Cat high exhaust temp.

I would say normal. Pulling an empty faltbed with mine it doesnt take long for it to get up around there on a hill, as long as your not keeping it there for long periods of time you should be fine.

 

I don't think that's normal, usually when EGT's run high like that, there is a boost leak somewhere

 

first check for a air intake leak, cac or a turbo boot. then pull the pipe off the turbo intake and look at the fins on turbo wheel. see if you can move it with your hand and put a little side pressure on it to see if it will rub the housing. those don't cost anything to check. another thing to try is set idle at about 1500 to 1700 rpm and squirt windex or soapy water on all the piping to see if it bubbles up if any bubbles that is a leak. you will only be making about 1 or 2 lbs of boost but it will be enough to find a leak, now think how bad that leak would be at 28lbs of boost or more. oh and squirt the elbow that comes off the turbo housing. those two O-rings have a tendency to leak also causing loss of boost.

 

oh almost forgot the cac you may have to pressurize to see if it is leaking. to much surface area to squirt with the bottle. has the air filters been replaced? just some ideas to try.

 

What rpm range are you pulling the hills at when this happens?

 

Some guys say Cats like to be lugged down. I have an 01 c15 (6nz) and I noticed that the temps do creep up even when empty if you pull much below 1500 for awhile say with the cruise on. The guy who owned the truck before me said the same thing. 1500 on up temp is fine.

 

When I'm pulling a hill with mine I keep it between 1500-1600 on a long grade with the fan on, pyro has yet to go over 900 doing that, below that it will get up to 1000, but I have never pushed to see how high it will go.

 

Yep. Well, almost, I have to actually get up to 1800-1900 in order to get the next gear, if outside temp is, oh, say 75 F or warmer. Having a C15 mbn which is now a 1mm, I have to drive it totally different, just like an old 80's truck. And, when up shifting, never even think about the next higher gear til the egts are back down to 810 or so, or there is no use, she'll be over 900 headed to 1000 in no time. Took a bit of getting used to this, but, really, for pulling 140,000 lbs, lots of power, and it actually sounds a lot better pulling at 1600 than it used to at 1350. So, to op certainly check out the things as suggested, but, it there may not be anything wrong, depending on what your pulling, etc.