Just had 3 day 1,600 or so mile road trip with my 1996 U-270

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Just had 3 day 1,600 or so mile road trip with my 1996 U-270

June 22, 2016, 12:40:09 pm

Hello all,

Finally put my 1996 U-270 through "real world conditions" aka 1,600 mile road trip from Texas to MD going through I-40, I-81...

Here are some issues I encountered during this trip:

1. Engine My 270 has Cummins 8.3 which I believe should be plenty power-wise for my needs. On flat road, I can maintain 70 MPH easily (just Coach with bike rack in the back) and I did weight my coach and it is 27,000 lbs which leaves 3,000 lbs available as max is 30,000 lbs. But when going up the hills (esp eastern parts of Tenn and western parts of Va), it lose the momentum and the MPH drops down to like 60 or so when it is on cruise control. I see "Boost" switch on the side of the dashboard and I turned on and it seems no difference. Also when I had to turn off the cruise control due to slow truck and then when I tried to gain speed esp on hills, it feels like it has no power as it is stuck on same MPH until I go over the hill, despite dropping the gear manually (it seems does not drop the gear as it should be, so I had to do it manually but pushing the gear down button). So it seems like my coach have problem with turbo thing or maybe not enough fuel going into engine. Brett did inspection on my coach and recommend me to replace fuel line from tank to filter. Brett said that it is possible that old fuel line can suck air in and restrict the fuel flow into the engine. Other possible is clogged fuel filter (which I plan to replace anyway) but the indicators shows it is still good (i.e. about halfway mark). Any ideas on why my coach does not have much grunt?

My next road trip will be on July 18 and I will be towing my Jeep (my friend drove my Jeep with boat from Texas to MD) so I knew My coach with Jeep will be very slow up in the mountains (going from MD to Indy, then KS, then IL, then MN, then back to MD).

So I have some time to tackle the "weak" engine issues. Turbo issues, fuel line issues etc....?

2. Whenever my coach hits road bumps, my coach goes up and down couple of times which is a sign of worn shock dampers. It is yellow shock damper and not sure if it has been replaced (did not see any record of shock replacement) so it might be original one so I guess it needs replacing. Sometimes I go off bit on shoulder and my coach really sways back and forth couple of times. With new working shock damper, it should go down and up once as well side to side once, not couple of times. Let me know which shock damper should I get for my coach?

3. My steering is like maybe I say mushy or loose, not big deal, but kind of one too many steering inputs to keep it straight. Would be nice to have tighter steering like go-kart-like steering. Any ideas to improve this area?

4. Not related to road trip but my rear A/C unit is leaking into my carpeted ceiling despite my attempts to seal some areas of A/C unit so I guess I have to take off the whole A/C unit and replace the entire seal at the opening. Perhaps might as well buy new A/C unit with better drainage system and new seals that will last other 20 years or so (do the job once and forget it thing). Any recommended A/C unit for my coach?

Many thanks for replies in advance!

Jamie

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #1 – June 22, 2016, 12:54:31 pm

Jamie,

Glad you are on the road with the coach.

Boost switch just combines battery banks (for starting or charging chassis battery bank). Nothing to do with power.

And, any heavy vehicle will loose speed on grades. As a rough gauge, you should climb faster than a loaded 18 wheeler, slower than an empty one-- straight physics. I will e-mail you an excellent document by Caterpillar Corp (but applies to all engines/vehicles) so that you can set reasonable expectations.

Not unusual at that age to replace the roof A/C gasket. Not difficult or expensive. No need to replace the whole unit. While up there, DO clean both the condenser (easy) and evaporator (harder). No sealant is needed.

Brett

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #2 – June 22, 2016, 01:12:42 pm

Quote from: wolfe10 – June 22, 2016, 12:54:31 pm

As a rough gauge, you should climb faster than a loaded 18 wheeler, slower than an empty one-- straight physics.

Yup, the OP should try some of the long 6%ers we have out here. Doing 60 on a climb is a "Coach Dream" for most of us, but, we DO pass 18-wheelers! I would assume the Allison is six speed?

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #3 – June 22, 2016, 01:37:16 pm

Yes, it has the Allison 3000 series transmission.

From the document I sent to Jamie:

To maintain 55 MPH on a 6% grade with a 34,000 pound coach (closest chart weight to his actual weight) would take 402 HP AT THE REAR WHEELS. So, maybe a tricked M11 in a small light coach, but not with 300 HP (as measured at the engine).

The Cummins 8.3 300 HP at the engine would probably generate around 260 HP at the rear wheels. From the chart, 268 HP at rear wheels for 40 MPH, 6% grade, 34,000 pound coach.

