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I have an Infiniti G35, 2004, 6 cylinder. Every morning when I start the car, it smells gas. I believed due to incomplete combusion. How do I fix this?
What have I done so far?
Had a smog check done about a month ago. It just passed, at the borderline. I speculate the O2 sensors need to be changed? Never change b4. I had changed the spark plugs. The aif filter is clean. Engine oil is change regularly.Any idea why it still smell gas? Once the car runs hot, I smell less gas. Any help is appreciated. Thanks!!
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How many miles on the car? check engine light on?
start with a power balance test.do it both ways.
fuel and spark.It’s could be a vacuum leak and a defective O2 sensor that give no reading for the computer .
The O2 sensor It’s a probe that give you the amount of oxygen. If the computer cannot know how much o2 is use then the compulsion is not perfect (excess gas in the cylinder) and you will have more gallon / miles. For the vacuum leak It’is can be the reverse, you might have a gas or a air leak in the system, your computer will request more gas to try to have a perfect explosion because you have too much air. At the end both give you bad gallon / miles.But whiteout inspection you cannot pin point the problem.
[video]http://www.youtube.com/watch?v=9CPqbaSgcok[/video]
[video]http://www.youtube.com/watch?v=iR18rCvsKlY[/video]
Thank you so much for the replies. First, there is no engine light on. Mileage is now 222,650. I view the videos, the power balance test and vacuum leak test. Seems it’s pretty risky to check the vacuum leak if there’s a high risk of catching fire. Since I don’t have the fire extinguisher for standby, it may not be worthwhile to buy one (might as well pay for the test).
Anyway, if I want to change the O2 sensors. How do I ascertain O2 sensors are the cause? And, how do I change the sensors? Any special tools needed for Infiniti G35? Generally speaking, I know there are a few sensors for Infiniti G35.
Speaking of engine light, I know how to use the OBD II Code Reader to read the errors codes. Can I use the code reader to diagnose the incomplete combustion? What do I look for?
A code reader will not read anything but trouble codes.
a scanner will read live data or freeze frame data.this is
what you want.Lets not change any sensors or parts until
we gather enough evidence to do so.Start with the power
balance test.here is a video for vacuum leak testing using
water.no scuba gear required.The O2 sensors are not even active during start up so I believe you’re wasting your time there if you’re looking for that to solve the problem. Changing the O2 sensors may help with fuel milage but once again they’re not even looked at by the computer when starting the vehicle. It takes some time for the O2 sensors to warm up enough to function properly. The smell may be normal. Especially on cold mornings the engine is suppose to run rich and you may smell gas during that time.
Terence, if you want to do a vacuum leak test why not do it the safer way and just hook up a vacuum gauge to your engine and see that way? A sound engine should put out 15-22 inches with a steady needle.
There are 2 issues with that:
1. How do you hook up the vacuum gauge to test it.
2. What’s the estimated cost to get one. Or even rent one?In Mar 2011, my engine was stalling (surging during acceleration). Had the mechanic check it out. It was a vacuum leak at the throttle body gasket (TBG). Very simple gasket to replace but the diagnostic was pretty difficult. The mechanic pumped colored smoke into the engine (I think the vacuum system) and colored smoke came out from the TBG when running the engine. I don’t have that kind of equipmt to do that. It cost $30 just to blow smoke?! :ohmy:
You could also just spray water on the engine to find a vacuum leak. I’ve done it, it does work. It’s not as effective as throttle cleaner but it will work in a pinch.
Something I don’t think I mentioned before. Your engine WILL run rich when you first start it up. It’s designed this way. A cold engine doesn’t burn fuel as well as a warm engine so they run it rich till it warms up. The item in control of this ‘cold start mixture’ is the coolant temperature sensor. If it’s not too difficult to get to you might consider changing it at that mileage. If it’s readings are off it can cause it to run a little TOO rich during start up. BTW, I’d recommend an OE part for this for best results.
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