1998 Nissan Sentra Smoke out of tailpipe---vacuum modulator

Tiny
SEANFIELDS
  • MEMBER
  • 1998 NISSAN SENTRA
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 122,600 MILES
I just had a tuneup and oil change by my mechanic. He also tested compresion and said all's fine. 140 across. Valves good no need for adjustment. He also cleaned fuel injection system. Then I drive home and smoke starts coming out of tailpipe. I figured it was carbon. I return car next day after smoke continues and runs sluggish losing power. He says it could be a bad vacuum modulator. But, I'm worried about credibility as I've never had any smoke and he gave car clean bill of health within the 24 hours of the smoke beginning. What is up with this? The car is in his shop for the weekend but I'm concerned and anxious. What could this possibly be?
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Friday, February 15th, 2008 AT 9:19 PM

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Tiny
RASMATAZ
  • MEMBER
What was the color of the smoke? You sounded like its gonna cost you an arm and a leg. What vacuum modulator is he talking about I hope its not the tranny.
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Saturday, February 16th, 2008 AT 3:16 AM
Tiny
RASMATAZ
  • MEMBER
Inbox : Message
From: seanfields
To: rasmataz
Posted: Sat Feb 16, 2008 4:50 pm
Subject: Vacuum modulator and color of smoke
It was grey and maybe blue. My mechanic said it was oil burning. He said the Vacuum modulator when it goes bad burns oil. It's a trans part. My question when he cleaned the fuel injection system could he have done something wrong and created the problem? When I first drove the car it seemed to lose a little something when I got it home after driving 50 to 60 miles then back down to a stop and going again it seemed to want to stall right around 20 but would pick up. The next morning is when the smoke happened. It's not a steady stream of smoke just happened 4 or 5 times before I got it back to him. I probably drove the car 20 miles at least before returning to his shop. Could there be damage to a piston or a valve due to a fuel mixture problem with the fuel injection system after he cleaned it.

I don't think the injection cleaning will caused the smoke

If the vacuum modulator is leaking transmission fluid will be drawned into the intake and get burn in the combustion chamber and as a result it will produce a whitish looking color.

Bluish color is an indication of oil being burned-get the engine compresssion checked to identify a problem with valves and rings
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Saturday, February 16th, 2008 AT 5:16 PM

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