Again, it is all about having reasonable expectations.

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #4 – June 22, 2016, 01:42:45 pm

Jamie, check out the following posts regarding power issues with an 8.3 Cummins mechanical

USLD Update

8.3 Cummins mechanical power issues & remedies

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #5 – June 22, 2016, 01:43:32 pm

Water temperature showing around 180's and ditto for Tranny temps too. Oil pressure looks good too.

Wish I knew the fuel flow rate going into engine...

How do we know if turbo is working good?

I guess it is time to tricking out my 8.3 next winter time as I will head up along rocky mountains during summer of 2017.

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #6 – June 22, 2016, 01:53:16 pm

Jamie,

Your 96 sounds a lot like my 96 regards power. It's a lot more like a truck than a car when going up hills. At 70 mph the engine has the ability to produce decent power, but if the speed drops off a little on a hill it quickly bogs down and just won't go any faster, so keeping the speed up as much as possible helps but with the trade off of lower mpg. The transmission has a "mode" button; with mode "on" the transmission shifts up at a lower mph and then shifts down later. Normally the mode is off with each start unless it is selected. It's possible but not likely that a former owner had the transmission reprogrammed so mode is on with each start. The transmission usually does a good job of selecting the correct gear. It's a bit different than a car regards downshifts; basically does what most truck drivers would do with a manual transmission. When going down a hill in a lower selected gear to help with braking, if the engine rpm gets high enough that the engine could be damaged, the transmission will upshift to protect the engine. If this happens it is usually a big surprise for the driver as braking suddenly decreases. At this point heavy braking is required to slow the vehicle and regain control.

Any air leaks between the turbo charger and the intake manifold will result in less power, so you may want to check that. Our coaches have all the aerodynamics of a box; I believe best mpg occurs in 5th gear at about 40 mph.

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #7 – June 22, 2016, 01:54:28 pm

Jamie,

That engine in stock form will easily move you over any mountain. More about setting reasonable expectations than thinking any heavy vehicle will maintain "car like" speeds up a grade.

From the document I sent you:

HP demand at rear wheels on 6% grade:
4,250 lb car: 53
34,000 lb RV: 402

The car-- EASY.
The RV-- NOT

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #8 – June 22, 2016, 02:24:08 pm

Let's not forget, if we can't be patient enough to pull 6+ grades at 45 (normal for us with all gauges showing perfect), all our engines can be "hot rodded". Drawback? Install a boost gauge and pyrometer where you can DRIVE BY IT, otherwise, you,ll blow the turbo first, and then the engine. So much for getting to the Park today.

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #9 – June 22, 2016, 02:38:12 pm

Jaime,

I see you are full-timing. Your perception of performance might be colored by what you have driven in the past. If you were used to driving a real Hot Rod, then the Foretravel may seem tame by comparison. You will get accustomed to the slower pace going up hills - it actually becomes quite relaxing and enjoyable, once you adjust your expectations. Gives you more time to enjoy the mountain scenery!

If you want to achieve optimum performance from your 8.3, first be sure you have covered the basics. Make sure the filters (fuel, oil and air) are fresh. Then, you might want to take a look at the fuel system. I went through our coach not long after we bought it, and replaced/upgraded some of the fuel system components. You may be interested in this thread:

Fuel System Science Project

The mechanical C8.3 is one of the most respected and reliable diesels ever produced. If you treat it right, it will give you many years of trouble-free service. You may not win the race to the top of the hill, but you will get there!

Go to this site, and register for the "Limited Owner's Plan". You will then have access to MUCH interesting and helpful information:

Cummins QuickServe Online

Enroll in the Power Club, and you can save money on parts and service at Cummins Service Centers:

http://www.cumminspowerclub.com/index.jsp

PS: Please edit your signature. You have a Cummins 8.3...not a Cummings 8.3. Show Pride in your Ride!

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #10 – June 22, 2016, 03:01:05 pm

For those considering aftermarket additions to raise HP, a couple of points:

Added HP adds to heat load-- you will need to confirm that your cooling system is OVERsized enough to handle the extra load.

Engine longevity can be an issue if producing more than spec HP.

Consider the FACTS of what it will do for you.

Again from the Caterpillar Corp Document that I sent Jamie:

34,000 pound coach, 6% grade, HP REQUIREMENT AT THE REAR WHEEL:
40 MPH: 268
45 MPH: 310
50 MPH: 354

Yes, by spending some money, you could probably go 5 MPH faster up those 6% grades. Really doubt you could get to 10 MPH faster without spending a huge sum and really compromising reliability.

