Hello and thanks in advance for any help! Recently took on a project to learn a thing or two and replaced the engine in a 2001 Honda CRV. The engine was a JDM and an older version of the B series, it did not have a crank sensor (CKF) so I bypassed it at the ECM using this technique: https://ff-squad.com/wp/?p=309 Instead of a clip I used a jumper wire and soldered everything together for better continuity.
Managed to get everything back together and it started right up, but could tell right off the bat that there was an issue, it was running real rough at first and shaking the car a bit and idle was fluctuating a bit, when I revved the engine up a bit (over 1000) it smoothed out some. I did the timing and took it for a spin. It seems that it has random but constant misfires at the lower RPMs (around 2000 and below) and especially when under a load like accelerating. Can hear it popping as I drive. It also has very diminished power, super slow to accelerate and barely makes it up my driveway which is a fairly steep hill. It continues to be a bit of a rough idle (shakes the car a bit), but holds at about 750 after it is up to temp which is on par with what the manual says is correct. I have taken the valve cover off about 4 times now checking and rechecking the timing, all marks are right on point and confirmed that TDC for Cylinder 1 was right on with the marks. I've gone through and put each piston at TDC for he ignition stroke and adjusted the valves per manual (.004 for intake and .007 for exhaust) For this I ended walking off the valve screw nearly two turns for every adjuster screw consistently. I've adjusted the throttle cable. Checked for vacuum leaks by pulling the intake hose off the throttle body and blocking the upper port with a finger and the engine began to slow and stall. I've tried two PCV valves, both I have no reason to believe there is anything wrong. I've done the ignition timing a couple times and it is lined up perfectly with the red mark. Using the ignition light I have confirmed that there is a current going through all 4 wires to the plugs and the wires and plugs are all new. When I pulled the plugs after about 6 miles of driving down the road, cylinders 2 and 3 seemed fairly normal maybe a little more carbon than there should have been after only 6 miles, but cylinders 1 and 4 were completely coated in black carbon. The fuel injectors were working for the previous engine, but that could be a culprit if the plugs are getting extra rich fuel in only half of the cylinders (1 and 4 are in sync with the same TDC). Everything seems to point towards a timing issue, but it just seems like I have confirmed it can't be that, by checking ignition timing, all marks are dead on, even after driving about 6 miles on both cams and crank, I've checked clearance on valves at TDC for ignition stroke on all for cylinders and they are all closed at TDC. Looking for suggestions on what I might try next. Check engine light has remained off this whole time except when I unplugged the IAC valve to check the idle it came on immediately with an IAC code that didn't come back when it was plugged back in and codes were cleared.

 

As a follow-up, I noticed that while the engine is running I can pull the wires on both cylinder 1 and 4 and there is no change. When I pull for 2 or 3 the engine dies. I've tried swapping the fuel injectors 1-2 and 3-4 and there was no difference. I've also no checked compression and it looks like all cylinders are around 175psi which is in spec per the manual, I was surprised to see the compression for cylinders 1 and 4 were actually reading a few PSI higher than cylinders 2 and 3.

 

Sounds like you got a bad replacement engine???

 

Wet plugs means they aren't firing. Sooty black is a too-rich mixture. Points to injectors?

 

have you checked timing and distributor cap wire placement.

 

Pulling the spark plug wires on misfiring cylinder 1 and 4 and having no change in power or running of engine
It should mean there is little to no contribution from cylinders 1 and 4
Could be due to the wires, plugs, and/or the fuel injectors.??