Within the last few weeks I have pulled my truck and trailer out of storage to prep for the season.

I noticed a curious thing taking my trailer from home to service center and back for motor vehicle inspection.

Exhaust gas temps seem to be running 150 to 200 degF hotter than last year under load. Let me explain - the route to and from the service center is the same one I use every year , there are some substantial hills to climb going in both directions.

As an example , one particular hill last year EGT's reached a max (briefly) of about 1050degF , this year same hill EGT's hit 1200+ again for a brief period , say less than a minute. Engine oil and Transmission temps stayed normal and analog dashboard gauge did not move. I have an Edge CTS I am using for gauges - EGT temp is coming from a probe connected directly to the Edge unit , the other temps are from the on board PCM which the Edge unit is plugged into.

Can it be the probe is "bad"? It's about 4 years old. Any other ideas or suggestions as to possible culprit? We are headed out for a long trip in 3 weeks and I'd feel better if I could get to the bottom of this before we hit the road.

Thanks,
Retreever

 

Yes the probe can be bad, but if the exhaust is indeed running hotter, that's usually a sign there is fuel getting into the system and burning. I've actually seen catalytic converters start to glow red when this happens.

 

Well, outside air density also plays a roll in how your engine performs, so if it's cooler, on the day you hauled your trailer this year, than it was last year when you hauled your trailer, the cooler air would cause the fuel management system to supply more fuel to the engine, causing the exhaust temps to rise a bit.