Just picked up a new DD last night (99 EX Coupe, 5-spd, 210K) and have some gremlins to hunt down.



Check engine light is on and sometimes flashes while driving. Had the codes pulled: P0301, P0302, P0304, and P0300. Misfires on cylinders 1, 2, and 4, and general misfire code. It idles a bit rough, sometimes as low as 500rpm, and the misfire can be clearly heard from the muffler. However, when driving it seems to run just fine. Pulls strong, no noticeable misfire, everything works fine. Distributor, cap, rotor, wires are all new, installed by the previous owner, not sure about plugs. Not sure the age of the fuel filter either.

I plan on troubleshooting this weekend but just wanted to see if the symptoms are typical of a single problem.

 

Check/replace plugs, clear faults and reset ecm.
If that doesn't fix the issue you will need to do a compression and pressure test.
Good luck!

 

Cylinder 2 is dead. Verified I have spark, plugs are the correct NGK ones and look brand new.

Resistance on the injectors is correct, 12.6 across the board. What should I be looking at for voltage at the plug? 5V?

Will be compression testing tomorrow and, depending on the results, a leak down test. Should have the problem identified by tomorrow. If compression related, I'm really hoping it just needs a valve adjustment. Right now that's the best result I can hope for.

 

When you say cyl#2 is dead, you mean no output difference if you unplug the coil wire?

 

Correct. Each of the others when pulled damn near stall the motor. No change pulling the plug wire from cylinder 2. Gotta get that diagnosed/fixed before worrying about the misfires.

 

OP, check the spark plugs. If anything, swap cylinder 2s plug with one from a different cylinder, and see if the symptoms change to the other cylinder.

 

I'll give it a shot, but all plugs look damn near new. Plugs are in order in the picture, you can see the one for Cylinder 2 is a little discolored.



Messed around with it a little more this evening. Have power to the injector plug so I don't think that's it. If the compression test comes back fine across the board, I don't know where the **** to look next.

 

Welcome man. Don't see you much in this forum.

What brand plug wires?

Did you inspect the inside of the distributor cap and the rotor?

 

Now that I'm back in a vehicle that requires some work here and there you'll be seeing more of me. I just got tired of seeing the same questions with the same answers day in and day out in the tech forums, so I stayed away.

Import Direct. Which a quick Google search tells me comes from O'Reilly Auto Parts.

I haven't yet. Thing is, it's all (the entire distributor) brand new so I doubt the ignition components are the problem. It's not Honda OEM brand new so there is a possibility, but I would hope not. I plan to do some more digging before running off to rent a compression tester. I already verified spark, Cylinder 2 is just as strong as the others from what I can tell visually.

The plug in the pic above is a little "whiter" than the others, but the white color is normal, correct?

 

Check compression and if okay, swap the injectors around and see what happens.

 

I personally would start by installing Honda plug wire and inspecting the inside of the aftermarket distributor.

 

Swapped around plugs and injectors. Cylinder 2 is still the problem child. Heading for a compression test shortly.

 

 

Okay, so learn me D-series real quick, was always an F/H/B guy.

Looking for another longblock in case this turns out to be rings. Should I look for another Y8? Is there a "better" option that I can still move all my sensors, accessories, etc to without having to hunt down extra parts? OR is there a "better" shortblock that will accept the Y8 head with no modifications or hunting down extra mounts/parts? I just want to be able to pull my longblock, drop the new one in, bolt everything up and go.
Thanks in advance

 

I'd lean more towards burnt valve than rings. I say pull the head and inspect before jumping to bottom end swaps.

 

This sucks 😢
Now perform a cylinder leakage test and see where the problem is. I would also guess a valve issue so before you go hunting for a block, figure it out.

 

It does suck, but even with the work needed I'll be into it for less than others in worse physical shape that I found.

I have a leak down tester but my compressor **** the bed. Gonna do the valve adjustment then head over to someone with a compressor to really find out what's going on.

And looking around I don't think another swap is the best option for me. Have a good acquaintance with a a shop of his own, gonna see what he'll charge for the work if I take the longblock to him, should save me a ton in labor.

 

Valves were loose across the board, more so on Cylinder 2. Runs a lot smoother after the adjustment but still having problems with #2. Waiting on a compressor to show up and will get the leakage test done to tell me where my problem is.

 

Alright, not rings thankfully. Looks like the exhaust valve are to blame. Getting a quote for the head work tomorrow, might just pick a fresh head up though depending on what I find.

 

Trading a set of wheels for a fresh D16 head and gaskets. Guy never put it to use after paying for all the work

 

Yes, when i worked at O'Reilly they sold that stuff.

**** O'reilly, those two-faced bitches.

 

Aware of any common issues with their ignition components? I couldn't find any markings on the distributor specifying brand, but consider the plug wires I'm assuming the dizzy came from them as well. Just curious if I should start hunting for an OEM dizzy to keep for if/when this one fails.