Here is my story. I had test pipes before that blew out both my o2's. I ran with no o2's for about 4 months (school+no job). I recently bought new megan test pipes and brand new o2's, thinking my car would run flawlessly like it did when I first put this set up on the road.

My car is spitting out tonnes of raw fuel from the exhaust in the form of white smoke. By tonnes I mean clouds fountaining out of the exhaust pipes and covering the street. This only happens when the car has reached operating temp and only at idle. After I set off, the car leaves behind a thick cloud of smoke and then leans out the mixture, until the next stop light where i come to an idle.

I have vibrant performance o2 fittings (They are non-foulers plugs with various diameters for the male end).

The car is a 2003 g35 coupe, 6mt. Apex-i WS2 catback, megan test pipes and y-pipe. Brand new rear o2 sensors were fitted last week, the car ran without smoke for a few days, then this happens.


There are no signs of a head-gasket leak, coolant is at the same level it was when i checked it last (8 months). Car doesn't burn oil and runs strong.


So I am confused. Input?


Thanks.



*edit

The car has 180,000 km's on it.

 

white smoke is not Fuel

Oil = blue
gas = black
coolant = white


With that kind of mileage who knows.

 

The rear O2 sensors do nothing except tell the ecu that the catalytic converter is doing it's job. Since you have no cats, you just threw your money away buying new sensors. I have no rear sensors on my car at all and it runs flawlessly.

Your problem sounds like it's oil related. How much oil is it consuming, if any?

 

Most people can't tell the difference between oil burning and coolant...but I agree it's likely not fuel.

 

Its easy to jump to conclusions and assume that white smoke indicates burning coolant. But things are often not as they seem.

My money says bad fuel injectors.

 

Unlikely as bad fuel injectors are rare and the smoke would be very dark. People tend to mistake coolant and oil smoke but rarely do they mistake fuel smoke.

 

I say fuel smoke because it reeks of raw fuel, and if the exhaust is hot enough, it will slightly combust. Burning coolant smells sweet, and from my experience, distinctly noticeable. But I could be wrong.


Initially I was thinking bad injector o-rings. But I want to eliminate all possible options before I tear apart the motor.


I also understand the rear o2's only shoot the message to the ecu about the cats. BUT, after I plugged them in, the car bogged less and pulled harder.


The car burns nominal amounts of oil. Last oil change, it measured 216mL burned. I change my oil every 3000km.


Let's keep brain-storming. What else would everyone need to know?

 

If it's fuel though it should be pretty black. Things that could cause the fueling to be rich is:

1) Bad MAF
2) Bad FRONT O2 sensors
3) Bad Coolant temp sensor

And maybe some other things that I can't think about right now.

In either case, you should have a CEL on with a " system too rich" code and maybe some others. Scan your car.

 

What do you mean blew out your rear O2's? Did your old test pipes blow up or something? All of this is going to be guessing you need the car scanned. My best would be something damaged the front O2's if it was perfect before this incident. With faulty front O2's the car will run pig rich to save the motor from ever running lean.

 

Smelling lots of fuel is normal with test pipes, the cats secondary jobs is to help burn un-used fuel. You are right about the smell of coolant burning, it is very different and almost sweet, not to mention very moist. Do you have any video of it?

 

It was more the low quality welds on the bung's and the quality of the metal. The pipes did blow up, essentially. I wish I had a picture, quite entertaining.


Zazz, I just got a new camera, still figuring out how to work it. I'll try to get one ASAP.

GT-ER, the MAF sensor was replaced a while ago. I reset the ECU yesterday, there is no check engine light, although I will scan it to see if there were any ghost codes. Well before any of this happened, I was running with a knock sensor low voltage code P0327. That went away after the reset.

I haven't considered front O2's or coolant temp sensor. The dealer told me o2's rarely ever go bad, and that apparently our cars are "Built with a knock sensor code"... I don't understand that. But I'm not about to get into an argument about Nissan's with a master tech.

Anyways. I will try to get a video and a scan.


Also, are front & rear o2's interchangeable?

 

The problem with interchanging the O2 sensors is the length of the cable...I doubt they will reach.

Scan the car and tell us if you have any codes.

 

IF you suspect fuel injectors you may be able to narrow it down to side 1 3 5 or side 2 4 6. If you disconnect the exhaust BEFORE a common pipe (Y or X) you may see smoke from one side only.

 

Smart idea.