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Mileage?
06-22-2017, 17:41
Post: #1
Mileage?
I think most S-60 engines pushing a 50,000 pound coach down the road will get somewhere in the 6 miles per gallon range. Some may get as high as 6.8 MPG and some will barely get 6.0 MPG on average.

From the time I bought my coach, it struggled to maintain 6 MPG and sometimes dropping to as low as 5.8 MPG. I was not happy with that low mileage and set about trying to figure out how to get better mileage.

By shutting off the Prevost dash air and instead running 2 roof air conditioning units off the inverters and only turning on the Jake brake in congested and high traffic areas, I have been able to improve my fuel mileage to 7.1 MPG.

I travel at 63 to 65 mph although it didn't make much difference in fuel mileage no matter if I ran slower or faster. I'm guessing that the Prevost dash air conditioner compressor must rob the engine of enough horsepower to effect the mileage at maybe .5 mpg and the Jake braking the coach each time the accelerator is lifted effectively lowered the fuel mileage another .5 mpg.
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06-22-2017, 20:12
Post: #2
RE: Mileage?
I get 6.8 to 7.5 mpg from my 03 (chassis year) H-3 double slude and 98 (chassis year) XL. Both were non-EGR engines.

I drive 63-67 mph, almost always use cruise control and Jake when on the interstate and major highways. I had the transmissionsame programmed not to attempt a downshift to 4th gear when the Jake activates.

Most of my driving is on the east coast with few hills. I would guess my mix of interstate and secondary road driving to be 70% interstate.

I always tow a 4,500 pound Ford Explorer.

I did get about a half gallon improvement after having my fuel injectors replaced. FWIW, I understand EGR engines get closer to 6 mpg than 7.
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06-22-2017, 22:49 (This post was last modified: 06-22-2017 22:50 by cmillsap.)
Post: #3
RE: Mileage?
I very seldom use an additive such as Lucas Diesel Clean anymore. I used to buy it at Walmart and treat every 3rd tank with it but it didn't seem to make much difference in engine performance.

There are a lot of products on the market that claim to restore injectors rather than having to replace them. Here's one that claims documentation to back up their product's capabilities.

http://www.hotshotsecret.com/wp-content/...de2016.pdf

Maybe I'll give the Stiction Eliminator & Diesel Extreme a shot to see if it will help my mileage.


Chuck & Tela Millsap
Arizona
2003 Marathon XLII S/S
2000 Wanderlodge LXi S/S
2004 Wanderlodge M380 D/S
2000 Wanderlodge LXi N
/S
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06-23-2017, 07:50
Post: #4
RE: Mileage?
I had a leaking injector. I don't think any injector cleaner was going to fix that. I suppose my fuel mileage improvement didn't come from repairing the leak but maybe from dirty injectors.
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06-23-2017, 11:40 (This post was last modified: 06-23-2017 11:59 by travelite.)
Post: #5
RE: Mileage?
Chuck, way to go on finding the cause of your reduced MPGs. I know you've been wondering about that for quite some time. I never run my dash air. I have a cruiesair mounted above the captain's seat and dedicated to the captain. I stay nice and cool. The cruisair even has vents which can be directed at the windshield to defog it.

CC_Guy, I had a leaky injector on my 2002 S60 equipped Wanderodge LXi. I found it when I replaced my CAC and exhaust manifold. Found dampness around one of the exhaust valve guides. It does happen. I made a big mental leap and blamed it on low sulfur fuels, but there's not telling for certain. I had Clarke Power Services in Charlotte NC pull the head and at their recommendation press in all new copper injector sleeves. They replaced the injector and added the auxiliary O-rings for double protection as shown in the attached doc. I guess they figured if the injector was leaking there might be some microscopic movement of the tube. Not to cause panic, but it pays to be careful with this stuff; leaky tubes and seals can let coolant seep past into the cylinders:


.pdf  S60_Injector_Tube_S60.pdf (Size: 41.16 KB / Downloads: 5)

david brady,
'02 Wanderlodge LXi 'Smokey' (Sold),
'04 Prevost H3 Vantare 'SpongeBob'

"there is no perfect forum there are only perfect forums"
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06-23-2017, 17:12
Post: #6
RE: Mileage?
Just a FYI. My injector problem didn't affect a thing until it affected everything. All of a sudden I couldn't get past 3/4 boost without an almost total loss of power. An o ring seating the injector tip would allow combustion air to leak back up through the injector. This then resulted in air being pushed down stream of the bad injector. This air resulted in fuel starvation for the down stream injectors.

The troubleshooting was a costly nightmare. I finally had to step in to help figure a way to perform a definitive test. If the shop doesn't have a dyno or a doesn't have a dyno that is far enough a way from the wall, this is not easy to troubleshoot.
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06-24-2017, 11:10
Post: #7
RE: Mileage?
So how did you ever figure this out? Did you see air bubbles in the fuel line or fuel line pressure spikes?

david brady,
'02 Wanderlodge LXi 'Smokey' (Sold),
'04 Prevost H3 Vantare 'SpongeBob'

"there is no perfect forum there are only perfect forums"
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06-24-2017, 21:45
Post: #8
RE: Mileage?
David,

Initially, a following friend said my coach would expel puffs of smoke. Quickly after that the problem was obvious. If I pushed the engine beyond 3/4 boost the engine would immediately lose power and seem to come close to stalling. If this happened in a hilly area my coach would havery needed a tow.
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