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Topic: Dash gauges versus silver leaf and other questions... (Read 961 times) previous topic - next topic

Dash gauges versus silver leaf and other questions...

Just returned from a 2,500 mile drive.  Noticed that the dash gauges do not match the silverleaf

No  wonder others have questioned my higher temps I mentioned I have and do run up grades.

Dash gauge says 215 on the engine temp but the silverleaf says 199. 

I understand there are different sending units for the two systems. 

Why that much difference?  Normal?  Or does the dash gauge sending unit need a retightening maybe for a better electrical  contact?

Dash trans gauge is the opposite.  Low indicator.  Sliver leaf higher.

Purposely ran our coach down the grapevine on interstate 5 south from Lebel with the retarder on the second or third position and on cruise at 60 mph just to check the retarders operation and watch what the gauges say.

Silverleaf showed 250 from the trans when the warning light and buzzer came on.  Two miles later as the trans cooled off to 240 both went off.

Not retarder temp as my current setup only shows "trans temp"

Have not got into the loom to find the retarder temp wire I understand is there yet.

Wonder how the trans and retarder temps are related?

Floored fourth up the grade at 36,000 pounds combined netted 50 mph at the slowest up the grapevine from the Bakersfield side.

Have no real idea if that's good or not?

7.5 mpg with lots of weasel trail during the trip from LA to the Columbia gorge and back. 

20 gallons for aqua hot and gen. 

Dash speedo is 4% high.  How to adjust it?

Silverleaf and GPS matched.  Speedo high.

Interesting thing I think I noticed.  My 110 volt aqua hot works on the inverter if no gen or shoreline power present.

Same as my icemaker and freezer compressor if both on.

Ran my house batteries down almost 50% overnight with both on in 40 degree overnight temps at 6,000 feet.

-320 amp hours by morning.

By accident I left both switches on the Aqua hot on. 

Not sure if it's intentional but another Foretravel backup as it is.

In an emergency and the diesel side off or out  the batteries can run the aqua hot overnight in fairly cool weather no problem.

Might use this on purpose versus run the diesel side.  Not that much alternator/solar time to recharge 150 amp hours per day if moving in a day or two. 

Quieter.  No smell downwind.  Less gen noise.

Is mine wired differently?

Lastly has anyone noticed large jumps in the silverleaf RMPG?  Like from 8 to 9 plus at times.  Same speed.  Flat ground.

Mine does it fairly regularly.  Sometimes over 10mpg?

Like a large engine load is on and off that should not be there.

I have an idea what is happening but wonder if anyone else has seen this?

Thanks for your help.

Bob

Re: Dash gauges versus silver leaf and other questions...

Reply #1 –
My AH is not wired for the inverter.  I wonder if you were just using residual heat from the engine. 40 degrees is not that cold and my AH will still give hot water after a night parked. 
There is two settings for retarder temp, one at the sump and one at the retarder itself.  One gas a 250 max the other 300.  Tire size is probably your difference and it is interesting that it is a lower temp too. Only climbing I 70 in the hot of summer have I hit 212.

Re: Dash gauges versus silver leaf and other questions...

Reply #2 –
AH light will come on if you flip the 110 switch on, relay will clunk but the power to that circuit only comes from shoreline or generator.  It doesn't take the AH to come up to as much as it is going to off engine heat.  That is plenty to heat zone 1 (LR) over night at 64° when it is 40° outside.

Electric and diesel at the same time is ok but the electric doesn't (shouldn't) work if no landline or gen.  If yours is wired to run on the inverter it is miswired or someone changed it. i think in mine it is a 1200 watt element.  That would be a 110 amp draw at least accounting for inefficiencies.  Batteries won't last long at that load.

Shouldn't your cruise control disengage if you have the retarder switch on on pull the stick back a ways?  They shouldn't both work at the same time.  Just like stepping on the brakes, cc disengages.