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #11 – June 22, 2016, 03:30:10 pm

Old timers (me) will tell you, "ignore the speedometer, drive by your gauges." Our Allison will shift multiple times on a climb, never had it shift below 4th, unless some bread truck in front made a lane change dicey.

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #12 – June 22, 2016, 04:25:12 pm

Quote from: Chuck & Jeannie – June 22, 2016, 02:38:12 pm

If you go to this site, and register your engine, you will have access to MUCH interesting and helpful information:

Cummins QuickServe Online

Chuck.

I tried it, but they wanted a whole lot of money to create an account.

Did I miss the secret code?

Thanks,

Trent

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #13 – June 22, 2016, 06:44:56 pm

This old guy rolls around at 59-61 mph 'driving the gauges' I did remember from my days under the hood that this wrench I worked around said that the most effective way to warm a Cummins was to retard the cam. This guy could pull a 13 speed gearbox, do a clutch job and have it all back together in a morning........by himself

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #14 – June 22, 2016, 08:26:51 pm

Subject to the checks posted here the power seems to match other known good condition similar coaches.

The oem shocks were bilsteins and budget permitting have been replaced/upgraded by a set of koni FSD shocks by many owners.

Taken me four careful years of work the address similar ride and handling issues.

A vast improvement of the dampening was the koni installation.

Second was to replace any worn parts in the front steering suspension.

The mechanical fuel injection BOSCH fuel pump was modifiable with a screw driver to put out more fuel and that's what I would have done before my first drive.

Third and most important in my case was to have the front wheel bearings slightly preloaded.

Current normal for legal reasons is slightly loose as that's measureable.

Then we can discuss how different tires themselves alter the ride and steering and noise.

All solvable...

Tires, shocks, steering components, bearing adjustment and alignment maybe the steps needed.

I notice you mention the power first.

Power to weight ratio on these is a much more important factor in the hills.

If you are a left lane guy the 8.3 will take some adjustment.

No replacement for more displacement and power in a Rv.

Good coach. Worth tinkering with maybe for a bit more power..

The mechanical injection 8.3's can be improved quite a bit.

Probably not readily available anymore but look at Gale banks web site as they used to mod these.

Subject to the heating and trans limitations issues mentioned I have driven these after mods and the difference was major.

But then you get to watch the gauges.

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #15 – June 22, 2016, 08:32:49 pm

Quote from: TulsaTrent – June 22, 2016, 04:25:12 pm

I tried it, but they wanted a whole lot of money to create an account.

Trent, (I edited my post above for clarity.)

You were probably looking at the "Unlimited Service Plan". That is for big companies and corporations with a large fleet of trucks. What you want is the "Limited Owner's Plan" - the one on the right on the page below. It's free, which is a great price for what you get!

Cummins QuickServe Online

All you will need is the engine serial number, which you will find on the data plate affixed to the edge of the sheet metal cover right below the a/c compressor (at least on my engine). In the photo, the data plate is above and to the right of the oil fill hole...the shiny black area directly in front of the injection pump.

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #16 – June 22, 2016, 09:24:26 pm

Quote from: wolfe10 – June 22, 2016, 03:01:05 pm

For those considering aftermarket additions to raise HP, a couple of points:

Added HP adds to heat load-- you will need to confirm that your cooling system is OVERsized enough to handle the extra load.

Engine longevity can be an issue if producing more than spec HP.

Consider the FACTS of what it will do for you.

Again from the Caterpillar Corp Document that I sent Jamie:

34,000 pound coach, 6% grade, HP REQUIREMENT AT THE REAR WHEEL:
40 MPH: 268
45 MPH: 310
50 MPH: 354

Yes, by spending some money, you could probably go 5 MPH faster up those 6% grades. Really doubt you could get to 10 MPH faster without spending a huge sum and really compromising reliability.

354hp @ the wheels is 450+ @ the crank......Dave M I'm sure you can relate..

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #17 – June 23, 2016, 01:04:00 am

There is much to learn and enjoy with a FT. We have had our 96 U270 for 15 years. Full-timed for nearly 8 of those years. Soon, during the first year, we gave up 500+ miles-a-day scheduling. Nowadays, 300 miles is a LONG day for us, which may include: a leisurely lunch, and a bit of afternoon delight, and possibly a nap.

