1994 Mazda 626 GLX four-door 5-speed. Could not enter model information above as drop-down list does not display anything other than 'Choose a model'.
Interesting conditions here. Smoking is main symptom, and only occurs on an overnight cold start-up. Does not burn/use oil when fully warmed up. Thus, problem symptoms only happen in open loop operation. No check engine light is displayed normally, and when it does, a shut-off and restart clears the unknown trouble code. Trouble code only appears at the end of the warm up cycle, and not before.
Idle is stable at 750 rpm. Fast idle is about 1500 rpm, and stable.
Smoking will last about five to seven minutes. After that, no smoke. Exhaust smell is very similar to hot tar? Very little oil smell. First appearance of smoke is distinctly whiteish, then then turns a light blue. When the engine is almost fully warmed up, will leave a noticeable oil smoke trail behind.
Oil usage is about 700 miles to a quart. No visible leaks on engine or oil pan. Engine is clean. Engine is also quiet, no ticking or knocking can be heard.
Antifreeze level is stable, and when radiator cap is off, a little pushes out until the fan runs as the radiator gets hotter, and then it drops right back down. Do not see any fluctuation in antifreeze level when run this way. Replacing fluid lost is about 1/8th quart.
Leaking fuel injector? Worn valve guides? Worn rings?
Two years ago, ignitor assembly went out on distributor. Replaced distributor with rebuilt. Did attempt to start car when part failed for about five minutes. Then had car towed to repair shop.
This has been going on for about a month. Seems it smokes more when ambient temperature is lower, say, 30 degrees.
When this happens, shut-down and checking oil level at dipstick shows about a 1/4 quart drop after a severe episode. I let the engine run until the smoke is gone, and it still smokes blue smoke for a minute or two after when running the car down the street.
Sometimes very little smoke appears on cold start.
Wednesday, October 26th, 2011 AT 7:43 PM