Looking for for help with low power issues.

[MVieira]

I'm posting this for a good friend of mine at work. I've been trying to help him diagnose his problem but I have a 2nd Gen truck and I'm not very familuar with the 3rd Gen 5. 9s. Any advise or ideas here would be very much appreciated.



His truck is a 2005, 2500, 3:73 axle, 48RE trans. , stock wheels & tires, Isspro gauges, Edge Juice, and he has removed the muffler and running the CAT only.



Here is his description in his words: "When towing my 5th wheel (12,000 lbs), I have been noticing the engine temp up about 5-10 degrees. On my last trip up I-80 / 6 percent grade, my trans temp was approaching 195 degrees (Sender is in the pan and normal is 130-160 degrees). Engine water temp was 208 degrees with my Edge Juice set on stock. I removed the Edge Juice on the way back and duplicated the problem. These temps came up climbing the grades. When I was climbing the grades, the truck's boost fell to 22 lbs. and EGT's started to climb. I backed out and kept EGT's under 1300 degrees. It felt like I was down 50% power. It felt like the truck was defueling or derating. After topping the grade, the trans temp dropped to 190*, engine temp dropped to 198*, and the boost came back and so did the power. I have 98,000 trouble free miles on this truck. Always pulled these grades or any other hills with no problems or heat issues. The increase in temps and loss of power have me concerned. There are no fault codes. There is no indication of trans or converter slippage. There is a thermostat in the trans cooler lines to engine coolant heat exchanger and one in the trans oil lines to the air cooler core. Have there been problems with these ? Could it be the fan clutch ? Will this engine derate for both engine and trans running high temps ?"



Like I said, any help or ideas here would be appreciated. Thank you.

Regards, Mike.

 

[Prairie Dog]

There's nothing wrong with those temps but anytime I have a performance issue, the first thing I do is change the fuel filter no matter how many miles are on it. So far, thats fixed the only two problems I ever had.

 

[MVieira]

Prairie Dog,
He has changed the fuel and air filter. Thanks for the input though. Just a note - the higher temps have just recently surfaced along with the noticeable loss of power. It has been going on for last 2 months. He runs up from Elk Grove to Fallen Nevada (Sand Mountain) almost every other weekend. He has run these same grades many times.
Regards, Mike.

 

[Prairie Dog]

Well, so much for the easy & cheap stuff

Does he have any trouble starting it? Longer crank times?

 

[MVieira]

Prairie Dog,
Yeah, we've tried to cover the cheap & easy stuff first. Not trying to bait anyone here but both of us have backgrounds as heavy equipment mechanics at dealerships. But it is possible we might have developed tunnel vision here. So I still appreciate any ideas. We are pulling our hair out on this one. I have a 24v '02 2nd Gen, which I'm very experienced with. I do not know much about the 3rd Gen common rail 5. 9s and additional electronics. I usually only follow the 2nd Gen forums. I've done a search on the 3rd Gen 5. 9s but haven't found that smoking gun yet. I still feel the truck is defueling/derating, I'm just not sure if this higher heat issue is the loss of power cause or if it is the after effect. I will post a follow up if we get this figured out. In the mean time any ideas are still appreciated.
Thanks, Mike.

 

[MVieira]

Well, so much for the easy & cheap stuff

Does he have any trouble starting it? Longer crank times?

To answer your question, no it is starting up fine. He hasn't noticed longer crank times.