No start after dying on wife on way home - multiple tests already run with no answers

[ggleavitt]

I took a poke at your codes in VIDA and tried to provide my best guesses (pretty much follows what Roger has already suggested):

643A – camshaft position, intake = too high or too low (> +/- 8 degrees from TDC)
644A – camshaft position, exhaust = too high too low (> +/- 8 degrees fromTDC)
3000 – camshaft position sensor, intake = signal too high or signal too low (out of range)
3010 – camshaft position sensor, exhaust = signal too high or signal too low (out of range)
130A - intake air leakage- MAF intake path, check to see if this is historical ?
982A - ECM- check to see if this is historical ?
919A - ECM faulty signal- check to see if this is historical ?

The VVT hubs will indeed move at will when no belt is on. Some hubs are spring loaded I believe, the hubs on the XC90 are not.
VVT in/out play- over time the hubs get a little worn out (internal O-rings I suppose). I would like to think it's more an exhaust problem than intake due to the heat (at least it was on my car), and the result is usually an oil leak from the front cam seal. At any rate, the in/out play you're seeing on the hub is probably not a contributor to a no-start condition.

Codes were read with DICE and VIDA? And these are all the codes? I'm guessing an out of timing condition with enough working right that you're not banging your valves against the piston tops (least I hope you're not). That both intake and exhaust are noting they're out of alignment perhaps suggests the issue is between the crank and the cams but that's just a simple guess based on your codes.

Maybe something else to troubleshoot but that might be better determined once you get the timing alignment back to correct.

Good luck !

[Roger_850T]

Yeah, I'll have to get a new gear. I think it will take some serious pounding to get THAT one back on. I don't see how it could have moved either way. And it did not loosen up as it came off. It was a pain and took full pulling pressure all the way to the end release!

It may be that it was difficult because the gear was rotated, and you were pulling it off against misaligned splines. (Meaning that the new one may just slide on nicely once you have it correctly lined up.

Interestingly, the intake blue forward pulley has some play in it. This means with the belt off, I can rotate it back (counterclockwise) a full 4 teeth before I feel resistance and the cam actually moves. When it rotates back, it also moves about 1/4 inch away from the block towards the wheel! I don't know if that is part of the VVT, but maybe we're on to something here?

I feel about that much play in the VVT hubs. The VVT moves pretty freely when the engine is off. When it's running the moving belt will pull it to the "full forward" (or most retarded) position, then oil pressure in the VVT solenoid will rotate the internals to move it "back" (or advanced).

While you have it off, take a good look at the marks on the gears. Specifically on the crank gear, if you didn't already notice it, there are actually two marks that straddle the mark on the block (oil pump). While you have the gear off is a good time to mark the new gear in a more visible location.

Also, since you know it's somewhat out of alignment (due to the low compression), if you don't already have the cam alignment tool, it might be worthwhile to get one. For just a timing belt change, you can get by with making marks and setting it back on the marks, but since you know it's been incorrect, it might be worthwhile to do it "by the book" and meticulously set it up.

Roger

[scottinalaska]

Here is what I am talking about with the camshaft sprocket movement without the cam moving at all. A VIDEO link:


https://drive.google.com/open?id=1gU3aF ... Mq1Ync2LR0

[Roger_850T]

That camshaft sprocket movement looks to me like what I would expect with the VVT cams.

I would re-assemble, following the manual very carefully to get the cams timed correctly, and turning over by hand very carefully to make sure you don't have any interference, and check the compression. Hopefully, with a new crank gear, it will be good.

Good luck!

Roger

[scottinalaska]

As it turns out, that cam movement (for both of them!) is normal.
After putting the new Crankshaft gear back on and timing it correctly, I discovered that indeed, it was a solid 2 teeth off because of the internal splines on the gear being laid over. Glad Volvo thought enough to make the crankshaft steel harder than the splines on the gear! I did take a triangle file to clean the crank splines though! The new sprocket then slipped right on.
I positioned it perfectly on the timing mark and put on the pulley together with the nut and four bolts. I then marked with white paint where the pulley was in relation to the block so I had an easy verification of proper lower position from the wheel well. I had to put oil in each cylinder for it to develop compression since they were washed down from gas not igniting too many times in the last month. Then it started right up! Runs like a top. I had compression of over 160 in every hole.
The catalytic did throw a code for not being as efficient anymore. Maybe this was due to it running so retarded for the past month or more. So THERE is the answer! All related to a nut either not being reinstalled or not tightened 20K miles ago by the dealer during a timing belt change.
Thank you to all who chimed in with your thoughts. Great help!
Scott, in Alaska