27/11/24 - 06:53 AM


Author Topic: MCI 5a no power ?  (Read 4977 times)

purplewillie

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MCI 5a no power ?
« on: November 16, 2012, 11:53:33 PM »
I was in contact with the owner of a MCI that has been for sale for over a year. He told me that he parked it when he put it up for sale and this year it has no power and he thinks mice may have chewed a wire. I'm thinking it may just be stone dead batteries but until I go have a look I'm just guessing. Not sure if he means it doesn't start or no power to anything. What should I be looking for if it has no power to the lights or dash? I'm going to bring a couple of batteries with me to make sure that it's not the problem. Where can I find wiring info for this coach? I have done a fair amount of automotive wiring repair a and wired several old rods before the Painless wiring were around, just never did any electrical on a bus .  Any tips or advice is appreciated .
Mark

Offline wg4t

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Re: MCI 5a no power ?
« Reply #1 on: November 17, 2012, 07:48:27 AM »
Used to be Universal Coach in Ill, where I got all my parts & books Parts & Service.
Do not know if they are still around, but the MCI 5 manual for that serial number series would be great, There were changes s/n to later s/n units.
Good luck
Dave
MC7 20+ yrs
Foretravel w/ISM500 9+ yrs Gone
Too old to keep up.
Central Va.

Offline Bill Gerrie

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  • Phone or email. I'd be glad to help. 905-873-8929
Re: MCI 5a no power ?
« Reply #2 on: November 17, 2012, 09:07:50 AM »
purplewillie
If he means no electrical power to anything which I'm sure that is it. He has it parked so I can't see where he means a problem with the engine. You will have to have the electrical diagram or you will be looking forever. If he doesn't have it maybe somebody on the board could scan it to you. Be careful when you hook up fresh batteries as if the mice have shorted out things you may have a fire on your hands. When you hook up the final connection on the batteries make sure you don't have much of a spark. You may get a small one if he has any lights on or something that draws a small amount of power all the time.   
Bill
1965 New Look GMC TDH5303 6V92TA DDECIV & V731 ATEC with Overdrive

sommers

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Re: MCI 5a no power ?
« Reply #3 on: November 17, 2012, 10:14:53 AM »
I have heard tell of people (person) forget that the main disconnect had been thrown, but dead batts are sure suspect after a year if they were not maintained.

Ed

George Todd

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Re: MCI 5a no power ?
« Reply #4 on: November 17, 2012, 12:15:34 PM »
Mark,

Several things to think about here, before you try to start it:

1. As Ed said, if it has sat for a year, the batteries are dead.  The bus is 24 Volt, and will start fine with two charged Group 24 or larger car batteries.  Pay attention to how the old ones are connected!

2. There is a main disconnect in the right rear, check to see if it is on or off.

3. MCIs are equipped with self-resetting circuit breakers, which protect everything except the main cables.  The advice about checking for a large spark when connecting the batteries is good, but open the disconnect first, check the battery connections, then try closing the disconnect carefully and see how much of a spark you get there.

4. This bus was equipped with a rear start and run switch, and a rear stop switch, which won't disable the lights, etc, the bus just won't crank from the front if the rear run switch is off.

5. All of this style of bus has an air operated stop cylinder, which gets its air through a normally open solenoid valve called a Skinner valve.  What I am saying is that the engine will not stop when the master, or the rear stop switch are turned off, if the bus has no auxiliary air pressure.  You can look for this cylinder, about 2 inches in diameter, in the vee, with a little shaft coming out of it which moves a lever on the governor.  You can move this lever by hand to stop the engine.  Be very careful of the fan belt!

6. A bus that has sat neglected for a year may very well have condensation in the fuel tank, which will cause the injectors to stick partly open, which will cause a runaway engine!  To prevent this, a butterfly valve is installed in the air intake just above the vee. The butterfly or flapper is spring loaded, and is held in the open position by a latch which can be tripped electrically by the front and rear emergency stop switches, (if they work) or manually by your thumb.  I would find the trip latch, which is operated by another 2 inch diameter solenoid coil about 3 inches long, and get familiar with how it operates, before I tried to start the engine.  Once you find it and figure it out, trip it to make sure it closes, then push the little lever back up under the latch to the open position.  If a runaway occurs, the governor stop lever will NOT stop the engine, neither will the master switch.

7. Make sure the transmission is in neutral if it is an automatic.  Some automatic electronic shifters use air to move the transmission lever, and if the bus was shut off in drive, the transmission will still be in drive, with no air to move it into neutral.
Good luck,
G

Offline gusc

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Re: MCI 5a no power ?
« Reply #5 on: November 17, 2012, 05:40:51 PM »
Rats and mice are a major problem, if you find any nests anywhere you can be sure that they have been into the wiring - they just love wire insulation, especially the plastic kind.

I fight this problem daily.
PD4107-152
PD4104-1275
Ash Flat, AR

Offline lvmci

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Re: MCI 5a no power ?
« Reply #6 on: November 17, 2012, 11:11:39 PM »
Hi, just to clarify, in case your unfamiliar with it, the main disconnect knife switch on my 5A is located in a difficult to see area, in front passenger side bay immediately to the right of bay door opening against outside wall, mine has a has red plastic knob and is very hard throw. Additionally, the battery compartment just in front of the switch wall, has two "8D" battery's on some hard sliding trays, it has its own rubber hinged door, I have had to clean and use battery corrosion spray for better contact. Lvmci...
1989 102C3, 8V92, Allison740
Former
1966 5A, 8V71, Allison MT643

Offline Boomer

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  • ~Silversides Forever~
Re: MCI 5a no power ?
« Reply #7 on: November 18, 2012, 12:26:45 PM »
MCI eliminated the Universal Coach Parts division years ago.  Parts are now through MCI Service Parts.  Go to the web site.  It is highly doubtful that they will help you with the wiring diagrams for a coach that old (they are specific to each coach due to options).  That said, if you can find a diagram for any coach of your make/model/year, 90% of the information will cross over.  It's even getting hard to find certain parts for MC-9's from them and you know how many of them were built. HTH
'47 PD3751 Silverside, no more
'48 Kenworth XW-1 highway coach, no more
'65 Crown Supercoach, no more
'81 Eagle 10  45/102, no more
'93 Vogue IV, 40', no more
'64 PD4106

Longview, WA, USA