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-   -   Another Smoke Question:white But Only On Startup (https://www.nopistons.com/3rd-generation-specific-18/another-smoke-question-white-but-only-startup-28391/)

ichibandan 11-18-2003 01:20 PM

White smoke + sweet smell = burning coolant

Black smoke = running rich or improper combustion (or ATF if you're using that to clean things up)

Blue smoke = burning oil



EDIT: Wankels are totally new to me, so I can't tell you exactly where to look, but on a piston-based car, one would suspect coolant leaking into the oil. I'd recommend draining your oil to see if it's milky.

Sinful7 11-18-2003 03:43 PM


Originally Posted by naponome' date='Nov 11 2003, 03:48 PM
I mean after about 5-10 minutes. And everything is stock.

Mine smokes for 10 minutes on startup, on a new Mazda Reman. Although mine is definetly fuel, it still is a light blue color when it's frst started, after that, it barely smokes, and just stinks like gas. Always, always has.

Dragon 11-18-2003 04:14 PM

This is normal. When you first start the car it is cold so it doesn't get complete combustion till it warms up. Since it doesn't get complete combustion the computer also adds anywhere from 1%-30% or so of extra fuel depending on the water temp sensors reading in order to keep the engine running. So some of the smoke is unburned fuel till it warms up. ALSO there is water vapor from combustion as well and the colder it gets outside the more you will see it. The water vapor is at first hot from the combustion process and expands. Once this hot air full of water vapor hits the cold air when it leaves the exhaust system it will condense in to larger particles that will look like white smoke and then it will dissipate in to the atmosphere quickly and disappear. The colder it gets the more you will see it. It is normal and nothing to worry about.

ichibandan 11-18-2003 08:40 PM

Sweet white smoke is something to definitely start checking out. Ever open a bottle of Prestone and smell it? It smells good enough to drink! Just don't do it! lol But when you have sweet white smoke, that smell is from coolant being passed into the combustion cycle and out with the exhaust. For regular black or blue smoke, I second Dragon on his opinion. I wouldn't worry too much about startup behavior if there's a little smoke. It's when it's warmed up and still smoking that would be worrisome. If you're still running rich after it's warmed up, then the list of things I would go through in order of easiest to hardest would be: check to see if your plugs are fouled out, check for acceptable amount of resistance in plug wires, check if O2 sensor is clogged, check ECU for error codes. That's all I can think of off the top of my head. If that's all working, I don't know if FDs use AFMs or MAP sensors, but you may want to check the sensor to see that it's not giving an artificially high air flow reading which would cause the ECU to request more fuel than normal.

naponome 11-25-2003 12:04 PM

Cool thanks for the help....I haven't driven my car in about 3 weeks (stored in parents garage) but I will check out everything you guys mentioned this weekend.


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