MadCityS2K

MY 2000, 127K total miles. Engine seems to run too rich. Black sooty film accumulates on rear of car and puffs smoke on acceleration. Back story: Engine was replaced ~10K miles ago (reason is a different story). Replacement engine — could find only 1 in the US with left side drive — had 45K miles with apparent ill treatment. Replacement needed new oil pan seal, water pump, etc. Warranted for 1 yr for internal engine issues — which did not appear, other than the black smoke. The engine is 1 mod newer than replaced engine. My guess is there was some electronic timing adjustment between the mods which leads me to believe a timing adjustment may be necessary. Honda service has no solution within their service options. Am considering engine overhaul, but not sure what we are going after at this point. Any suggestions?

Car Analogy

An engine overall will not address black smoke, which means its running rich. You'd spend a lot of money, and most likely reduce engine life, not extend it. These engines are notoriously difficult to rebuild. Most shops experience will work against them here.

The reason the engine is smoking is external, not internal. Don't throw rogue fixes at it in desperation.

If I understood, new engine is from a different year car? What year car, what year motor?

Which parts off old motor did you reuse? Ecu? Throttle body? Etc?

s2000Junky

Agree with post above. Most likely an external component, not the engine itself, unless there is a substantial amount of oil burn/usage like 1Q ever 500 miles give or take for reference and its creating some fouling. If oil usage is within general common 1 Quart per 1000-3000 miles your good. Good enough. Look elsewhere.

You running a cat delete?
Any cel?
upstream 02 sensor may be getting tired.
TPS may be off calibration
map sensor

maint items, such as spark plug condition, coil packs, air filter.

Just a couple things off the top of my head.

MadCityS2K

Very good perspectives. External? This is interesting. Plus overall good advice. Thank you.

Replacement engine is MY2000 like the chassis. I cannot lay my hands on the purchase detail, but I do recall that the engine was a rev level higher than the replaced engine. I have always considered there could have been a software rev with whatever was rev'd in the engine. Honda did all the work -- bless their souls as it was a challenge. Almost everything external on the "new" engine was replaced with better condition equipment from the old engine including coils and water pump. Not sure which fuel intake systems were used.

Oil usage is up (or down) to ~500 miles/qt which is about double what I experienced with the old engine.

FYI, the old engine failed with a very difficult to detect occasional misfire. Many hours of testing revealed a slight oval shape in the #3 piston wall at the bottom of the stroke. Honda had apparently not seen it before.

I will have Honda check the items you list.
(I am not savy enough to decipher your script)

Again, thank you!

s2000Junky

Given your updated info, im re considering something external as the issue. Burning 1 quart oil every 500 miles is severe and would generally cause premature fouling of spark plugs and 02 sensors creating the symptoms you are describing. Its sounds like a repeat of what was going on with your last engine. It is not uncommon for cylinders to become ovalized on these high revving motors over time/mileage. But its also not something that randomly happens, its generally after a lot of miles and or regular track abuse or if the engine was boosted. By your OP description is sounds like they swapped in a abused engine. I would have a leak down and compression test done and confirm. Those test results and given your oil usage amount I hope you have some warranty recourse. A maximum of 1Q per 1000 miles was the given tolerance from Honda on oil consumption with this engine, but that is severe and not a tight healthy engine, you are double that.