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Topic: Operating Checklists for Comment and Suggestions (Read 1578 times) previous topic - next topic

Re: Operating Checklists for Comment and Suggestions

Reply #25 –
I will shine a flashlight along the bottom of message and see if I can see it. Will report in a few.
John M.
John & Carm Morales

"We travel not to go anywhere, but to just go.  We travel for travel's sake.  Our great desire is to move."

Re: Operating Checklists for Comment and Suggestions

Reply #26 –
Not trying to hijack this thread with this topic.  I did find the wait to start on the panel by shining a flashlight from the back.  It is right next to the right turn signal.  Their is a long circuit board from one end to the other on the message area.  I'm not going to remove it yet.  I will wait till Monday call Foretravel and see if I even have the light in service in that area.  If I do, I will start another thread or write one of the moderators about moving my thread.
Thanks,
John M.
John & Carm Morales

"We travel not to go anywhere, but to just go.  We travel for travel's sake.  Our great desire is to move."

Re: Operating Checklists for Comment and Suggestions

Reply #27 –
Quote from: John Morales –
Not trying to hijack this thread with this topic.  I did find the wait to start on the panel by shining a flashlight from the back.  It is right next to the right turn signal.  Their is a long circuit board from one end to the other on the message area.  I'm not going to remove it yet.  I will wait till Monday call Foretravel......................
John,
Don't get all excited.
Your dash panel is a universal part for all models (U320, U295, U270) of FT.  Obviously, coach components are NOT universal across all models.  The 8.3's (depending upon year and configuration), may have intake manifold heaters.  Those coaches with heaters have a temperature sensor in the manifold, that keeps the "Wait to start" light lit until the manifold reaches its target temperature.  The temperature rapidly dissipates once the key is turned off (so those with 8.3's and the heaters, often cycle the key several times to further warm the intake manifold during cold starting conditions). Your engine does not have a manifold heater (as far as I know, none of the 11 liter engines do) and therefore the dash indication is "surplus" - not used for your coach.
HTH,
Neal
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Neal (& Brenda) Pillsbury
'02 U320 SPEC, 4200, DGFE, Build #5984
'04 Gold Wing
'07 Featherlite 24'
'14 Jeep Grand Cherokee Summit
MC #14494
Exeter, NH & LaBelle FL
Quality makes the Heart Soar long after Price is Forgotten

Re: Operating Checklists for Comment and Suggestions

Reply #28 –
Thanks Neal.  So when starting my engine am I doing the right thing by waiting for the gauges to cycle before starting the engine or can I instantly start the engine when inserting the key?  I always wait on the gauges.
John M.
John & Carm Morales

"We travel not to go anywhere, but to just go.  We travel for travel's sake.  Our great desire is to move."

Re: Operating Checklists for Comment and Suggestions

Reply #29 –
John,
 
I just checked my Foretravel Owners Manual, and you are off the hook.
 
On page 4-6 (Rev. 05-99) It says the following about that message:
 
    Wait to Start (Red) (U270/U295 only)
          Wait to start engine until red light goes out.
 
Trent
Trent and Jean Eyler
2000  U295  4003  WTFE  ISC  350
Build#5603 MC#17385

Re: Operating Checklists for Comment and Suggestions

Reply #30 –
Maybe I ought to check my owners manual also and see what it says. These coaches are all new to me. 😎
Thanks, 
John M
John & Carm Morales

"We travel not to go anywhere, but to just go.  We travel for travel's sake.  Our great desire is to move."

Re: Operating Checklists for Comment and Suggestions

Reply #31 –
Quote from: John Morales –
Maybe I ought to check my owners manual also and see what it says.
As a last resort...
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Operating Checklists for Comment and Suggestions

Reply #33 –
Quote from: John Morales –
...............So when starting my engine am I doing the right thing by waiting for the gauges to cycle before starting the engine or can I instantly start the engine when inserting the key?  I always wait on the gauges.............
Hi John,
You are doing the right thing by allowing the Speedometer and Tachometer to cycle before engaging the starter.
 
The Speedometer and the Tachometer go through a calibration sequence each time they are powered on (key turned from OFF to RUN position).  Although it MAY not damage either instrument by immediately engaging the starter, the starter draws enough current to cause the start battery bank voltage (and the whole start battery Vdc system throughout the coach, which includes the dash) to first, abruptly sag low, then spike high [when START position is released].  When the engine starts, we release the ignition key, which causes a break in the starting solenoid circuit.  With the starting solenoid circuit opened, the starter solenoid's magnetic field collapses and the starter motor return spring pulls the starter drive shaft back off the ring gear.  That opens the starter motor current contacts and starter motor current is automatically shut off. The collapse of the starter solenoid coil and the starter motor field create spikes in the start battery dc system that (without transient dissipation diodes being present -- all FT's by OEM design) cause failures in delicate instrumentation such as the Speedometer and Tachometer. 

