch" type feeling around 1200 rpms, but ZERO codes being thrown. I drove it for 20 minutes or so, re-scanning every 2 minutes or so for codes. Will do several start/stop cycles to verify & report back here with anything new.

So I've now driven it for at least 45 minutes, even went and got a carwash. I dumped & flushed the trans after 1/2 can of Trans Tune & then drove it another 20 minutes.
I detect a couple stumbles here and there, but overall it behaves like you'd expect a healthy XC70 to.
I can't say whether the new solenoid did the trick, or re-timing the intake cam, a combo of the two. I also installed a new Turbo Boost Pressure Valve, but I doubt that had anything to do with it. Went over all the vacuum lines & re-secured some rubber hose that was half pulled off a nipple near where the intake pipe heads into the turbo.
What I do know is it runs perfect now & I feel like it's pretty safe to say that an intake cam that's too far advanced on an exhaust-VVT-only turbo motor can trigger an exhaust cam timing over-advanced (p0014) code.

Thanks for your help!
I'll post back with an update every couple thousand miles or so.

- Pete -

[abscate]

I decided to roll the exhuast cam back one tooth, back to where it was initially. I mean if it ran that way before I "advanced it" 1 tooth, no harm. I figured if the code it's generating is that the cam is too far advanced, advancing it further isn't doing anything good. So I set it back to where it was.


After rolling the exhaust cam back 1 tooth, it looks like actually the intake cam is off by a tooth, or part of a tooth, or am I delusional?

Considering that, is it possible that since the intake cam has NO sensor on it, that it is actually the cam that is off and generating the P0014?

Am I risking anything by rolling the intake cam back one tooth to where it appears it might align closer to "spot on"?

Right now, with the exhaust cam rolled back to where it was before I advanced it, it starts & runs, but loping idle is still present.

In addition, I felt the VVT hub for play, and there is a miniscule amount, not as severe as this guy in the video below, but there is a tiny bit.


Here are all my marks:

Ok, that was a couple days ago.
So I got my parts today, I put in the new solenoid & BCV/TCV, started the engine briefly without the serp belt on & it ran ok, then the loping idle began again.

I need a little advice. Looking at my timing alignment marks, do you think I should roll the intake cam sprocket back 1 tooth?

Great news! Added solution to title for search, good sleuthing.

[- Pete -]

Next step for me is to take the plunge & finally purchase Vida/Dice!

[DeadEric]

Sounds like your cam phaser is advanced and you have a bad vvt solenoid by what you said before you cleaned it. Being a device that uses electricity to move it mechanically, ohm checking it is half of the equation. If you'd like I can explain how it works in detail but I'm trying to keep this short. Cleaning it the way you described could not only damage the solenoid but allow the gunk to flow past the screens and into the phaser.

Not being familiar with P0014 this may or may not fix your problem. You might have to find a shop that can do an accurate cam/crank correlation test.

You also mentioned that it ran better off idle. This is normal, higher rpms is when the phaser would activate and advance (usually with load.)

Lastly, with the P0014 setting immediately after code clearing, the non continuous monitors will not run. Meaning other codes will not be tested or set until this is fixed and a drive cycle is run. Cat and evap test are usually the last to run.

[abscate]

Vida will actually map the cam position for you and tell you exactly what is going on.

I would have thought that the cam error would be triggered only by the sensor position but maybe the ECM algorithm is more complicated than that.

I think I’ve read here that up to three notches on the cam sprockets are safe in terms of interference so bumping a notch or two is safe.

[- Pete -]

Sounds like your cam phaser is advanced and you have a bad vvt solenoid by what you said before you cleaned it. Being a device that uses electricity to move it mechanically, ohm checking it is half of the equation. If you'd like I can explain how it works in detail but I'm trying to keep this short. Cleaning it the way you described could not only damage the solenoid but allow the gunk to flow past the screens and into the phaser.

