Exhaust system?

Tiny
LITTLEBLONDIE
  • MEMBER
  • CHEVROLET CAVALIER
Chevy cavalier 2003, standard. Check engine light came on, got it checked out and it came up as an emission leak. Mechanic checked normal things. And turned light off. After a day or so, the light came back on. When I've been driving my car for awhile and I slow down or stop, it will make a "popping" noise from the rear. Not sure if it's really backfiring. Could it be my exhaust system is plugged, and if so, how do I check it?
Tuesday, September 11th, 2007 AT 12:31 PM

5 Replies

Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
A couple of things, first it would be of enormous help to have the codes, the engine size, and the mileage!
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Tuesday, September 11th, 2007 AT 1:07 PM
Tiny
LITTLEBLONDIE
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  • 3 POSTS
Sorry. It's motor is an ecotec 2.2 and the milage is 78,000. It's a 4 L.
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Tuesday, September 11th, 2007 AT 1:35 PM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Under today's EPA rules our cars can't burp or belch or fart into the environment, instead they are required to swallow these extra gasses back to the cannister and the gas tank, There is now about 2lbs of pressure in the tank and return lines, A part of the Computer monitors this system called the EVAP system, if the pressure drops, the computer sets the MIL, or check engine light, and set a numeric code in memory. With scan tools we can retieve thiese codes and fix the problem. In your case there was an EVAP code set, and we need to know what it was so we can suggest the next step! The popping noise may be related to a hole in the exhaust. Or perhaps a slight backfire.
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Tuesday, September 11th, 2007 AT 6:48 PM
Tiny
LITTLEBLONDIE
  • MEMBER
  • 3 POSTS
The code is P0440. If it matters any, I seem to have better gas mileage and besides the "popping" sound, it runs great.
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Wednesday, September 12th, 2007 AT 12:20 AM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
P0440 Evaporative Emission Control System
This type of code will require a visit to the dealer or at least a garage with a smoke machine, It is hooked up to the evap system and pumps about 2 psi of smoke into the system, when the smoke escapes the leak is found! Get it checked out!
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Wednesday, September 12th, 2007 AT 2:30 AM

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