Calling 2000 thru 2002-38' dutch star owners

[mikee409]

I'm asking that only owners of these year models and engine combinations respond to this post please. Needed, 2000 thru 2002 38' Dutch Stars with a 330 hp Cummins engine. I need to know what your average fuel mileage is, please.
I'm trying to figure out if I have an issue with my engine. Here's the story. The last 3 trips we have made to the same destination not towing the jeep have resulted in 6.7 mpg. doesn't seem to matter if I drive 55mph or 65 mph. Last year we made a 2500 mile trip and averaged 8.5 mpg towing a jeep. The only thing that's changed is I had the exhaust gasket leak fixed.
Being some what familiar with engine performance I think the engine was breathing better with the exhaust leak maybe?
If the rest of you brethren with the same rigs are averaging about the same as me I will just leave it at that but....... if Ya'll are doing better I will need to investigate further for issues. Please, just owners of my type rig respond so I will have an apples to apples comparison.
All help is greatly appreciated, Thanks in advance, Mike

[Rotten-Red]

Mike, I have a 38' 2000DSDP with the 330 Cummins, same as you. I tow a 07 Saturn Vue which weighs in at 4,000#. Total combined weigh is 32,000#. Every trip I've taken always comes out with an average of 7.25 MPG. @ 60MPH. I'm running a straight thru muffler. Also have the Banks kit, but I can't see where that has helped fuel mileage.

Fixing gaskets on exhaust manifold shouldn't affect your mileage to that extent. You might check your exhaust brake butterfly to make sure it is completely open, not stuck in a partially closed position. Other than that the muffler is the only restriction on the exhaust.

If your power seems to be normal and your not getting black smoke from the exhaust the turbo is probably ok.

[Mr_D]

We have a 4090 on Spartan with Banks kit (stock exhaust). Get about the same as Rotten-Red although maybe a little higher at 7.5. Banks didn't seem to make any difference in mileage.
Just validating what Rotten-Red said as the extra 2' and weight doesn't mean much.

[Ramets]

6.7mpg seems a little low. When was the last time you changed the air filter? The exhaust break suggestion is a good one. No black smoke? The last 3 trips you mention...what's the distance one way? Any steep grades? I always get my best mileage on long trips. The best I've ever done was a 9,000 mi. trip to Alaska. I got 9.75mpg, but have never been close to that since. Also it doesn't seem to matter whether I'm towing or not, my mpg seems to be pretty much the same. Wierd?

[tcfamy]

We have the 2001 3852 with the 330 ISC. For years we averaged 7.25 overall with a toad or trailer. add a couple of tenth mpg when we travelled without a tow. Two years ago have the cooling fan changed to multi speed vs the original always on one speed fan and we now average 7.9 towing and 8.2 not towing. I also think overall the 6.7 is a bit low, although I have been in the sixes fighting a strong headwind. There are sooo many things like low tire pressure, restricted exhaust, etc that could easily drop you down I would not know where to start. But if the engine work is the defining point of the mileage drop, I would look at everything the service guy touched. He may have unplugged a sensor and not plugged it back in?? I think checking the exhaust brake is a very important. Easy to get bound up if disturbed or not lubricated. Best of luck on the adventure!

[mikee409]

@ Ramets, It was all flat land except for 3 bridges we crossed. The round trip was 88 miles. It's 40 min. to the beach from our home. We like to get away for the weekend and it's close. The filter was replaced last year in June and the indicator shows no restriction to be worried about. @ Mr D, We have gotten better mpg some times but here lately it seems to have fallen off for no apparent reason. @ Rotten-Red , seems like after the exh. gasket repair/ manifold replacement is when I really noticed the change. The rig still runs smooth and I don't see evidence of black soot or smoke. Was thinking of the exh. brake but it seems to work properly when activated. Was considering trying a less restrictive muffler or making a straight pipe to just try and see what the results would be before buying another muffler. Had a 79 Ford p/u one time that got 8 mpg. Adding headers with an alum. intake & carb. increased it to 12mpg! I don't see that happening with the diesel and the mods that can be done to it. May try another air filter, not sure of the flow rate the replacement one was or if it was the same part number. The freightliner dealer that did service on the rig when I 1st got it was a joke. And yes I know I will get better mpg on a straight run down the hwy. but still feel somethings amiss?
Thanks to all for the reply's and suggestions . By the way I have 79000 miles on the motor.
Mike

[Rotten-Red]

Mike, IMHO, I wouldn't spend to much time, effort, and money on this until you run on a much longer trip. An 88 mile trip really isn't a good mileage test. Even refueling the tank has variables. It's almost impossible that the pump will shut off at the exact same point each time. On an 88 mile trip just adding a little more fuel when refueling can change your mpg.

As for your air filter, it's probably fine if your restriction gauge doesn't show it needs changing. My restriction gauge reads 15 with a new filter.

I have 94,000 on mine.

[mikee409]

@ Rotten Red, Last year we drove 2500 miles to the grand canyon with the blown exh. gasket. Average was 8.5 towing a jeep Cherokee. Were making a big loop to Mt. Rushmore , Devils tower, Arches nat. park/ monument back down thru NM back into Texas catching Palo Duro canyon state park & then home on the TX. LA. border near the coast. Any increase will help my bottom line. I can afford to drive the RV but I'd rather spend the extra money on other things fun to do. The oil and gas companies have plenty of money, we need to spread the money around to the smaller business owners, mom and pop operations and tourist traps. I hope these lower diesel prices hold thru our trip, and way beyond !
Mike

[mikee409]

Hey, the exhaust brake wasn't even connected up at the dash when I got the rig. I was testing things when I 1st got it home back in June and couldn't feel any difference with the dash switch on or off. Started investigating and found the wires under the dash were unplugged from the switch. Connected them to the switch and it worked fine? Wonder what was up with that. I'll still check it again to see if its open all the way. I used it this past weekend and it's doing it's job. Something has changed since the road trip last summer, I just haven't figured it out yet. Hope it's an easy fix
Mike

["007"]

Unless there is a locking tab on plug vibration traveling down the road can possibly loosen the plug from its spade clips connection.