On you coach I'm not sure where VMSpc gets data. On mine (2001) it all comes from the data bus from the ECM.  I don't know for sure but would be surprised if there were different sensors for the dash coolant temp and the coolant temp reported by VMSpc.
The engine selection tells VMSpc how to interpret the signals.  You can put in adjustments to all,of the guages in VSMpc to get them to read anything you want or to match gauges or some other measurement.  My GPS and VMSpc are always the same for speed.  If VMSpc is reporting total fuel at one fuel fill to the total fuel at the next fuel fill and I fill at both places in the same way and I have not used gen or AH the fuel I add is within a % or so.  It says I need 100 gallons, I put in 99-101. Very consistant.  How you fill (whatbdo you call full?) can vary this amount a lot.  Just 1/10" in your tank is about a gallon.

RMPG is a moving average that updates avery minute or two.  The time span of the average is many minutes, maybe as much as 10.  I haven't seen a spec on that.  As such it should change slowly as conditions change. Wind, hills, speed, load, your foot and many other things come into play.  I get worst mpg at freeway speeds on up and down stuff with lots of head or cross wind. I drove from Denver to HWH in Iowa, over 700 miles, and averaged 11.7 mpg at 65 mph.  Excellent tail wind.  RMPG was pretty much in line with that. 

That is what I have seen.

Re: Dash gauges versus silver leaf and other questions...

Reply #3 –
Thanks roger.

My retarder works on cruise and the brake lights turn on when it engages.

Others have reported two temp senders on my m11 celect plus.  And that the Vpms and the gauge use a different sensor.

Would be a lot of battery to run a heating element. Will test it this morning.

But my normal overnight use was 220 amp hours with the refer compressor and icemaker on. 

Having the 110 switch on it went to 330. 

Plus the operating noise was different.  Quieter.  Pump only working.  As the electric element is set for 175 degrees and the diesel for 185 turn on if it's not that cold the diesel never comes on.

When I saw that I had left the switch on overnight for the 110 volt I turned it off and the diesel burner and its louder noise instantly came on. 

So the power draw and lack of noise which I am sensitive to and the lighting of the diesel burner when I switched off the 110 is why I think the element is wired on mine through the inverter with no shore power or gen.

More testing is coming.  Still learning after 3 1/2 year of ownership.

Does your RMPG during a non hot flat run with minor condition changes suddenly jump up 1 or more mpg?

The two major draws on the motor other than the rear wheels and a/c are the alternator and the hydraulic engine fans.

After my house and engine batteries were fully charged I was still getting the fluxuations.

Motor feels soft to me as it revs up.

Bad exhaust muffler(restrictive?), dirty air filter? I have a new Donaldson blue woven replacement not installed yet that shows on Pittsburg powers web site as a performance addition on my m11 to test. Or the alternator is drawing that much power which I doubt or the sundstrand hydraulic cooling fan control is running the fan on high speed at low temps.

I wonder if Foretravel speced the control to run at lower temps than the units I have  speced.

Knowing how most Rv owners get very worried if the engine temp goes up ever I need to find out if there are alternate temp range cooling fan controls available.

The ones I have seen run low speed to 195 then ramp the speed up to max at 210.

My thoughts were either mine runs full at low temps as part of the design if it's a lower temp unit or that it bad and sticks on high when the fan is not that needed or both or none of the above.

Plus a need to have the alternator checked itself.

One thing I have learned long ago running Rv stores is that every single system in a long used old coach is to be considered bad until proven otherwise.

As an example I had a noise from under neath the middle of the coach on the paasenger side while driving.

Finally found that the chest freezers sliding latch to lock the trays engagement end was bent in and/or worn at an angle and under load it moved up and allowed the freezer to slide out and hit the compartment doors inner surface.

Rub marks on the painted handle and matching marks on the doors inner plastic cover....

Stupid worn latch...

I actually like the aqua hot able to work on the inverter.  Another backup.  Or save diesel fuel.

Thanks for your info.  Keep it coming

Re: Dash gauges versus silver leaf and other questions...

Reply #4 –
My RMPG does not change suddenly.  A 5 minute climb and I don't see much change for a while.
My dash coolant and transmission temp gauge and VMWpc are consistent ~ 175 normal. Really hot days maybe 185-190. Transmission is normally about 7 degrees more, retard temp another degree or two.  Almost never let my retard temp go much over 235.  Down shifting gets better cooling.

I am quite sure my AH 120v heater does not run on the inverter.  Yours may be wired differently.  That kind of sustained load is huge.  It is on/off kind of thing at 1200 watts.  120 amp draw from 12 v through the inverter to 120 v at least.  Ambient to normal operating temp on electric is 2+ hours. 

