02 XC70 - throttle falter/drop when returning to idle

[scot850]

Sorry, missed your response jonesg!

Thanks for clarifying the differences in the cam code fault is not the CVVT solenoid. I will take a look closer at that.

I will take your advice and smoke the intake system. I am working on the big ticket stuff (cost wise) first.

Neil.

[jonesg]

Sorry, missed your response jonesg!

Thanks for clarifying the differences in the cam code fault is not the CVVT solenoid. I will take a look closer at that.

I will take your advice and smoke the intake system. I am working on the big ticket stuff (cost wise) first.

Neil.

to access the exh cam sensor you need to remove the cross brace and its bushing mount from the block, the mount covers the sensor.
its easier to just smoke the system.

[scot850]

Thanks for that. I just looked at this and realized in true Volvo fashion why make a job easy when you can make someone take half a car apart to do a simple job! Crankshaft sensor on the other hand is much easier as long as the nut comes off!

I might have to go to the junkyard for a cam sensor as the work involved to disassemble twice is not worth is, but likely I have to do the job twice because of pulling one at the junkyard. I need to check which is the right one. There are 6 variants on P2's, but I think half are for NA's.

Really appreciate the help!

Neil.

[scot850]

What a phaff getting that brace off! Life needs to be easier.

After removing the 9 million bolts to access a service part, I got the cam position sensor out. There is a little oil residue in there but looks like it may be just that. The seal looks recent. Possibly the mechanic just did a crap clean up? Anyway, I have done that.

Question: Should the cam sensor have an oil seal 'O'-ring on the shaft where it fits in the housing? I can't see one listed on the Volvo sites, but I do see it on aftermarket parts. In some way that does not make sense as the part hangs downward, and also there is no seal on the plastic cover, although it also looks like one could be fitted. Looks like a distributor cover in how it seats.

I now have to test the part and see if it is dead or dying. Not dead I believe but possibly not 100%. Will need to do a junkyard run for one and a couple of other parts that are missing in that area.

Neil.

[scot850]

Removed the TB today. I did notice when I tried it before removing by putting the key to Pos II, the TB was really noisy, like a coffee grinder. Then again when sitting for a short time and finally when switching off. I have read they have plastic gears that strip out. Really don't wand to get into taking it apart. I connected the 'new' one. Not sure it is working correctly. On my P80 when you switch the ignition on, the throttle flap moves back and forward like it is finding the ambient position for starting, and then I don't hear it after that.

The 'new' one does not seem to move on switching the ignition on that I can see. However, when switching off it opens fairly wide and then closes again. The difference is it is totally quiet! It is difficult to see from the driver's seat, so tomorrow I will press gang our son tomorrow for key operation, and I will swap the 2 TB's over and watch their operation more closely. I know the 'new' one will need to at least be reset so maybe that is why it is operating the way it does. It would be good to have had the one from the 05 V70 2.5T as it should be close or the same as the XC70. I'm not sure what the one came from my buddy loaned me for testing.

Still trying to figure out the cam sensor issue. jonesg has been awesome and patient (so far!). His help and guidance it really appreciated for my fast learning curve.

More stuff disassembled, and no major further forward. I will have to try and get the TB's figured out and the operation of the cam sensor from a testing perspective.

Neil.