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mhs4771 · 01-02-2013, 05:58 PM

Change both Fuel Filter and Air Filter. Turbo Diesels need plenty of air and a plugged or partly plugged Air Filter will limit power as will a plugged Fuel filter. I was pulling a 14K Montana with a 2005 3500 Dually and could generally maintain 60 to 65 on US 15 across PA

KD4UPL · 01-02-2013, 06:55 PM

Does the truck have stock size tires or have they been replaced with something larger. Larger tires will adversely effect the towing performance.
I suspect the trailer is heavier than you think (they usually are). If I remember correctly that is pretty much the maximum tow rating of that truck.
I don't know how steep the grades are that you're pulling but it is quite normal to slow down going up hill. You can't beat physics. My '05 Dmax can only maintain about 55 up some grades on 64 in VA and WV towing about 15,000 pounds. It is bone stock in the drivetrain department.
I just hold the pedal to the floor and let the engine and Allison do their thing. I don't have gauges. I figure GM built it to last. 160,000 hard working miles and nary a problem.

gtmatt · 01-03-2013, 06:53 AM

The truck has stock tires as far as I know, though I don't know what size originally came on it -- it's not jacked up or anything. I do not have a pyrometer. The engine is an LB7, but it was replaced (entirely) a few years ago.

I have not weighed the trailer yet, but it didn't have a whole lot in it as I was not towing it to use it for anything at the time. So I just took the dry weight and added ~1200 or so lbs. to adjust for the stuff I know the previous owner added, some cargo, and some water weight in the tanks. I do plan on weighing it soon as I'm going to start actually using it.

I did not use cruise control as I didn't know if I should while towing. But it sounds like that is fine. It might help even out my speeds, I suppose.

I do not know the "normal" RPMs. I will pay attention to that next time I'm on the highway. I did try using it without tow/haul mode briefly and that hill performance seemed worse.

Tow capacity is 14700 for the fifth wheel. I think the rear axle ratio is 3.73. I do not know the toque and horsepower ratings.

Sounds like replacing the fuel filter should be on the list. The air intake is an aFe aftermarket setup, and I know it is dirty and needs cleaning. I'll try those two things and weigh the trailer once it's loaded and go from there, I guess.

Thanks for the input so far.

Oscar Mike · 01-03-2013, 06:58 AM

Gravity...what can you say...

JohnBoyToo · 01-03-2013, 07:17 AM

Oh, ok,
so this is not the original engine... this is a replaced engine....
sounds like your deezle needs a tuneup ...

new plugs, rotor, etc....

I know, I know, just kidding

but would guess it is engine related - maybe join a deezle club and go spend $45 to get on a dyno to see how it performs... good luck

fvstringpicker · 01-03-2013, 09:25 AM

Go here GT for research:
Duramax First Generation: 2001-2004 (LB7) - Diesel Place : Chevrolet and GMC Diesel Truck Forums

And keep your RPMs about 1600

Fred1609 · 01-03-2013, 09:35 AM

Talking about a pyrometer, We spoke to Ford after replacing two turbos under warranty and asked if we could put a pyrometer for the turbo. The gas told us that this might void the extended warranty. Unbelievable. So I guess for the next two years ford can replace at least one more turbo.

gtmatt · 01-03-2013, 07:13 PM

Had the codes checked, it is showing P1093. Everything I'm finding says replace the fuel filter as the first step.

KSCRUDE · 01-03-2013, 08:22 PM

Any air filter that you have to wash is pure junk and will dust your engine. Like K&N and other oil soaked Cotten gauze filters. We change air filters at every 5 k oil change on pickups driven in the oilfields. New air filters every time. We don't waste time washing a dirty cotten rag filter and dousing it with oil and reusing it. New paper oem style filters. On gas engines the oil on the K&N style filters will make the MAS malfunction. And even if you are a K&N fan who wants to wash it every 5K miles? Keep running that air filter and you may be replacing another engine. JMHO.

jaycocamprs · 01-03-2013, 08:35 PM

Fuel filter & air filter. There realy aeren't any grades on Georgia Interstates that you should have that kind of trouble pullling.

fvstringpicker · 01-03-2013, 09:29 PM

Quote:

Originally Posted by gtmatt

Had the codes checked, it is showing P1093. Everything I'm finding says replace the fuel filter as the first step.

That's a good first step. Put a Delco filter on it and don't use anything else. Another problem, if your showing that code, may be a leaking down injector. If I'm not mistaken, P1093 indicates low rail pressure.

fvstringpicker · 01-03-2013, 09:36 PM

Quote:

Originally Posted by jaycocamprs

Fuel filter & air filter. There realy aeren't any grades on Georgia Interstates that you should have that kind of trouble pullling.

Not exactly in Georgia, but on I24 north of Chattanooga, I could tell I had a load behind me.

http://www.youtube.com/watch?v=aNgeu7i6eOk

jaycocamprs · 01-04-2013, 03:59 PM

Quote:

Originally Posted by fvstringpicker

Not exactly in Georgia, but on I24 north of Chattanooga, I could tell I had a load behind me.

That would be "West" of Chattanooga. But your right Mounteagle will pull you down. But our LLY will hold 55 in 4'th just fine, but we may be a little lighter than the OP. The hill on I-75 about MM 18 is steeper than Mounteagle, but it's short. Also coming east out of downtown Chattanooga up Missionary Ridge is a pull.

fvstringpicker · 01-04-2013, 09:09 PM

When Im going to Kentucky from middle Georgia, everything seems north to me Jayco.

. Whats really unnerving on that stretch of I 24 is the constant smell of brakes heating up on the big rigs that are descending the hill; especially when eastbound toward Chattanooga. I try keep them from getting behind me on the decent.