Re: Dash gauges versus silver leaf and other questions...

Reply #5 –
On our 1995 U320 the dash transmission gauge appears to read the retarder output, since it climbs quite rapidly when the retarder is used. The VMSpc appears to read transmission sump temperature, since it climbs very slowly when the retarder is used.

Re: Dash gauges versus silver leaf and other questions...

Reply #6 –
My transmission analog dash gauge changes much more slowly then the Silverleaf during retarder use. I believe this is because the dash gauge is reading sump pan temperature while the Silver leaf is reading pump output temperature (fluid going to radiator to be cooled. The temperature to watch most closely when retarding is the output temperature because fluid will be damaged and turn dark at a certain temperature. If fluid is dark, the viscosity has changed and it will heat faster and eventually cause damage to transmission. Synthetic fluid will tolerate higher temperatures than standard fluid. I believe it is foolish to run non-synthetic fluid with a retarder.

I watch my GPS to determine the speed and have not noticed a discrepancy with the analog dash speedo, or the Silverleaf.

My 1996 U320 climbs the Bakersfield side of the Grapevine at 48mph, 4th, 1700rpm, towing 3000# car, so 35000 pound combined. I check at weigh scale and was 31,900 pounds when fully loaded and going to California for the winter.

Regarding Rolling MPG from the Silverleaf. The number displayed can be modified by changing the time/distance parameter. It sometimes displays 99.9mpg and sometimes 1.5mpg and can vary quickly. Decreasing time/distance parameter shows the effect of changes more quickly. 

Re: Dash gauges versus silver leaf and other questions...

Reply #7 –
Hi Roger

Do you reset your VMSPC tank gauge upon refill to 194 gal (size of tank) ? or something else?

Re: Dash gauges versus silver leaf and other questions...

Reply #8 –
If I fill it, yes.  If not I just add to the fuel level.  This is a rough estimate to show miles to empty.  There is another gauge, total fuel.  This just shows how much fuels has gone into the engine.  If at one fill it reads 1500 and at the next it reads 1600 and I fill consistently I will add very close to 100 gallons.  The difference in miles at the first stop and miles at the second stop and the difference in fuel is a good way to calculate miles per gallon.

VMSpc use in general.

Here is what I think. VMSpc is a great tool for watching your engine, transmission and battery parameters.  Temps might be off a few degrees, miles might not be exact, fuel use might not be exact but that is OK.  Like a tire pressure monitor what you are looking for are changes and readings out of the ordinary.  If your engine reads 173° most of the time for engine coolant temp and maybe 185° under big loads then anything outside of that range you probably want to pay attention to.  It is what you normally see that is important.  172 or 175 are both normal.  You dash gauge probably doesn't read the correct temp either and probably is only accurate to 3-5% anyway.

So set it up, see what things read, if you have a measurable adjustment to make to things more accurate go ahead and make it.  You probably have no way to adjust you dash gauges.  And then learn what is typical for your engine, that becomes the normal range that you are going to watch.  Is it higher or lower than what you expect?

Don't fret over a few degrees or miles per hour or gallons or miles.  As long as everything is consistant you are fine.  Everything that you cannot control will make much bigger changes to things like mpg than you will ever make trying to tweak the details.

Re: Dash gauges versus silver leaf and other questions...

Reply #9 –
My coaches silverleaf trans temp gauge matches P. Wyatts. As does the dash temp gauge. 

As does my speed up the same hill.  Minor difference between the 96 400 hp with a 3,000 tow versus my 97's 450hp and a 3,600 pound tow.  50 versus 48.

My old days as a Foretravel manager allowed me multiple unit comparisons.  Never drove a 96 or 97.  No idea what's normal hence my questions.

Talked to my local cummins shop service manager today and finally think I  understand the RMPG's changes without a temp gauge  or silverleaf temp gauge change.  I was trying to make sure I had no defective cooling system components like the fan controller running at high speed under a low load.

Found out there is really no way to know with my current monitoring setup.

The hydraulic fan speed control is in the engines coolant output metal pipe. 

