C15 High EGTs

A few more things i should probably mention. The truck was sitting a a body shop for 3 months waiting to get the frame sandblasted and re painted. Before sitting there were no issues. The high EGTs were noticed on the second trip after getting the truck back. Possibly related from sitting? I dont know but it wasnt a slow progression of the EGTs getting hotter and hotter. One day they were good the next were not.

Also the truck does have an appointment to go into the shop but we've got another one in there currently so it will probably be 2 month before this one has a slot which is why i figured i would ask for some suggestions.

Since the high EGTs were discovered the truck hasnt been out of the yard. I dont want to risk melting anything so its just currently sitting.

Idling temp is generally 350ish

The other day i had to move a trailer in the yard (unloaded flatbed) so i used this truck. Just moving the flatbed from one side of the yard to the other the EGTs got to just over 500. On any other truck we have the EGT gauge wont even budge when moving an unloaded trailer in the yard

As i said above this wasnt a slow progression of the EGTs getting hotter and hotter. All of a sidden it was running hot. Ill check the radiator out tomorrow and wash it and see if it makes a difference.

 

Sorry for the delayed response. I had to do a couple runs earlier this week so I didn't get a chance to work on trucks in the yard.

I checked the air filters and they look new inside and out. I checked for CAC leaks with soapy water and there's none. I switched gauges and EGT probes with the sister truck. No change. I high idled but trucks in the yard and shot each part of the turbo and both trucks had temps within 10 degrees of each other. The elbow with the probe in it, the exhaust side of the turbo, the inlet side of the turbo, and the bearings. Both trucks had same temp.

I took the truck for a test drive for a long time and the gauge was showing up to 900 degrees when I was bob tailing. Here's where I caught a break. I got it reading real hot (900 degrees) and when I pulled up to a stop sign the gauge stuck at 900. I pulled over real quick and shot the turbo elbow with a infread heat gun. It registered 350 degrees. I went into the cab and the pyro gauge said 800. I went back and fourth a few times and the elbow temp with the heat gun went down to 325 degrees. The pyro gauge stayed at the same point. I went to turn the truck around and hit a pot hole. The gauge seemingly got unstuck and shot way down.

So I've come to the conclusion the temp reading is inaccurate. I've put a known working probe and gauge on the truck. I think either the computer is sending the wrong temp to the gauge or there's a chafed wire somewhere causing a bad reading. So now I need to figure that out but at least the engine is running correctly.

 

With the vintage 359 all the the gauges on the dash are wired together. I assumed they are all fed data through the computer

 

I'll take a picture and post it tomorrow but all of the gauges are wired one to another. There's probably 10 gauges all wired toghether one to the next