Camshaft CVVT solenoids and sprocket questions - P2 5 cyl engines Topic is solved

[scot850]

I had (and still have) an issue with the 02 XC70 I helped to survive with the a cam error that I have not been able to fix.

I also have a cam solenoid issue with an 06 S60 2.5T AWD I help to maintain.

I know the cars all have a cam position sensor (on the early 02 turbo XC70 just on the exhaust side), and I may be wrong, but I think there is only one on the exhaust side on the later P2 turbos too.

Both have CVVT solenoids on the exhaust side, the 03? and on, on both the inlet and exhaust side.

Do all the cars with cam solenoids have vvt hubs of some sort? Looking at Volvo parts sites they call the part between the cam sprocket and the cam a 'pulley'. Are these in some way oil filled and what the solenoid alters via the pulley with oil pressure variation?

Looking at pictures of the 'pulley' it just looks like it has bearings in it a bit like an axle bearing. I assume this is to allow them to move in some way?

Both of these cars have cam issues. The 02 with a cam position error and the 06 S60 with a cam solenoid error message.

The 02 has had the cam position sensor changed out but nothing else. I did check the solenoid resistance and it is in the region I would expect it to ne in the 2-4 ohm range. The only thing I have not checked myself (due to lack of access) is it had a cam/timing belt swapped just prior to me working on the car. I want to check it to ensure it was fitted correctly and not a tooth out. Assuming it is fitted correctly then the only other issues are possibly the cam solenoid (I think but need to check if I have swapped it) and the cam sprocket.

I have seen mention of the cam sprocket 'pulley' having issues. How do you check and verify if it is good or bad?

On the 06 it keeps giving a code of P0027 - CVVT solenoid error, exhaust side. The solenoid was swapped due to the original on the car aftermarket one with a leaking solenoid to valve body fitting. It was swapped with a spare used one off my shelf. Now I could swap this with another and see if the issue recurs. I know the belt was fitted by my ex-Volvo mechanic buddy, possible it is incorrect, but unlikely. He has fitted 3 for me with no issues.

Is there any way to check any of this, saw with Vida and live data?

Thanks,

Neil.

[jonesg]

vida can do a reaction test, it will show if the cam is reacting to slow and give cause suggestions.

[scot850]

Thanks for the input. I will have to take the time to try this.

Neil.

[volvolugnut]

I understand dirty oil can clog the filter in the solenoid.
This link has great details on the VVT operation and cam pulley setting.
viewtopic.php?p=677983&hilit=vvt#p677983
If you use the cam lock device properly, set the crank shaft and cam shaft marks correctly, and attach the exhaust pulley as described you should be properly set.
volvolugnut

[abscate]

You can look at the cam flank angles in Vida or a good scanner and see if they are behaving

All Volvo cams with a solenoid , or “ reset valve” have an oil actuated adjustable hub which changes the relative rotation of the driven pulley and the cam

Jimmy57 posted a better picture of this but this one shows how the reset valve shunts oil to one of the two ports to the VVT , this differential pressure chsnges the B1 to A1 rotation which changes the valve timing.

The reset valve has to work hard, I once calculated it has to adjust 200 times per second at cruise rpm to adjust on each stroke. They can test ok for ohms but still be tired , and dirty oil or plugged up junk will compromise operation

[scot850]

Both cars have had multiple oil changes since the solenoid valve was swapped with cleaned used ones. Oil changes are with synthetic oil and done every 10kkm or less (a bit over 6k miles).

Now that does not mean they are not affected by what previous owners did or did not do in terms of oil changes. I'd run seafoam through the engines prior to an oil change, but have to say I am always worried that the cleaning could be worse for the engine than leaving alone!

I'll look into the Vida checks

Thanks everyone!

Neil.

[vtl]

The reset valve has to work hard, I once calculated it has to adjust 200 times per second at cruise rpm to adjust on each stroke. They can test ok for ohms but still be tired , and dirty oil or plugged up junk will compromise operation

Oil pressure will not change 200 times per second, it is too fast for pressure wave propagation for such a viscous fluid. And it perhaps would make the wave supersonic, which is very destructive VVT solenoid is driven by PWM (pulse-width modulation) to imitate analog driving force where the only available input is digital. It relies a lot on oil viscosity and VVT hub responsiveness. And solenoid responsiveness, of course.

[scot850]

Again, great info one and all! Thank you.

I guess though I will just have to do the old school method of making sure the timing belt was fitted correctly on the 02 (I think I will find it is one tooth out) and on the 06 swap the cvvt solenoid again and see if the issue goes away. The belt on that car I think was fitted by Volvo but it does not mean it is right, so again check the timing first.

Appreciate all the inputs!

Neil.

[vtl]

You have VIDA, right? At least for 06 you can monitor camshaft adaptation angles, that will tell you if the sprockets were reinstalled correctly. For 02 I don't remember. VIDA can also run VVT test and tell directly if VVT system passed the test or not.