The temp gauges are in the return to engine coolant lines from the radiator.  None in the output pipe.

If Foretravel installed a somewhat smaller radiator in my 97 there is no way to know as the fan seems to have enough speed/flow  capacity to keep the motor cool.

I wonder if Foretravel may have changed the radiators size with the ISM's initial use.

I cannot change my m11 celect plus to a ISM without spending $15k. 

That's a lot for better power and fuel mileage.  P

Just trying to get the info I used to get working for them now.

The 600hp Spartan K3 has a massive tall, square, thick radiator  to cool.

I might tinker with the torque as I understand the engine is actually set at 1220 pound feet torque versus the advertised 1450.

Just trying to verify there are no bad parts in the system before I decide to pump it up.

My experience long ago was more power gave better mileage and the cummins shop guy agreed.

Subject to burning it down or failing parts. 

Love to know if the ISM has the same cooling package as mine.

If the parts are the same and mine are in correct good condition then a torque increase might be possible.

I almost wonder if Foretravel had cummins turn down the torque to not have their phone ring with the inevitable calls that the temp gauge moved off the peg.

Delicate balancing act between power/mileage/engine temp.

Lower torque would make the cooling systems reserves much larger and get less owners in trouble.

Shop guy says he can control the torque per gear.  Not a torque increase until third gear and converter lockup in 3-6 gear.

Yes I understand it will run a bit hotter.  Seems to have enough reserve cooling.  Just trying to make sure.

My aqua hot does not run the 110 volt side on the inverter during testing today.

The variations on the RMPG is the cooling fan idling.  Normally is under load it seems.  Enough that the cooling fan always runs fairly hard dropping the mileage always.

Would have to sensor the cooling pipe next to the hydraulic fan control to actually see what's really going on.

Fan on high consumes 36hp according to the shop guy.  A/c fan 2hp.  Alternator 6hp?

Love some rough measurements of the cooling packages dimensions on a ISM versus mine.

The ISM may not run as hot in the output pipe letting the fan run slower which then consumes less power.  Or just needs less throttle to do the same work?

Too much thinking is probably my problem but I have tinkered with rvs engines since the 80's.

More IS better.  Normally

Next is the exhaust and air filter changeout I think.

Interesting that Foretravel may have learned from the original U300's that the hp rating is important for the owners pride and bragging rights but to turn down the torque to reduce issues?

Went from 277/840 to 300/820.  277 was faster in a side by side runout.  Noticeably.



Re: Dash gauges versus silver leaf and other questions...

Reply #10 –
Bob,

"Talked to my local cummins shop service manager today and finally think I  understand the RMPG's changes without a temp gauge  or silverleaf temp gauge change.  I was trying to make sure I had no defective cooling system components like the fan controller running at high speed under a low load."

Not sure what you mean.  VMSpc calculates RMPG (recent miles per gallon).  It is a moving average mpg over time. It does not depend on a temperature gauge. 

Re: Dash gauges versus silver leaf and other questions...

Reply #11 –
Quote from: Roger & Susan in Home2 –
Bob,

"Talked to my local cummins shop service manager today and finally think I  understand the RMPG's changes without a temp gauge  or silverleaf temp gauge change.  I was trying to make sure I had no defective cooling system components like the fan controller running at high speed under a low load."

Not sure what you mean.  VMSpc calculates RMPG (recent miles per gallon).  It is a moving average mpg over time. It does not depend on a temperature gauge. 

I was trying relate either engine temp gauge to the RMPG.  my concern is the tooling fan on high what percentage and under what conditions.

Trying to see if there is enough room in the cooling package to bump up the torque.

Foretravel turned it down and restricted the tow to 6k pounds for what reason?

My marketing side that Foretravel might have picked up on says to restrict the performance of any new model then slowly increase the power every year.

The coach body  being raised over the chassis in the 99's as I understand happened  would allow a taller radiator with keeping a flat floor in the bedroom.

If you deflate a 99 coach I understand the tires do not hit the floor. 

I am putting 2 and 2 together and getting 5 or 6.  Maybe.....

I am going to figure out the stock systems limits before I consider turning it up.
 

Re: Dash gauges versus silver leaf and other questions...

Reply #12 –
It is 02 before they raised the coach not to sit on the tires.