2003 Honda Accord Tourer 2.4 auto (CM2)
Day -3: Driving normally
Day -2: Possibly feeling a little rough sometimes but hard to put my finger on it.
Day -1: As day -2 but a little more. Perhaps.
Day 0: Starts but won't run unless throttle used to keep revs above maybe 2500.

Car was taken to our local garage who couldn't really help as they didn't have the gear to read the Honda DTC codes. Car was then shipped to nearest Honda main dealer, some 50 km away.

The Honda dealer said that the car was showing DTC P0341. We were told this meant that the cam chain was out by at least 6 teeth and this had happened because the oil wasn't changed often enough (it was) and so the cam chain had worn. We were also told that the repair cost was a minimum of over 3000€ and if (as was apparently likely), valves had impacted pistons, the cost would be much higher. We didn't have that kind of money available, not to mention that it ws probably more than the car was worth, so we had it transported back home.

The vehicle arrived with a compression test result which indicated that all was good. AFAIK, this is a pretty conclusive indication that we don't have bent valves.

18 months later, I finally found out that that code can cover a multitude of issues and so finally set about diagnosing the problem, following the Honda document "DTC P0341: CMP Sensor A and CKP Sensor Incorrect Phase Detected".

So far, I've checked the VTC strainer on the front of the head (not clogged at all), and the VTC solenoid control valve on the side of the head, which checks out fine.

Time to bite the bullet and start the serious stuff! Cam cover off and looking for the marks on the cam sprockets as per the Honda document. Either they don't match or they're 45 degrees out from each other! So here are the best photos I managed to get of the sprockets. For reference, I've included the relevant diagram from the Honda diagnostic document.

Any ideas?


Inlet cam sprocket (VTC actuator)



Both sprockets


Honda's diagnostic diagram



Exhaust cam sprocket, as much as I could get.

 

A couple of months later...

Looking through what I posted, the penny dropped. The problem is a common one: the timing chain had stretched to the point where the tensioner couldn't keep sufficient tension on it (and possibly the tensioner is also on its last legs). And so, the chain had jumped and the valve timings were out.

It took me a while to get started on the fix and then to order the required tools (especially the one for holding the crankshaft pulley still whilst undoing its bolt).

So the job is to change the timing chain. Best practice is to change the sprockets, guides and tensioner at the same time, ditto the oil pump/balancer shaft chain etc., so I ordered the complete kit and got started.

It turns out that, AFAICS, this is the longest of the K series engines and the clearance between the chain case and the flitch plate is tiny. For several of the 6mm bolts that need to be removed, there's simply not enough room to get a socket on them, so some kind of offset spanner is required. I also found a pipe spanner useful for one or two of them.

So, I now have all of the bolts out and the chain case still won't part company with the engine. I'm vacillating between "I've missed a bolt somewhere" and "It's the liquid sealant Honda use acting like a strong glue". I have got a finger on to each one of the 12 bolt holes and verified that it is, indeed, empty! And yet I can't shift the casing. I'm loathe to put massive force on it because I don't want to risk breaking it. Does anyone have any ideas what might be going on?

Footnote
In case this is of any use to others, this is how I undid the crankshaft pulley bolt:
The usual big steel tool that fits in the huge hexagonal "socket" in the middle of the pulley, plus a longish ratchet handle designed to be hammered, the end resting on the suspension to prevent it turning. The bolt itself was inside a 17mm impact-type socket (6 faces, not 12), on the end of a 60 cm bar. I couldn't shift it. I attached the wire rope of a ratchet pulling device to the end of the handle and the other end was attached to a tree. Slowly tightening the ratchet, eventually there was a CRACK! and the bolt turned maybe 60 degrees. At that point, I had to loosen the wire rope and reposition the bar. Then there was more puling and this time the bolt turned smoothly, to the point where I could finish loosening it with the bar.

The pulling device I was using has a capacity of 2 tonnes and judging by how much I had to work at this, I'm guessing that about half of that was being used. I don't want to think what the actual torque was.

 

And again... a few weeks later.
I finally realised two things:
1. When counting the empty holes, I'd managed to count one of them twice (once from above, the other from below), and therefore there were only 11. There was another bolt hiding somewhere.
2. I casually glanced at a photo of the *back* of the chain case and realised there was an extra (to me) hole near the location of the VTC control valve.