We greatly appreciated the effect of weight on road performance. (Balanced loading is something you will learn about.) With minimal planning, we easily got smart about full fuel, and fresh water, and food stored in every cabinet, and so on. Having large capacity tanks when needed is a great feature of the FT. We do not normally need all that. (Hint: I would not have everything full and then go over Wolf Creek Pass....)

I do NOT have any FUEL FILTER indicators on my 96/270. Could you be referring to the AIR Filter restriction gauge?

One of the first things I "repaired" was lining the engine compartment and covering the hot parts of the engine. (Normal HD/Lowe's foam insulation board made it a one man job using fender washers/screws, a sharp knife from the kitchen, and a campsite table. Wrapped the turbo and exhaust line to the muffler in 2" wide flexible fiberglass from an online "Racing Kit" package.)

After converting to OAT coolant, I found that my engine normally operated at 170. I try to limit my climbing temp to a conservative 180. (Cruise at 63-5 on level gives 170; early downshifting and not pressing the throttle much usually gives me 180 climbing. Three weeks ago, going over Wolf Creek I got to 185 and 3rd gear in spots. Of course it was hot outside. It had been 100 degrees in Chinle that week.) The temp gauges are the focus being mentioned by other owners. Coolant temp while climbing. Trans temp while descending. Be aware that the transmission gauge may under-indicate the actual trans fluid temp by 50 to 100 degrees and has an upper limit.

Of course, alignment may affect steerage. And tire condition. So does ride height. (However, do a bit of study before messing with ride height.) Our coach has the original shocks. They are still okay for us. We have gone many miles on unpaved roads. (Chaco NP, John Jarvie HP, Alaska.) We live on the side of a mountain, on a road UPS refuses to deliver packages. (I call it my two-beer road.)

I grew up in Kansas. Be ready for those mountains and mesas there on your next trip.

Read everything Barry and Cindy, Brett, and Neale have to offer....

Andy1

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #18 – June 23, 2016, 06:48:48 am

Your trip seems familiar to mine a few months ago. The ride and handling on our 270 was greatly improved when I replaced the original Bilsteins with Koni FSDs. These can be purchased on line in the 155 or so range.

The transmission is smarter than I am. It took a bit to realize what I had and now I love it. Still unclear on the temp range but changed to Transynd.

Coming from a 5.9 Ram pulling 10,000, the climb rate was disappointing but the truck was goosed by Banks to 425 plus. My trip west in the coach I would drop to 50 on the worst interstate grades. As a retired guy, I don't have to be anywhere faster.

I do not have a fuel filter gauge and I think you are referencing air filter. I did add a Parker purge system.

So far, I have had only one unexpected failure. The steering box.

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #19 – June 27, 2016, 09:41:26 pm

I do have fuel filter indicator on my '96 270, I guess PO added it.

What is the part # for Koni FSDs?

I thought my Allison tranny should downshift sooner, I guess I need to read the manual and understand the tranny controls.

Agreed to drive by the gauge, I kept looking at the temps and make sure they are in comfy range.

Any recommended gauges to add besides those stock ones? Like turbo boost guage?

`Thanks!

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #20 – June 27, 2016, 10:05:06 pm

Quote from: jclark93 – June 27, 2016, 09:41:26 pm

I do have fuel filter indicator on my '96 270, I guess PO added it.

What is the part # for Koni FSDs?

I thought my Allison tranny should downshift sooner, I guess I need to read the manual and understand the tranny controls.

Agreed to drive by the gauge, I kept looking at the temps and make sure they are in comfy range.

Any recommended gauges to add besides those stock ones? Like turbo boost guage?

`Thanks!

If you don't mess with the horsepower you don't need a boost gauge.

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #21 – June 27, 2016, 11:35:40 pm

Boost gauge can be indicative of problems such as boot come loose or exhaust manifold leaks. Pyrometer can be helpful also.

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #22 – June 27, 2016, 11:54:23 pm

We had the banks kit on our 95 280. It was truly impressive. Exhaust temp was no joke! Keep speed /momentum by rolling on throttle when you see climb coming . You can always down shift in advance of dropping below peak torque. I always kept our 8.3 at or above 2000 rpm on hard climbs .

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #23 – June 28, 2016, 09:06:27 am

Quote from: jclark93 – June 27, 2016, 09:41:26 pm

I thought my Allison tranny should downshift sooner, I guess I need to read the manual and understand the tranny controls.

Old threads - good discussion of Allison behavior:

Allison 'ECON' mode

Allison Mode Question, 99' U270

Re: Just had 3 day 1,600 or so mile road trip with my 1996 U-270

Reply #24 – June 28, 2016, 10:19:56 am

Defiantly more control and not going to have those up and down motions

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