Had my car in the shop today, due to bad gas mileage!!! Found that the inside exhaust pipes are black, and you would think that the car was running rich. Hooked up the scaner and checkd every thing out only to come up short. Every thing looked good!!! Any help would be great!!!!!

Thanks Mark

Every exhaust pipe I've ever seen has been black inside. I'd be worried if it wasn't! Thats just carbon for burned fuel... totally normal.

It seems to be more than normal, the bright ble bumper cover is black also. Is that normal?????

OH NO!!!! Exhaust pipes are black inside, STOP DRIVING IT!!!


what did they check? maybe in open loop you are too rich and once in closed loop the intergrater corrects the fuel trim?

how long do you drive the car? driving habits? exhaust leak befor the o2, clogged cat the list can go on and on. how good is this shop? do they know what they are loooking at?

what is your milage?

All those things were checked!!! Car runs in closed loop, cat is fine, it all checked out!!! Mileage is 136,000

Mine had a thick layer of soot inside the pipe because it ran so rich for so long. My problem was dead sensors: TPS, O2 & some bad wiring.

Short trips and frequent start ups are the worst for black pipes.

I have a 2004 Pontiac Vibe that I drive no less than 20 miles per trip. And it gets driven 2 times a day. Once to work and once home. That alone is a 46 mile trip each way. Plus I live ~20 miles from any civilization.

Kissin' 40,000 miles on the clock and there isn't a hint of black soot in the tail pipe.

you never said what your milage is! not howmany rounds the car has
you never said if they know what they are doing (lots of shops have NO idea what they are really looking at, sorry if this hurts your feelings but it is the truth!)


if they checked everything and everything is fine then well sorry you asked us to help

they checked everything is fine, so we are no help since "all those things were checked!!!"

exhaust is not clean. U are supposed to have soot in your pipes. 100% normal. chill out. If everyhting turned out fine. it is cuz it is fine.

The Vibe is a new car. VERY different than a third gen, lol. Pull the header off that vibe. You will find some nice black stuff in there. I GARONTEE.

Thanks guys, i'm just gonna relax and let it ride.

Mark

Your rear bumper should not have black soot on it. Thats too rich in my books. Black pipes = good, black bumper also = not good.