So, I looked hard and eventually, not seeing anything, took a photo of the empty VTC valve indentation with my phone. And, lo, half way down that indentation, right at the to of it, where you haven't a hope in hell of seeing it... was bolt number 12. It came out very easily and the chain case parted company with the crankcase/head easily.
Not that it'd come out of the engine bay - there's a water hose from a spigot on the water pump to the oil filter housing on the back of the engine. This has to be removed and the hose folded back out of the way. *Then*, out came the chain case, at last!

The old guides etc and the chain came off easily enough. Inspection conformed that changing the crankshaft double sprocket, oil pump chain etc. was not on without dropping the sump. It also looked as though those parts were in good enough condition that changing them wasn't essential.

And so, finally, re-assembly with the new parts started. But, to cut a long story short, there's a problem:
The coloured links on the new cam chain won't align with the timing marks on the camshaft sprockets. Not both cams at the same time, anyway! If I turn one of the cams to force alignment, it's against considerable resistance from valve springs and, unless I keep tight tension on the chain, it will leap off the exhaust sprocket (because that's the one I "forced", back to the position shown in the photo.

I'll go look again in the morning because the photos aren't clear enough :{

The only thing I can think of is that it's the wrong chain. Anybody got any other ideas?

BTW: I'm posting the details because they may be useful to someone else doing this job for the first time. To which end: It's now clear that it would have been far quicker and easier to get the engine out of the car to do this job. This is not the case, AFAICS, for most Accords but it is with this one! Alternatively, having a pit would have helped :/



The timing marks on the VTC actuator aren't very clear here but they're there if you look hard And they are pointing to the right place on the chain.

 

So the problem aligning the sprockets was due to me misreading the instruction about "turning the VTC actuator until it locks". I'd been trying to turn it the wrong way Yes, I felt suitably stupid. Turning it the other way, it moved quite a bit and then it was possible to install the new chain with all the valve timing correct. It was still a bit of a forced operation but once I got the tensioner in and unlocked, the chain stayed had put after several crankshaft rotations, so I was happy. After getting some advice from a techie at a very helpful Honda Main Dealer in West London, I proceeded. He said that the actuators do sometimes lock up in odd configurations but once there was oil pressure in the system, it normally straightens itself out. (Long story short - seems that it did )

Getting the chaincase back on again was easy enough: some liquid gasket (not the sticky goo that Honda use) applied to the case itself made that part fairly easy. Getting most of the bolts back in was also not a problem. The last ones were... difficult. At the end, I used the following tools:
10mm socket and very small 1/4 drive ratchet handle
Half-size torque wrench, 1/4 drive.
10mm ring spanner.
10mm crows-foot spanner with 1/4 - 3/8 adapter.
10mm ratchet spanner with hinged head.
10mm ratchet spanner without hinged head.
10mm pipe spanner

In some cases, it ws one tool to start with, then switching to another for the almost-final tightening, then the torque wrench. After that, pretty much everything was plain sailing, although a minor dose of COVID and some weeks of bad weather got in the way.
As I had the lid off anyway, I adjusted the tappets (crows-foot spanner perfect for this job, together with the short torque wrench and a short 1/4 extension rod).
New accessory belt and tensioner pulley.
Finally, battery charged and turn the engine over (no spark plugs and PGM-FI relay II pulled), until the oil pressure warning light went out. That took at least 30 seconds and had me on tenterhooks
Plugs in, coils etc in, relay replaced and the moment of truth arrived...

It started instantly and ran fine. I jumped and then swore as I really didn't expect that!
A few issues with not idling well got better as it warmed up; a few more starts and the problem disappeared. Almost certainly a vacuum or solenoid valve partially stuck loosening up (after not being activated for over 18 months).

Monday, it goes for it's Controle Technique, the French check done every two years after a car is 4 years old. I'm happy to pay just 70€ for a thorough check by another set of (skilled) eyes. After the car hasn't been used for so long, all sorts of things might have decayed and I'd rather know about anything serious before it bites us.

A reasonably happy ending.

BTW, if anyone wants elaboration of how some part of this job went, just ask.