Yes, please expound, you seem pretty knowledgeable. What part of MN are you in?
My original solenoid gasket was the non-screened type, and my original solenoid was flowing clean when I reinstalled it.
I don't know if you watched the short clip I linked with the guy that had the play in his VVT hub, but I had a fraction of that amount of play. So, yes, I agree with you that the VVT hub (aka phaser?) is probably going to be the next piece to fail/replace. I assume that since this part isn't in perfect mechanical shape that IT is responsible for the "lurch" in power felt around 1,200 rpms.

I don't really see how a hall effect sensor like the cam position sensor(s) can go bad, but I'm sure it has happened. De/polarization.

Again, I really can't say exactly which component it was (or combination of) that led to my resolution but I'm happy & just kinda going with it for now. Replaced VVT solenoid, retarded intake timing 1 tooth, replaced BPV, re-secured vacuum line to nipple on intake pipe that goes into turbo, changed oil.

You also mentioned that it ran better off idle. This is normal, higher rpms is when the phaser would activate and advance (usually with load.)

Lastly, with the P0014 setting immediately after code clearing, the non continuous monitors will not run. Meaning other codes will not be tested or set until this is fixed and a drive cycle is run. Cat and evap test are usually the last to run.

I do think that the cat was partially occluded when I first got the car. The scanner did show a cat code. This would make sense seeing as the car had been driven a while with the dead #5 ignition coil, on top of the fact it had been driven a year or more with the intake timing off. In fact, the exhaust note actually sounded different than our other XC's/muffled or plugged up sounding prior to any of my successful repairs/trials. The first few drives I took it for (after making successful adjustments), when I'd get back in the garage & pop the hood the exhuast was really really hot. Gradually the temp would come down & engine temps actually came down also from what they had been previously (were ~190 H2O temp, now runs around 182-3). After having driven the car maybe 1-1.25 hours the exhaust note has now changed, as in normalized, sounds just like any untampered with XC70. So strange. So I'm guessing with enough heat being generated & the engine running as it should the cat has sorta gotten cleaned out.

Vida will actually map the cam position for you and tell you exactly what is going on.

I would have thought that the cam error would be triggered only by the sensor position but maybe the ECM algorithm is more complicated than that.

I think I’ve read here that up to three notches on the cam sprockets are safe in terms of interference so bumping a notch or two is safe.

Since there's not a sensor on the non-VVT cam (intake, in my case), yeah, they must account for it based off the exhuast cam's position.
Well I can attest that even being off on my exhaust AND intake cams by 1 tooth each (at the same time!) no piston to valve contact was made! Thank God!

[DeadEric]

Not specific to Volvo but generally how VVT solenoids work.

The VVT solenoid uses an electromagnetic coil to move a shaft inside. The shaft opens and closes ports to allow oil to fill or drain from the cam phaser (or vvt hub, the part that changes the timing of the valves without changing physical timing.) The ECU commands the VVT solenoid with a pulse width modulation duty cycle. (Turning it on and off very fast, like a 1000 times a second fast.) By raising the duty cycle (amount of on time, or on for longer) you make a stronger magnet and move the shaft further. Moving the shaft further allows more oil into the phaser and the cam shaft timing shifts further.

Ohm checking the solenoid, you can see if the magnet coil windings are shorted or open. However that doesn't tell you if the "gunk" has worn the shaft or gotten to places it shouldn't and it no longer moves correctly.

Car manufacturers use VVT to reduce emissions during idle and cruising (low power demand) but you still have the ability to make power when needed.

Hope that's helpful.

I live in Minneapolis.

[davep84]

I know this was 2 years ago but did you figure out what was going on?

[- Pete -]

It was a combination of timing being just slightly off and (what I believe to have been) a flaky and/or gunked/sludged up exhaust VVT solenoid. What’s weird is that after I’d cleaned it as best I could (2001’s had what they call a “non-serviceable” VVT solenoid that didn’t come apart), the bench test showed it seemed to behave in a manner I couldn’t find a whole lot of fault with. Even comparing it to a newer “rebuilt” serviceable-type VVT solenoid I couldn’t detect much difference. It even ohms within what I’d call an acceptable range.

Regardless, between the new solenoid and (after several attempts) perfecting the timing, all symptoms and codes of that nature have gone and not returned.

The original “non-serviceable” VVT solenoid is top-right in the photo.

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