This weekend i made a trip to illinois from north carolina pulling a pretty light load. I had unplugged my quad XZT to try and be nice to the tranny for once, and was pulling maybe 6500 lbs on the way back. Coming through the mountains of West Virginia i was noticing some strange EGTs. If a hill caused the truck to shift down into Drive, the egts would get high quick. It was all i could do to feather the throttle just right to maintain speed and keep the EGTs in check, this was driving maybe 65 to 68 mph. They were very easily hitting 1350, and would go over 1400 with just a little more throttle. Then i noticed if i hit a hill just a bit faster, like 70 or so, i could hold overdrive and the EGTs would not get over 1275 or so, and that was gaining speed up the hills, and into the throttle pretty good. I have always thought that keeping the rpms up, and dropping down a gear in the hills would help egts, but somehow it makes mine much worse. Any ideas?


The truck was making good boost, 34 to 35lbs in the hills, so that should be plenty to keep a stock truck cool, and i have a BHAF, which i dont think makes much of a difference.

 

Same here for me, on my last trip down the Oregon coast, few good hills. I would hit the high EGT like you described on the down shift. Just another wierd one to me. Didn't concern me much though.

 

Towing in the mountians is usually the opposite. Holding in OD will cause the EGT's to skyrocket, so you have to play throttle games to hold the truck in 3rd gear. Dodge really dropped the ball by not having an OD lockout from the factory if you ask me.

 

throw on a water/meth kit to help out, the DevilsOwn does an awesome job for me.

 

Normal. The ECU fuels more at higher rpm's. In this case turning the Quad back on will benefit you by keeping the trans in OD.

Not on a CR with stock fueling. Holding OD is the best way to keep EGT's down. Not as much fuel being injected for the air the turbo is capable of flowing.

 

Don't get me wrong, I'll be the first to let you know that I'm no diesel expert, I can just tell you what my truck does.

My '05 is stock except for AEM workhorse filter and muffler delete. I've towed my jeep/trailer (approx 6K lbs) up the I-70 passes here in Colorado many, many, many times, and see the same results everytime.

If I try to maintain speed (65-75mph) up the passes in OD, my EGT's will peg my gauge (1500) in the blink of an eye. If I mash the skinny pedal, the truck will then downshift, and I then have to find the sweet spot with the fuel pedal to keep it out of OD. When the truck downshifts, the EGT's fall quickly to a safe zone, and remain there for as long as the truck stays out of OD.

 

Hmmmm...this is exactly opposite what I see. Pulling 10-15k on short or long 6-8% grades keeping it OD is the only way to keep the EGT's under 1300. This is with Smarty on SW#5 also. Stock is the same way, only, it won't hold OD and downshifts, then the EGT's spike close to max. However, this is mostly 4000 feet and lower.

What mods or power adders do you have? Maybe the elevation is the factor here?

 

I was at less than 3000 feet the whole time. It really bugs me that a completely stock truck will run the EGTS up that high. I mean, how many people out there dont have gauges and just hammer on their trucks up every hill? I used to, and never had a problem. Sometimes i think about just selling the Quad box, and selling my gauges and just drive the truck, and not worry about temps......

It just doesnt make sense, i was only pulling 6500lbs, and not running 90 mph, just a normal drive up some hills with a moderate load.....

My old 01.5 was sold with 219,000 on it and never had an egt guage, and pulled 15k on a daily basis. I wonder what the temps were on it? Never seemed to hurt it....

 

A big difference in trucks though, 215 HP compared to 325 HP, no emissions to emissions engine. It do tende to drive the temps up, especially when the 3rd event kicks in.

Cummins claims they are good to 1400 degrees on EGT's and they don't seem to mind it. It does sound a bit high though, check filters and see if there is a problem.

 

Who at Cummins has actually said this? Everyone I know that's asked has gotten the same generic response with no actual numbers mentioned.