exhaust fume smell

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exhaust fume smell

mikeyZ06 mikeyZ06
I watched Corvette Summer | Posts: 6 | Joined: 04/13
Posted: 04/16/13
04:38 PM

I just purchased a black 2002 Z06, this is my first vette, I always wanted one. After i have had it out for a drive and have parked back in my garage I notice an odor that smells like exhaust fumes even after sitting for a couple of days the smell is still strong, There are no lights that come on and the car runs nice. Please help  

waynep712222 waynep712222
Cross-Fire Crazy | Posts: 35 | Joined: 04/13
Posted: 04/17/13
07:48 AM

you should NOT have any smells from these..  especially those that linger..

are you sure its NOT a FUEL leak ?????

or a fuel vapor leak...

how about wiping a paper towel around the inside of the tail pipe opening.. there should only be a LIGHT TAN or LIGHT grey residue... if any.... if the inside of your exhaust pipe is black with soot.. or black with a oily residue.. then you might have other issues..

do you have the ability to look under your car...  or have the underside inspected at someplace easy like a drive thru oil change place .. where they drive the car over a PIT in the ground instead of jacking it up or on a side post lift..   have them look for leaks... and for things stuck to the exhaust system..  and burn marks on the underbody from the exhaust system.

depending on where you live.. smog shops might be able to run the low pressure evap system pressure test..  where the proper hose at the front of the car is pinched shut with a locking pair of long needle nose pilers... the gas cap is removed and tested for pressure and vacuum.. an adaptor cap is installed on your car and the calibrated machine is hooked up.. inert gas.. usually nitrogen is allowed in at 1 PSI then the valve is closed and the pressure monitored by the evap system testing machine..  if it has even a tiny leak...  in the fuel or fuel vapor containment system.. this will find it...   companies like stant.. who makes thermostats and radiator caps.. also has a hand pumped evap tester.. some parts stores might have these in their loaner tools..

lastly... since you say the check engine light is not on..    does it work??? it should come on for 2 or 3 seconds when you start the engine...

if not.. then the bulb is burned out or somebody removed it..  yep does happen..

you can also plug in a scan tool.. . and check for codes.. look at the live data stream...

look closely at the various live data streams..

look at the short term fuel trims  and the long term fuel trims..

they should be on a good running car be within plus or minus 10%. while idling.. and with a steady foot while cruising on  a level surface at legal speeds..  they do vary when you get into acceleration..  or slowing down.. best to have a passenger monitor these.. or set up the scan tool to take a freeze frame recording ...

if you don't have an OBD2 scan tool...   your 2002 is OBD2... and there are a LOT of options..

the least expensive one that does work is the harbor freight 98614..  its just generic so it only does engine and basic transmission data.. but its cheep compared to many of the others that only do similar systems.. you would have to go to a around 500 bucks to get a half way decent OTC 3499N set..   if you are PC LAP top friendly..  there are USB adaptors to hook up..   be carefull of knockoffs of these..  check the tail pipe... and look under the car first..  

mikeyZ06 mikeyZ06
I watched Corvette Summer | Posts: 6 | Joined: 04/13
Posted: 04/18/13
08:36 AM

Thanks for the great info. I had a mechanic friend scan the engine and the only code that came up is P0175 fuel system too rich bank 2. We cleared the code and i will drive the car for a bit then re scan to see if the code comes back. I went out to the garage this morning and the smell is not as strong as before. This car sat for awhile, not sure how long and had less than 1/2 tank of gas when I bought it. I filled the tank with premium gas and will run it very low and try a full tank of new gas and see if it helps.  

waynep712222 waynep712222
Cross-Fire Crazy | Posts: 35 | Joined: 04/13
Posted: 04/18/13
07:24 PM

with an OBD2 scan tool... some will show more than codes.. some show live data... some actually will GRAPH some of the data streams to see if the sensor voltages are doing what you expect them ..

more later tonight or in the morning..  its been a LONG day on my end .

can you post the brand and model number of the scan tool you have??? so i can look up an instruction booklet .. see if it can view live data stream..

P0170 - Fuel Trim Bank 1
P0171 - Fuel Trim System Lean Bank 1
P0172 - Fuel Trim System Rich Bank 1
P0173 - Fuel Trim Bank 2
P0174 - Fuel Trim System Lean Bank 2
P0175 - Fuel Trim System Rich Bank 2

look at the oxygen sensor voltages..

are they swinging constantly from 0.10 to 0.90 volts... or close to that.. not steady or barely moving.. if the numbers are not constantly moving when you hold the throttle at 2500 RPMs..

you might have a bad oxygen sensor..  that would be the first one on the passenger side..
usually right at the header..  

check for vacuum leaks around the intake manifold..  cracked vacuum hoses...

with the engine idling.. find the vacuum hose to the fuel pressure regulator.. pull it off the intake if you can.. there should NOT be fuel in there... if you had a P0172 and a P0175 that would more than likely be where to look at..

check for exhaust leaks also... or cracks in the headers... or blown out manifolds..

again.. check the oxygen sensor voltage .. swinging..  

pepsi1 pepsi1
Duntov Incarnate | Posts: 88 | Joined: 01/12
Posted: 04/19/13
05:35 PM

Does the exhaust smell like rotten eggs, or sulphur? If it does something is making the system dump more fuel then it needs...

  I had a different type problem with my brother's 2002 Z06. He didn't say if the exhaust smelled. It turned out to be an "O"Ring on one of the L/Bank injectors that had to be leaking and sucking the slightest amount of air. (Which injector I couldn't tell you). The O Rings all looked the same. That was all I changed. I recall that same Code. (P0175)

  IMO it was just something that made that cylinder want more fuel. So it was really lean in a sense. Replacing the O Rings stopped the air leak. Then it tried to correct itself by needing more fuel. It had 34,000 miles on it. The dealer had it deleted the codes and sent it back out. Remember its a Z06 Corvette, and they are a breed of their own...LOL...
  The smell is usually when the engine goes rich, and the Cat is try to digest it. So it gets smelly. I've noticed these newer imports smell like they did back in the early days of the Cats. That stinky Sulphur smell...


mikeyZ06 mikeyZ06
I watched Corvette Summer | Posts: 6 | Joined: 04/13
Posted: 04/21/13
12:53 PM

we scanned the car with a Snap on Versus tool and checked the live streams and everything looked great, Since putting in some 94 octane and injector cleaner the smell is gone, The car works great. thanks againg for the help.