heres the story, picked up a 90 civic dx hatch for 400.00, great condition runs good, guy said it blows blue blown ring and fails emmisions

so heres what we did, drove it, runs great like a brand new car, but smokes a lot which goes away after some driving.

at first it blows blue then it goes away replaced by a ton of grey smoke, not white not blue and not black. so we looked it over and did a compression check, 200 thru all four cylinders. changed plug seals and valve seals, blue smoke gone. but it still smokes a ton., again which goes away when warmed up, but comes back when revved.

new parts its got is plugs, dist, parts we swapped out with other parts we had is intake, throttle body, o2 and cat.

heres the funny thing, when we remove the cat there is no smoke what so ever from the manifold, but plug the cat back in and theres tons of smoke. same goes for axle back, remove the axle back theres little smoke, plug it back in and theres smoke.

we have a 5 gas analizer and at first the a/r was lean at nearly 18:1 but still lots of smoke, then we had another ecu so we swapped that on, and now its rich at 10:1 to 12:1 hydrocarbons are in the 300s did not change from either ecu only went from being lean to being rich, the exhaust smells like halloween, smells like fireworks and fuel.

dont know whats up and or how to fix this thing.

 

I always thought blue smoke meant you have a blown head gasket?

 

okay, white/ gray smoke, if i remebr right is anitfreeze.
blue, is oil.
and black is fuel.

im not sure, im only 16, but it could be a little, blowby? maybe new piston rings, i know that on the power and intake strokes if they dont scrape of the oil on the sides it burns, giving you blue smoke, im not sure about running rich and lean though? i dont think losing compresion would do that. never worked on a honda motor in my life so im not so sure but i think maybe how it mixes the feul and air, maybe that is goofing up on you?


im probly wrong but i tried

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by roadracer321 &raquo;</TD></TR><TR><TD CLASS="quote">I always thought blue smoke meant you have a blown head gasket?</TD></TR></TABLE> you always thought wrong.. why would coolant burn blue? ahhaaha

 

valve guide seals

if you get blue smoke only at startup, that is your problem 100%. Old valve guide seals allow oil to seep down the valves while your car is not running, and when you start it all the oil is burned. And with the vacuum created by the engine, it is more than likeley to pull some oil down while the engine is running also, but you may not notice.

 

I dont know why it would burn blue? Maybe for the same reason that plastic burns black smoke? I'm not a major in chemistry, so I dont know what chemicals burn which colors. I just always thought blue was antifreeze. My mistake professor. You answer it, cause you do it best.