Well....... I got 290 miles on 21 gallons, 13.8 mpg, pretty crappy...... o well, about half of that was towing so it wasnt THAT bad but on my exhaust there is a TON of carbon deposits..... My chrome tip is turning black and working its way around it.... not good, it whipes off but it comes back in about 20 miles. So i talked to my service guy and made an appt, and its going to be tested for running rich. know they get bad millage but the carbon deposits? it did this before i got my exhaust but i never really noticed it because i didnt have my chome tip. bty my truck is up to 5 k miles. anyone else have this problem?

 

Some black deposits in and around the tail pipe is normal. I would think that a rich condition should be throwing an OBD code and your MIL should be coming on. But, maybe not??? Let us know what the service guy says.

 

I just had some SS exhaust tips put on my truck about 900 miles ago. The insides of the tips are covered in a thin black soot as of now. So I think it's normal. Nothing to worry about.

 

Just to note. I asked Mike T. over at the Superchips forum about this issue (black depoist on the inside of the tail pipe) months ago and he informed me that it was indeed normal with these modern engines and how they are set up to run.

Use to be years ago that was considered bad, and as you say perhaps running rich, but not with todays engines.

If you have never heard of Mike T. over at Superchips he does a lot of performance testing with F150 and other products so he really know's this field.

 

Hi 01 XLT Sport & others,

Just some quick additional feedback, what 01 XLT Sport said is exactly correct, it is perfectly normal to accumulate some black coating of soot inside the tailpipes in modern vehicles.

Now in sdf150guy's case, doing that towing *does* increase those deposits, that happens when you increase the load on the motor. What's happening is simply that the motor is having to endure a much heavier load, so it;s burning more fuel, thus more deposits in fewer miles as compared to when not towing. Again, perfectly normal.

I don't like depending on Check Engine (SES) lights to alert me to a lean or rich condition, as while that *usually* works, not *always*. It usually works well enough to protect you from a gross piston-melting lean condition, or from a spewing smoke gross over-rich condition, but that's about it.

It will take a run on a chassis dyno to actually test the A/F's, or, if the dealership actually had a wideband O2 (and they never do, by the way, as that's an expensive tuner's tool primarily, so only shops like us use them) meter, they could connect it and run the vehicle down to road, but a dyno is the best way to test A/F's, so you can have a properly printed plot.

From the sound of everything, I think you're probably ok there, sdf150 guy, without looking at the vehicle this all sounds pretty normal.

Good luck!

 

thanks guys, its being tested tomorrow morning anyways because i did have the light come on today for a brief of period of time. so i dropped it off, and btw the black was ALL over the outside of it also, so i think that was part of it, but thanks for all your responces and i will keep you guys updated in the morning...