Exhaust smells like unburn gas on cold start?
Dec 1, 2015, 10:40 PM
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Exhaust smells like unburn gas on cold start?
Hello everyone! Like the title says, lately ive been noticing that when i first start up the car there is a slightly strong fume coming out of the exhaust.. It smells like gas, but it usually goes away after the car have been warmed up?
i got the car with a cat back exhaust that is definitely have been broken in. can anybody please tell me whats going on?
i got the car with a cat back exhaust that is definitely have been broken in. can anybody please tell me whats going on?
Dec 2, 2015, 09:08 AM
#4
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Cars run rich when cold to warm up faster. Its normal.
Dec 2, 2015, 02:15 PM
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Car just passed smog. Cat is definitely still on. No other modification other than intake and a cat back exhaust.
Anybody having the same issue, is this normal? Sorry for being a noob lol. Its my first Evo/turbo car
Anybody having the same issue, is this normal? Sorry for being a noob lol. Its my first Evo/turbo car
Dec 2, 2015, 02:40 PM
#7
Unless you have a fuel leak somewhere, this is totally normal.
As mentioned earlier, on cold starts cars run rich to warm up the engine faster. When the block temps are cold, injectors have a difficult time keeping fuel atomization consistent as fuel tends to stick to the cylinder walls/intake runners. The solution behind that problem is simply to add more fuel to allow for better combustion in the cold. Once your engine is warmed up and your o2 sensor is hot enough to take accurate AFR readings, your fuel enrichment will back off and you will run leaner again.
-pal215
As mentioned earlier, on cold starts cars run rich to warm up the engine faster. When the block temps are cold, injectors have a difficult time keeping fuel atomization consistent as fuel tends to stick to the cylinder walls/intake runners. The solution behind that problem is simply to add more fuel to allow for better combustion in the cold. Once your engine is warmed up and your o2 sensor is hot enough to take accurate AFR readings, your fuel enrichment will back off and you will run leaner again.
-pal215
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Dec 2, 2015, 07:00 PM
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Unless you have a fuel leak somewhere, this is totally normal.
As mentioned earlier, on cold starts cars run rich to warm up the engine faster. When the block temps are cold, injectors have a difficult time keeping fuel atomization consistent as fuel tends to stick to the cylinder walls/intake runners. The solution behind that problem is simply to add more fuel to allow for better combustion in the cold. Once your engine is warmed up and your o2 sensor is hot enough to take accurate AFR readings, your fuel enrichment will back off and you will run leaner again.
-pal215
As mentioned earlier, on cold starts cars run rich to warm up the engine faster. When the block temps are cold, injectors have a difficult time keeping fuel atomization consistent as fuel tends to stick to the cylinder walls/intake runners. The solution behind that problem is simply to add more fuel to allow for better combustion in the cold. Once your engine is warmed up and your o2 sensor is hot enough to take accurate AFR readings, your fuel enrichment will back off and you will run leaner again.
-pal215
Cool, thanks for clearing it up! No fumes inside the cabin or the engine bay. The fumes are comming straight out of the exhauast tips, and like i previously stated, smoke is colorless.
Dec 3, 2015, 04:57 AM
#9
Evolving Member
I forget that there is such a thing as cold startup. Haha, I'm in an area that's 80 plus year round so I have never once smelled gas on startup. Good to hear it's normal operation on your car!
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