Losing power for a month, now no start. lots of codes

scottinalaska · Post by **scottinalaska** » 19 Oct 2017, 13:43

The wife has told me the 2004 XC90 2.4T hasn't felt as powerful recently. She was right. Unfortunately, she got stranded this week! After driving slower and slower for 4 miles (losing power no matter where the throttle pedal was), it finally died. It will turn over fine, but will not start. I got lots of codes and since "camshaft sensor) seemed pretty common thread in the codes I pulled, I figured I should verify the timing. When I pulled the inner fender cover to inspect the crank pulley, I discovered the nut was missing. Thus, I could not even rotate the engine to verify marks. The belt was snug and not worn. It had all been changed by the dealer at 120K. Now it has 150K.
Don't know how that would affect anything. The serpentine belt still spins and the TB is still on.

Here are the codes I pulled:
643A – camshaft position
644A – camshaft position, exhaust
3000 – camshaft position sensor
3010 – camshaft position sensor
130A - intake air leakage
982A - ECM
919A – ECM faulty signal

Any direction with this combo?
Thanks!
scott

Post by **ggleavitt** » 20 Oct 2017, 08:50

Might be wrong but based on the first 4 codes, it appears something "hopped" the timing belt, since both intake and exhaust are affected, I might suggest it's the crankshaft that's out of alignment compared to the camshafts but that's just a guess.

Were it me, I might take the whole thing off and re-install once you get a nut (PN 3531111) back on the crank pulley damper, suppose to also be one small bolt to hold the damper against the pulley (PN 985374) I think.

Did you have any check engine lights before it died or only afterwards?

scottinalaska · Post by **scottinalaska** » 20 Oct 2017, 18:12

Only afterwards did the codes pop up.

Masscomguru · Post by **Masscomguru** » 20 Oct 2017, 20:01

Just went through something similar with the wife's s60 t5. The variable timing control solenoid failed effectively putting far enough out of timing to not stay running at idle. Dealer thought it skipped a tooth but the vida test showed a close failure on the valve.

Post by **mrbrian200** » 20 Oct 2017, 22:07

Did you say the nut was missing from the crankshaft pulley? The large one in the center?!

I'm 99.9% certain if that nut is missing/not torqued down properly the splines between the TB gear and the crankshaft can shear/strip off over time. The pulley attached to it isn't simply a pulley--it's a harmonic balancer. That center bolt absolutely must be present and torqued properly to hold the whole assembly locked to the crankshaft to prevent hammering which would eventually shear off either the splines mentioned or the stress fracture the crankshaft itself.
This is just an educated guess, but I'm thinking a tech at the dealer either didn't get it torqued down properly or (eek!) forgot it after replacing the TB. You need to get that dealer involved. These aren't known to work themselves loose when torqued properly. Volvo service procedures call for this to come off when changing the TB. Somebody messed up or was careless.

Referencing another thread "Do You Really Use Torque Wrench?"
viewtopic.php?f=9&t=83028
Accessory pulley/harmonic balancer bolt or nut to the crankshaft end is one of those ones I would absolutely never ever 'guess'. Torque wrench for this one (and a new bolt or nut if OE calls for it) every single time. No exceptions.

scottinalaska · Post by **scottinalaska** » 21 Oct 2017, 10:54

I sure did say the nut was missing! And it has run fine for the last 2 years. When I went to confirm the timing marks was when I discovered it gone! Normally, I do my own TB and other things. But I was out of state for a year and told the wife to take it to the dealer since it was due and we PAID to have it done "right." Apparently one of those last steps was left out whether it was lack of loctite or proper torque or maybe lack of nut! So here I am about to pull the plugs so I can at least turn the crank by hand without a nut to verify timing marks. Thank you for your input guys. Good stuff.

Post by **oragex** » 21 Oct 2017, 12:45

Looks similar to this thread as well
viewtopic.php?f=9&t=58219&start=10

Post by **Roger_850T** » 22 Oct 2017, 19:24

I just went through the "loose crankshaft pulley" on a V70, and this is sounding familiar. 2 years is a long time, but who knows? Anyway, I would pull off the accessory belt, and the timing belt, and then the crank nut and check that the splines on the inside of the gear were ok. Mine were bad - I ended up replacing the gear to fix the problem. At this point, I think you'll find them worn down to nothing, and a bunch of play in the gear. If yes, I would fix that first - that might be the root cause of everything else, especially the cam sensor codes.

Roger

scottinalaska · Post by **scottinalaska** » 14 Nov 2017, 18:10

Update time. I finally got a crankshaft nut from Volvo and have dived back in. First things first: Check those timing marks! Well, the front cam lines up nicely and the back cam ain't near it at all! Is this a problem? I don't EVEN want to continue if we have blasted the valves because something really went wonky! This is what I found. I have not shifted the belt at all. The belt has nice tension. Nothing looks out of place (Except the cams!). The entire job was done AT VOLVO dealership 30K ago.

Post by **mrbrian200** » 15 Nov 2017, 00:03

Please explain exactly what you performed.
Did you inspect or replace this guy?

Capture.JPG

Regardless whether or not the gear on the crank needs to be replaced, if you didn't remove or loosen the timing belt the intake and exhaust pulleys should still line up with their respective marks independently of where the crank is. This points to a failure in the belt chain (tensioner, pulley, water pump, or stretched belt).