1994 Mazda Miata white or light grey smoke on take off

Tiny
BLERMA
  • MEMBER
  • 1994 MAZDA MIATA
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 102,000 MILES
My wifes Miata throws out a puff of white or grey smoke at initial take off from a stop. This occurs after warm up but does not occur all the time. After cleaning the MAS, Throttle valve and replacing the o2 sensor, Spark plugs & wires, and air cleaner, the problem went away for approximately one month. Now its back but this time is puffing more often. Also when this occurs, the engine pings. This only happens on take off or first gear. After it shifts into second, everything is fine.
Thursday, October 9th, 2008 AT 3:44 PM

7 Replies

Tiny
JAMES W.
  • MECHANIC
  • 2,394 POSTS
Are you losing coolant over a period of time?
At an idle, after engine warm up, do you see bubbles coming up in the coolant reservoir?
What, roughly, is your oil consumption?
When you installed the new plugs, did any or all of them look carboned up or oily? This info will help narrow your problem down. At this point I'm thinking head gasket, cracked head or the motor is just getting tired. Please advise.
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Thursday, October 9th, 2008 AT 4:36 PM
Tiny
BLERMA
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  • 4 POSTS
Doesn't seem to be losing coolant between services. Is possibly less than half a quart low between oil changes, (3000 miles). Only #4 spark plug had slight carbon buid up.
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Friday, October 10th, 2008 AT 8:47 AM
Tiny
JAMES W.
  • MECHANIC
  • 2,394 POSTS
I would run a compression test on all cylinders and compare the results. You may find #4 cylinder is lower than the rest. Please advise.
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Friday, October 10th, 2008 AT 1:15 PM
Tiny
BLERMA
  • MEMBER
  • 4 POSTS
I did compression test with the following results: #1 190 psi, #2 185, #3 185, #4 190. All cylinders maintained pressure however #4 did show signs of oil in chamber. I cleaned MAS sensor and trottle body again and this seemed to improve condition. Drove around neighborhood and car didn't smoke at all. Took car on freeway and ran geat until I came to a stop after exiting. Smoke returned but seemed less as I continued to drive in residential area. Got back onto freeway with same results upon exiting. Could this have something to do with air fuel mixture or pressure?
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Tuesday, October 14th, 2008 AT 3:18 PM
Tiny
JAMES W.
  • MECHANIC
  • 2,394 POSTS
Compresson looks good, even exceptional for over 100K. Is your EGR valve and air pump working? If not, it won't affect the running of your motor but, it should recirculate some of the smokey exhaust and burn it up on deceleration. Just a thought.
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Tuesday, October 14th, 2008 AT 5:14 PM
Tiny
BLERMA
  • MEMBER
  • 4 POSTS
Cleaned EGR, doesn't have air pump. Tested EGR with vacuum tester and checks ok. Took it by a shop to get mechanics opinion. He thinks it's valve seals. He says the car smokes during warm up and very little when driving. I don't notice while driving and don't see smoke during warm up. If it was valve seals wouldn't it miss or foul plugs? And wouldn't it smoke and ping at every stop?
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Friday, October 17th, 2008 AT 7:25 PM
Tiny
JAMES W.
  • MECHANIC
  • 2,394 POSTS
Bad valve seals usually won't foul plugs unless they're "really" bad. It's normally low compression that fouls plugs. Try running it around the block a few times so it's good and warm. Shut it off and let it set for 20 to 30 minuetes and restart it. If you get a puff of smoke when you start it. It could be seals.
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Tuesday, October 28th, 2008 AT 2:14 AM

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