yikes!!!

[chazwood]

I've been working on gutting the bus for a week so for a break I changed the oil today.  Decided to fire it up. Started right up, so I checked everything out and flipped the kill switch.......nothing..... flipped it back and forth ....nothing. Stared at it really hard.....nothing. OK, what am I forgetting?....flipped every switch I could lay my hands on....nothing. Well now what do I do?  Jumped out and threw the battery disconnect...nothing. Ran back to the engine to jerk out the main wire in the distributor......................
Can't figure out how to kill it....trying to fight down the rising panic. (There is something very primal about that much steel churning with no kill switch.) I Actually thought about leaving it and posting here to find out what to do. Fear will do strange things to your mind. What if it suddenly jumps into gear and takes off....What if it revs up too high and melts down....you get the thought process, right?

.... I am now tasting the panic....Crawled into the now quite larger (since I took out the potty tank) engine compartment and stuck my finger over the end of the tiny open disconnected bathroom fitting that was leaking .....died in a second. Wow!!! No way!! What is up with that, people! They must be explaining this stuff in the manual I don't have yet.

Someone explain the whole "kill the engine concept" to me. Cuz' it kinda seems to me if you were to have compressor failure, you've got no way to kill the beast.   (Maybe that's why all those trucks are always running at the truck stops. )



How was your day?

[tekebird]

Distributor?  whats that?

[tekebird]

OK I got it now by looking at your past posts.

MC-9

No DFistributor on an MC-9 or any other diesel bus.......as there is no sparkplug

no idea what hole you plugged to shut the bus down.

but a diesel will only shut off by doing one of two things.

1. shutting off fuel
2 shutting off Combustion air.

and most are set up with a electrically controlled air operated Shutoff .....so unless you bus is aired up to a certain pint....it is not going to shut off

[luvrbus]

Chaz, I have a 1/4 in rod welded to the stop on top of the governor so I can push it to kill the engine.You don't know what panic is till you blow the oil filter with no air pressure to shut it off ( been there done that) won't happen again       Good luck

[chazwood]

I disconnected the little plastic air line to the bathroom sink and actually had it in my hands just before I started the bus ...."That will leak a little air" I said to myself, but if you had bet me $1000 bucks it would disable the kill switch, I would have taken it and laughed at you.

P.s. yes, there is no distributor, hence the     ".................... "    in my post. remember the rising panic.

[chazwood]

Chaz, I have a 1/4 in rod welded to the stop on top of the governor so I can push it to kill the engine.You don't know what panic is till you blow the oil filter with no air pressure to shut it off ( been there done that) won't happen any more  Good luck

Hang on there ..... You got what? welded to what? doing what to what?

I like the part about "won't happen any more" but you got to be more specific for the newbie.

[tekebird]

chaz,

you can manually operate the air operated shutdown seleoid, that is what he is talking about.

I suggest you purchase the manuals for your coach....a few nights perusing them will have you a bit more educated......better to know in advance rather than have an issue then come here after damage is done asking why

[chazwood]

I'm with you on the Manual Plan. Is there more than one I should get for the MC-9? (I assume I have to order it from MCI)


BTW, I'm wondering if warnings about disconecting the bathroom air are covered in the manual. Just a thought.

[dkhersh]

Chazwood, 

     I would bet it was just coinsidence that your bus ran long enough to build air up far enough to shut itself down at the time you grabed that hose.  Did you leave everything turned off while you were running around with your hands in the air??? ....lol.... I would like to have been there as I did the exact same thing the day I got in ours for the first time.  ........All just part of the insanity........

[chazwood]

That would be pretty good timing if my finger on the air leak had nothing to do with shutting her down. If you had been there you would have seen a slightly white, getting whiter, white dude, with a blank look on his face. I don't remember if (in all my frantic switch flipping) I left the kill switch on or off.

But I did disconnect the batteries. wouldn't that kill the kill switch?


In either case, waiting around till this engine decides it's good and ready to shut down seems a little backwards to me ...I mean, shouldn't I be the one who decides when and where? (I know my wife would disagree, but come on!), what if as soon as I fired it up I had to shut it down? "I'm sorry, dude, but I'm not good and ready to shut down yet ...you will have to wait" That's insane. 

Can someone post a picture of your rods on your governors... heck ,I'll even take a picture of your rods welded on your mayor or city council member ,as long as it give me a way to kill this thing when I'm ready.

Thanks.

[gus]

I agree with dk. The air built up just as you put your finger over the hole which I assume was for an air line to flush the toilet??

You cannot work the shutoff air switch manually since it is electric/air. You must have air to operate it so I guess iyou could work it without electricity but not without air, but I'm not sure you could even do that. My shutoff has the solenoid and air cylinder connected so there is no access to the air cylinder and I think the whole air cyl operation is internal.

[Tony LEE]

The bathroom valve air supply comes off the same air line that feeds the stop solenoid so all tghe air was leaking out of that open line leaving too little air to operate the stop valve.
Any time you disconnect an air line, you must blank it off.

And yes, you are correct, if the battery is disconnected after the engine starts, the stop circuit won't work either.

ALSO it is a bad idea to disconnect the battery with the engine running because the alternator output can do crazy things.

It is easy to operate the stop lever manually - it is on the rear of the top plate on an 8V71 - but on an MCI requires reaching through the fan belt so needs a bit of care.

I have a bike rack on the back so can't open the rear doors fully - so I have connected a wire to the stop lever and run it to the LH rear side door so I can stop the engine by pulling in the wire. Safer than reaching in past the belts anyway.

Some 8V71 have an electrical solenoid that trips the intake flapper and that will also stop the engine, but best to only operate it at idle except in case of emergency. It wion't operate with the battery disconnected either

If you have a manual transmission then easy to stall the engine by putting it in gear and letting out the clutch against the parking brake.


PS Helps us to know what bus and what engine we are helping you with.

[chazwood]

The bus is an 82 mc-9 with a 6v92, a 740 Allison auto and slightly retarded manual operator.

[coachconverter]

You can always stick your arm through that fast moving main belt and push the shotdown arm (term?) manually.  It looks like a rocker-arm lying on it's side.  The shut down solenoid should push a rod that moves that arm toward the front of bus to shut it down, but the solenoid can get stuck.

WARNING - don't do this with your thumb, use a stick or screwdriver or anything you value less than your hand.  I shut one down with my thumb one time and at that very second the solenoid released and ran the ram through the edge of my thumb.  Got the scar to prove it.  Ever since then, I tend to use sticks and screwdrivers for a lot of tasks like this.

Todd

[Stan]

A couple of comments to clarify some of the posts. Your engine DOES NOT have a combustion air shutdown.
Stopping the engine is accomplished by shutting off fuel to the injectors. On MCI and most other buses this is done by a normally open solenoid valve which sends air to the shut down cylinder. When you turn on your master switch it closes that valve. allowing the engine to start.  If you turn off the master switch and open the valve, nothing will happen if there is not some minimum of air pressure (about 30 PSI) to push on the shut down cylinder.

The shut down cylinder is mounted on top of the governor and pushes on the shut down lever. As pointed out, you can move that lever by hand (carefully). HTH