Hoping someone has had something similar to this before. Had an 06 Odyssey come into the shop needing a timing belt. We did a timing belt w/ component kit, water pump, serpentine belt, and serpentine belt tensioner. After putting the timing belt on we always start our motors before fully reassembling them to check that everything is good, all is nice and smooth. This time we left the bolt out of the end of the crank and the key for the crankshaft gear came flying out after a few seconds of running. Put everything back together (with the bolt this time) and let it run for a while. The check engine light came on for severe misfires on all 3 cylinders for bank 2. Removed the head and sent it to the machine shop we always use. They found 4 valves that needed replacement. Put everything back together and it all seemed okay (except that the power steering was whining for some reason, and we never opened the power steering system.) Turned the steering wheel a few times and the power steering got quiet. Test drove and all was well. Now the van is back with misfires on all six cylinders, running rich on bank 2, and the power steering is whining and foaming again. This thing is driving me nuts, ideas?

 

I feel for you on this one, as I'm not particularly thrilled with these keys being so loose that they fall right out, which seems to be the case on their other engines also. It would be nice if they were at least a slight tap fit into the crank. I'm sure at least a few folks changing belts over gravel had to go and get themselves a new key after removing the crank pulley.

I imagine your case is something different, since it did initially run well after assembly, although I saw a case where the supposedly non-bent valves passed a compression and fuel leak test, but still had a slight leak. Not enough for severe misfire in that case, but enough to cause a slightly rough idle until raising the rpm. The guy got lucky and the valve/s seemingly seated themselves in, but I would also imagine that it could have been only one valve with a mere .001" leak. Doesn't take much leakage at all for them to run terribly.

 

It sounds like it jumped time again.

Tough call. Do you spend $1000 now trying to fix that engine just to possibly have it come back again and again (possibly costing you a lot more) or do you just get a low mileage salvage engine and swap it in? Either way it's gonna be expensive. If the timing isn't off, I would pull the heads and if more than a couple valves are shot I would just get another engine.

 

I'm going to pull it back apart tomorrow and do a cylinder compression test and leakage test. Also going to inspect the plugs and valve lash. I just can't figure out why it's showing a perfectly steady vacuum gauge reading, and only missing at idle. The P0175 also throws me. I'm not terribly fond of Honda's engine management systems right now....

 

Check the fuel pressure for P0175. Fuel pressure should be 55-62psi. If it's too high replace the fuel pressure regulator, which is attached to the fuel pump assembly.

Any other codes?

 

did they replace the valve gides ?} many times i see when belts snap , we send the heads to machine shops and they usually TECHline advice us to do valve gides too

also the j35 with vcm has oil burning issues with the cylinder management system , specially coming from the 2 cyl. that the vcm cuts during vcm operation ,

honda has a sofware update on the vcm odysseys 06 and up i think where it actually shut off the vcm on iddle , email me the vin and i will do a vin inquiry bravocompany20@gmail.com

 

Check for PCM software updates, make sure the valves are adjusted correctly. If the software is up to date, and your are 100% sure the valves are not too tight, Watch the live data on your scan tool to determine which cylinder or cylinders are misfiring the most. A misfire on one cylinder can cause multiple misfires.
Replace the return line o-ring on the power steering pump, it's probably sucking air into the pump and aerating the fluid.