I have 2003 g35 coup and always noticed a carbon builded up on the tail pipes. I had the car check out by the dealer and the computer states {it's normal). About a year ago I installed a Z tube, with the large cone filter, and yes I had carbon builded up. About 2 month ago I removed the large cone filter and replaced it with a carbon fiber cover and inside a smaller cone filter. I maybe me going nuts, But the exhaust tail pipes, starts to build up carbon on the tip of the tail pipes, going 30 miles. With me finger I can remover it, it not really bad and I can live with it. The Car run great. So the question is: When does your car starts getting carbon Builded up on the tips of the pipes?

 

That's weird. You get carbon buildup when your car is running too rich. but you installed a higher flowing intake...should reduce the amount of carbon deposits.

 

Well, it really comes down to what the MAF is telling the ECU and what the ECU wants to do with that info. If the MAF sees more air then the ECU will compensate with more fuel.

This really isn't the right forum for this question BTW.

 

This really isn't the right forum for this question BTW.
Where would you put it?
I like your answer to the problem and I spoke to the dealer and the mechanic and they said, That's normal for this car. Some, will not got build up or very little and some, you will see more. If there computer does show anything and there is not TSB's on the problem, they call it "No Problem and that the way it is."

 

Well I probably would have put into the tech and mod forum. Since this is the mod review forum it generally should stick with reviews of specific products.

I'm curious though, did the dealer check the A/F ratio or did they just check the codes? I'm not sure if you can check the A/F ratio through the diagnostic computer. You may want to take it to a shop and have them check your A/F numbers.

 

That's what I'm going to do. What should the A/F read?

 

my exhaust tips also get dirty quickly? no engine problems noticed though. I figured I didn't clean them often enough.

 

i have a stock 6spd.coupe.. i also have the carbon build up on the tips.. i usually see it mostly during the winter.. i thought it happened because of the temperatures of the exhaust pipes during winter..

 

I'm guessing Air/Fuel ratio...?

 

Yup, air/fuel ratio. I'm not sure what the factory setting would be, but I'd bet that it's between about 12.2 to 12.7. That is slightly rich, but it's on the safe/reliable side that manufacturers tend to stick with.

 

that's normal for me also. i alway clean the tips when i clean the car.

 

Yup, I believe around 12.5 is right.

 

How many miles does it take to build up, and does it build up on the inside or around the tip's outside? I cleaned mine at 4000miles even though they looked clean and there was hardly any carbon. Now 1000 miles later they are still very clean. Maybe it has to do with your intake (my car is stock) or maybe it' just different with every car as alsg35 said...

 

maybe its also dust and soot, from the ground... ???

 

I find that for stop and go city driving, the carbon sometimes builds up a bit on the inside of the tail-pipes of most vehicles I've driven, especially in colder weather.

Usually I like to take the cars out for a 50 mile or so drive out on the highway at least once a month and by the time I get back, there is a nice light grey coating instead. The road trips can be a fun way of exploring some of the neighboring countryside!