P0420 After VVT seals replacement

[nliutilitt]

2004 V70 2.5t, 183k miles

So I replaced the VVT seals per instructions I found here. They were excellent and I didn't have any real issues at all, lined up the camshaft marks on the rear side, VVT marks on the timing side at full clockwise travel, and the mark on the crank, everything buttoned up and started right up. no rough idles, no codes, no power loss, no wobble in the tensioner, no extra parts, no loose hoses or connectors far as I can tell, everything seemed good.

Then couple hundred miles later P0420 popped up. Cleared it, couple hundred miles later again P0420. This is after resetting everything by disconnecting the battery.

No other codes. No gas smell in exhaust. gas mileage is same as before, maybe a hair better.

Looking at basic live data most things seem in order
Closed Loop
~680 Idle rpm
~88C Coolant temp
3.25g/s MAF at idle, ~24g/s when cruising at 70mph. about normal from past observations
3~5% LTFT, about usual for winter time based on past observations
-5 to 0 Timing Advance. Not sure if this is within parameters. Cold start it's around +10, then settles down as temp rise.
B1S2 changes between a bit, sometimes near 0v while cruising on interstate, sometimes ~0.8+. Normal I think.
Equivalence Ratio is constant near 1. Looks normal

Looked at some things in VIDA while parked

vida.jpg (100.24 KiB) Viewed 383 times

What am I looking at here? Seems like some conflicting data... Exhaust sensors indicate rich condition I think? But LTFT and Equivalence Ratio doesn't?

does it all point to bad O2 sensors? AFAIK they have never been replaced...But I only have service records since ~50k.
Cat going bad? I've gotten P0420 in the past, but not this frequently.

or is this something more serious and complicated?

[vtl]

Since you own DiCE/VIDA, you can read VVT adaptation angles after revving the engine above 1500 RPMs (self-test happens there).

Bosch oxygen sensors in this car have lifetime of 150k km (km, not miles). If you haven't replaced them yet, they are long overdue.

[nliutilitt]

Untitled-1.jpg (209.28 KiB) Viewed 347 times

Adaptation angles -3 for Intake; 6.2 Exhaust. In normal ranges I think.

So I guess it's down to O2 sensors then, seeing as they are long overdue.

[vtl]

Under +/- 4 degrees is OK, under +/- 8 is tolerable, though with power loss. 8 or more is a chance for piston to smash into valves.

Myself tries to get it under 1 degree. Does not take too long if you know what you're doing.

[nliutilitt]

loosen the adjustment bolts and rotate the hub right? but which direction? 6.2 adaptation on Exhaust means I should rotate it 6.2 clockwise? and counterclockwise on Intake?

or the other way around, 6 degrees CCW on exhaust, and 2.6 degree CW on Intake? I guess a torque wrench can be used to meansure the angle?

[cn90]

I think your best bet is to set it up again:
- Lock the Rear canshafts as you did during cam seals job.
- For the VVT sprockets, make sure they line up correctly.

As long as you have the rear camshafts locked in position and the VVT sprockets lined up properly, you should be fine.
This assumes that you did not disturb the 8-mm bolts on the VVT Hubs.

[vtl]

loosen the adjustment bolts and rotate the hub right? but which direction? 6.2 adaptation on Exhaust means I should rotate it 6.2 clockwise? and counterclockwise on Intake?

or the other way around, 6 degrees CCW on exhaust, and 2.6 degree CW on Intake? I guess a torque wrench can be used to meansure the angle?

Start with the intake, since you have some degree of freedom over there. Loosen the 3 M10 sprocket bolts, rotate the camshaft by the center cap any direction you want, but just a tiny-tiny bit. Fix the bolts, start the engine, rev above 1500, read adaptation angle. Decide where you have to go next.

You may need to redo the work fully if you ran out of oval slots in the sprocket.

I would think a positive adaptation means the computer had to ADD this angle, so the real position is negative to that. It adjusts CCW, so you have to go CW. But I had a few beers and Margaritas, so play safe and stick with plan A (adjust the intake a bit and see where you really had to go).

If you get under 4 degrees - call it a day.

[dikidera]

That O2S sensor is reading mighty suspiciously.

[nliutilitt]

Ok, made the VVT adjustments, pretty straight forward. Just had to disconnect battery to reset adaptation before checking it after each adjustment. Got both intake and exhaust adaptation angle to less than 1 degree. Idle is noticeably smoother.

only very minute adjustments. 1mm travel on the hub circumference is about 1.5 degrees of adjustment.

1. Disconnect Battery
2. Loosen VVT Timing pulley bolts, 8mm.
3. Adjust VVT with T55 on the center plug. Positive Adaptation angle, adjust CCW. Negative angle, adjust CW.
4. Torque down Timing pully bolts, 10nm
5. Reconnect battery, verify adaptation angle is reset to 0.
6. Start engine and rev to 1500, adaptation angle should update

Just O2 sensors left to do.

Thanks again!

[cn90]

This is the kind of problem that I hate: an unrelated new problem!

There is a basic rule in car repair: whenever there is a new
problem after a particular repair, go back to the job you just
did and trace step by step to see if you did anything wrong.
Or did you accidentally disconnect some connector/hose etc. unrelated to the job?

Fair enough, so you may spend 5 min or 4-5h etc. going
over the job you just did.

Or the problem may be elsewhere...In this case, you just
wasted 4-5h going over the previous job, only to find out
there is an unrelated issue.

This is "the joy of owning a car"...