While all of this "sagging" and "spiking" is occurring, the Speedometer and Tachometer calibration values may well be corrupted or possibly the instruments damaged, IF the disruptions occur simultaneous with the sequence of the instruments calibrating themselves.

What happens when you go directly from key OFF to START? 
    • Well, the first possibility is somewhat innocuous.  For that particular "ignition on" cycle, one or both of the instruments may be adversely affected and inaccurate, to one extent or another. 
    • The second possible result can be much more invasive and expensive:  There are many instances of FT's losing their Stewart Warner Speedometers, multiple times, "for unknown reasons" (inaccurate indications, odometers failing to "ERROR" or scrambled characters, analog speeds becoming intermittent or exhibiting failed behavior, etc.).  It would be hard to prove, but it only makes sense that rushing the ignition start sequence and superimposing these starting voltage swings and spikes on the instruments during their calibration sequence cannot be helpful.  So, it's good practice to let them finish their calibration sequence, before engaging the starter. 
    • How would one prove that the OEM design (with no Starter solenoid and starter motor transient absorption diodes) is deficient?  Well, the best way would be to prove (oscilloscope) that voltage transients actually do exist at the instruments and then subject the instruments to repeated similar voltage spike testing until failure occurs.  Then draw appropriate conclusions. 
    • A more realistic option would be to power any failure prone instruments from their own dedicated battery and then specifically avoid any stray ground paths by using only hard wires from the instruments back to their dedicated battery negative terminal.  Bet you dollars to donuts, that the instruments would not fail!
    Ever wonder why FT's have multiple failures of SW instruments, while other brands use the same SW's without failures?  The answer may lie in the OEM (lack of) starting circuits transient suppression diodes and "commoned-up" grounds at the dash, that are then just landed onto the coach frame, instead of hard wired back to the starting bank negative terminal.



    All of the above is distinctly separate from and has nothing to do with the original question that you asked regarding the  "Wait to Start" Red warning on the dash.  The "Wait to Start" dash warning is strictly associated with allowing the intake manifold heater time enough to sufficiently prepare the manifold mixture for a cold weather start.

    HTH,
    Neal
The selected media item is not currently available.
Neal (& Brenda) Pillsbury
'02 U320 SPEC, 4200, DGFE, Build #5984
'04 Gold Wing
'07 Featherlite 24'
'14 Jeep Grand Cherokee Summit
MC #14494
Exeter, NH & LaBelle FL
Quality makes the Heart Soar long after Price is Forgotten

Re: Operating Checklists for Comment and Suggestions

Reply #34 –
 Daily, I check one tire, bump it and the rest,  Check the oil , light it, and turn on the 4 ways and headlights. Walk around check the lights , basement doors ,awnings, ant, and check any load is secure.  Verify purge,  pump the brakes a couple of times checking rebuild time.
  Load CD player with"Majic Bus" first. 

 Preflight/ weekly, is more involved, drip check - checking all fluids, hubs, maybe re-torque the wheels,  airfilter. 

Re: Operating Checklists for Comment and Suggestions

Reply #35 –
This may be a little obvious, but since you're making a checklist, check the inside. Doors latched, refrigerator closed, loose items secured, and all drawers checked. My last move I checked everything inside and out, and got to the first signal and looked over to see my soda sitting on the living room table. DOH!
AKA Chuck
1993 U280 40' WTB, Build 4345, CUM 8.3 "Falcor", 2010 Honda CRV TOAD (Spock), 970W solar on roof
Full-Time traveler between Quartzsite AZ, Longview WA, Ellendale ND, and Lake City SD
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Re: Operating Checklists for Comment and Suggestions

Reply #36 –
Neal,

Regarding the Back EMF from the starter, would it be a good idea to place a hefty 16 or so volt crowbar across the battery terminals? Or even a huge diode in reverse polarity? Seems either one would reduce the spikes to the electrical system.
Jim

2002 U320
Jim Frerichs
2002 U320 42'

Re: Operating Checklists for Comment and Suggestions

Reply #37 –
Quote from: Jim Frerichs –
Neal,

Regarding the Back EMF from the starter, would it be a good idea to place a hefty 16 or so volt crowbar across the battery terminals? Or even a huge diode in reverse polarity? Seems either one would reduce the spikes to the electrical system.
Jim

2002 U320


Hey Jim, finally found a bit of time to get back to you,
The better solution is to install a Schottky diode, but as close to the source of the EMF as possible.

