Burned rear bumper

[Bickford]

Hi all,



Has anyone else ever noticed a discolored blue to black Exhaust burn mark on the right rear corner of the stock Chrome Bumper? Kind of looks like a 1970's discolored / blue burned chrome header pipe on a BMW motorcycle. The Blue Burn / Heat Mark measures seven inches across by four inches deep.

While on a New York to Florida fifteen hundred mile trip. Towing a empty twenty five hundred pound Trailer at around seventy five miles per hour. With less than one thousand pound load inside the Truck. I noticed the check Gauges light would flicker on for a few seconds then go off. I stopped and checked all of the Fluids which were fine. Then double checked all of the Idiot Gauges and Lights which were A / OK. I previously had the Speedo / Dash cluster replaced under Warranty >>> The Transmission Temperature Light would flicker on and off at the five hundred mile mark.



The only odd thing that I have noticed is that my electronic engine temperature gauge at times only rises to the one quarter temperature range. ( when the Truck is running in eighty five to ninety degree Florida heat). This Truck has had the Fuel Filter changed less than two thousand miles ago. The Engine Oil and Oil Filter has been changed every four thousand miles. Now at eighteen thousand miles the Truck seems to run better all the time.



Any ideas or concerns with the rear Bumper?



Could my AFE drop in Air Filter be causing a lean Fuel to Air Ratio?



2003 Dodge HO CTD 3500 six speed SRW LWB SLT Black four door AFE drop in air filter ARE topper. loud Clutch Disk replaced, leaking rear axle seals replaced, leaking third brake light RTV resealed, Otherwise 100% stock.



Take Care and God Bless, Earl

 

[rbattelle]

Many of us have the same bluing effect. It just wipes off, though. No worries. Actually, I sort of like it... kinda reminds you of just how much heat you're generating!

 

[RAMINSPEED]

I get it also, I think it's just soot residue. It just cleans off with some solvent and a rag. Welcome to Diesels.

 

[Joseph Donnelly]

Diesels don't run stoichiometrically. At idle, they may be 80 or 100:1 air:fuel, for example. So, a filter can't lean it out.

 

[dPierce]

stoichiometrically....WTF???

I need another cup of coffe before reading words that big. I'm blowin' the dust of the Webster to translate this into my simple hillbilly brain.

 

[rbattelle]

Basically, a stoichiometric fuel/air ratio means that there is exactly enough fuel and air that the combustion reaction results in no excess air or fuel. In other words, complete combustion.



In general, engines run at peak power and efficiency at the stoichiometric mixture. Unfortunately, they run way too hot, and the combustion cannot be controlled so it runs to completion in most applications. So they run lean (too much air) instead, which lowers temperatures and ensures most of the fuel finds some air to react with.

 

[Prairie Dog]

A simple turn down tip on your exhaust will solve the blue soot problem.

 

[Bickford]

Thank you for all of the fast Burned rear bumper replies. I guess I have spent to many years working on two and four stroke motorcycle engines.



Now if I could just get my built up 1969 440 cubic inch Plymouth Road Runner to go beyond six miles miles per gallon...

I do so enjoy the fuel mileage from this heavy old 2003 Dodge Cummings truck.





God Bless, Earl

 

[Phil Howell]

My white Sport gets a sooty black area behind the pipe. It wipes clean easily.

 

[MCummings]

More Air = Cooler EGT

More Fuel = Hotter EGT



What you want to do is get the most of each



Put some more air, then some more fuel, then air, then fuel, untill it's so addicting you can't stop.



Merrick Cummings Jr