HELP EGT Issues.

[Leadfoot]

Background

For the past four weeks I have been running the McRat tune or modified McRat tune and loving it. I have been watch EGT's towing my 5000lb trailer and they have been great as long as I kept the right foot in check. I towed my other truck to the pulls 6200 plus trailer and they were great (again using the right foot wisely).

Today I had a truck pull. I ran the tune at the pull and let the truck idle for half an hour after the pull (didn't pay attention to the guage). Shut truck down for two hours to take care of club business and clean up. On the way home on level road I'm going along at a sane pace (30 MPH) and just happened to look at the guages. EGT's pegged! I immediate pulled over put it in nuetral and the guage finally went to normal idle temp. Put on my blinker and slowly pull out and before I hit 20 the needle is pegged. I pull over, wait, pull out, watch EGT guage peg and repeat for several tries. Finally pull over and reprogram to stock tune with similar results (although the temp took a little longer to peg). Once I could get up to speed it was fine with the stock tune, but hills or trying to get on highway would PEG quickly. I slowed to 45 MPH and put on hazzards for two miles.

I'm assuming it a guage or probe issue (I'm hoping). Also before putting stock tune back in I logged balance rates and they are normal. The guage is an ISSPRO guage I got from Kennedy about 2 years ago.

Are guages/probes known to go bad....?

Please say that is my issue.

If the guage/probe is not bad what would cause that even with a stock tune and 20% throttle on a slight incline.

It makes me worry. Could I have cooked it pulling? If so why does it seem to work (by that I mean it goes from normal temp at idle and will swing full to the peg).

Sorry for the long post, just a little worried.

Thanks in advance.

 

[kodiak]

Whats the boost look like??

 

[bullfrogjohnson]

My probe went bad after about a year, It didnt do what yours is doing it just jumped around alot

 

[Leadfoot]

Sorry, just getting back online now.

I have been monitoring boost (seems normal and no leaks)

No black smoke out the pipe.

Question: I haven't heard the vacuum cleaner Swoooshing sound at start-up (the sound the truck makes when the vanes cycle). Could a bad sensor/actuator cause excessive backpressure and EGT's? If so, how would I check (no check engine light).

Also I placed second (3 feet behind) to an 05 LLY running the PPE Hot +2. I think he got me with his tires as he has a 4" Pro-Comp lift on 33's and I just have 265's that are worn.

How close are we (on paper) for power?

Whats the boost look like??

 

[rushingbc]

mine pyrometer does the same thing every once in a while, not sure why. I turn the truck off, try it again and it always seems to go away. I'm a lb7 guy though. hope it's simple

 

[McRat]

Pyro's have a high failure rate.

I doubt if anything is amiss if the truck is running good. When our trucks screw up, usually it ain't subtle.

 

[Killerbee]

it's impossible to have EGT over 800 F at idle. At least on THIS planet.

Ground issue.

 

[Leadfoot]

it's impossible to have EGT over 800 F at idle. At least on THIS planet.

Ground issue.

At idle the EGT's are normal (under 300 F).
It's as I start to move under load, up a slight hill, or accelerate at anything more than a light pace that the guage will peg.

I have a new probe coming this week, so I will be riding the motorcycle (just to be safe) until it arrives and is installed.

I know it's not overfueling as balance rates are good, there is no black smoke, and engine sounds normal. I checked the air intake and the guage is in the green (filter minder), so I am betting it's a bad guage/probe.

My curious mind was wondering if it wasn't a guage/probe, what would cause it and I came up with this list:

Overfueling (doesn't seem to be an issue)
Bad injector(s) (doesn't seem to be an issue)
Clogged intake (doesn't seem to be an issue)
Clogged exhaust (doesn't seem to be an issue)
Bad VVT (I don't know how to check this) Although I would think a CEL would come up?

Any other oddball things to check

 

[kodiak]

If your boost levels are normal.....My money is on the Probe.

 

[Leadfoot]

Update:

Replaced $40 pyro probe and all seems OK.

I removed the old pyro and other than a light coating of soot, there seems to be no apparent issues with it (other than it not working). Oh well, must of been my unlucky day.

Thanks for the input!