Why a Schottky?  Because a properly sized Schottky has by far the fastest response and the least voltage drop (therefore least heating) of the various diode options.  Schottkys, when switched from reverse to forward bias, are several times faster and have far less resistance than silicone and zener diodes.  Why aren't they used everywhere?  Because they have far more leakage when reverse biased, so they are wasteful of their electrons.

Why as close as possible to the inductor (relay, motor, solenoid, etc.) that is causing the "EMF kick" (EMF field collapse)?  Because then there will be the lowest chance of stray ground paths, perhaps even reverse currents through things like a Speedometer or Tachometer that is doing its "once per start calibration sequence" and various other Vdc lights/LEDs/loads/ control boards/ etc. 

As you know, "Electromotive Force" (EMF) "backflow" damage occurs because when any inductor suddenly has its current flow shut off, it's electromotive force field (think magnetic field) resists current flow change and wants to keep the current flowing at exactly the same rate after as before shutoff.  Now even if the inductor's EMF field was built from just a 12 Vdc power source and was built over time using a relatively small current flow, when you open that switch or contact (think of something with some robust current through it, like the starter solenoid contact) AND you don't provide a discharge flow path for the solenoid coil's EMF to dissipate, you have created a monster!  The EMF can essentially instantaneously built to hundreds or even thousand's of volts until something GIVES.  The something that normally GIVES is the arc that occurs across the relay/solenoid/motor starter/etc. relay contacts or switch contacts.  I = E/R, right?  If R goes to infinity (when the contact opens) and I (by Newton's Law and inductor rules) stays the same, that means E goes to infinity as well. 

Now the potential may be very high in terms of volts, but it doesn't take much current (maybe just a fraction of an amp [tenths or hundredths of amps]) to collapse and dissipate the field.  So, that's generally not fatal to the contacts, at least not until many repetitions, but transistors in Speedometers and any manner of other electronic devices are not as forgiving of the short but very powerful voltage spikes.  So it is best to keep the dissipating diode as close to the inductor as possible so no other "stray" paths get a chance to become involved.  Think in terms of "When it comes to inductor field dissipation", the reverse to forward bias switchover time must be fast (try to imagine shorter than instantaneous) and the length of the conductor(s) involved must be kept as short as possible to the EMF source.  If you do that, the "EMF Kick" will be around 0.5Vdc and won't be felt anywhere further away than your connection leads.

Others had asked before about the random presence of ignition solenoid suppression diodes and our "members in the know" (Red Tractor - Ron) have correctly advised that FOT installed diodes when (at least) some coaches came back in for service.

Ignition Solonoid Question

Others, not recognizing the importance and not knowing what they don't know, were questioning why some ignition solenoids have diodes and others do not.  Then, because not all coaches have them, the diodes were considered to be superfluous and were removed.  BTW, some ignition solenoids have self-contained diodes. The diodes are there for good reason - don't remove them.  Test them, yes, because they can fail to a shorted (example of Yetch's solenoid that he and Aubrey found would not reliabley start his coach) or an open condition.  When they fail, they can cause the solenoid to either fail to fire (Yetch) or become electronically noisy when de-energized. 

To answer Brett's request, later in that same thread, for an easy to understand answer and a part number for a Radio Shack diode that fits all relays and solenoids: unfortunately, there is no easy answer because while the Schottky is the type of diode to use, too high a voltage rating (for the anticipated EMF potential and the current that the diode must be able to dissipate) and you will sacrifice efficiency (switching time and leakage), while too low a current rating and the diode will quickly lose all of its magic smoke, rendering it worthless.

A "Thumbrule", if you back me into a corner and promise not to tell, is to use a Schottky that is rated for about 4X the coil voltage and about 10X the coil current.

HTH,
Neal
The selected media item is not currently available.
Neal (& Brenda) Pillsbury
'02 U320 SPEC, 4200, DGFE, Build #5984
'04 Gold Wing
'07 Featherlite 24'
'14 Jeep Grand Cherokee Summit
MC #14494
Exeter, NH & LaBelle FL
Quality makes the Heart Soar long after Price is Forgotten

Re: Operating Checklists for Comment and Suggestions

Reply #38 –
Thanks Neal for all of the info.
John M.
John & Carm Morales

"We travel not to go anywhere, but to just go.  We travel for travel's sake.  Our great desire is to move."

Re: Operating Checklists for Comment and Suggestions

Reply #39 –
Nweal,

Sounds as though I need to visit Digi-Key or Mouser to find Schottkys at those values.

Thanks for your analysis.
Jim
Jim Frerichs
2002 U320 42'