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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: chazwood on January 03, 2013, 06:11:53 PM



Title: Didn't expect that
Post by: chazwood on January 03, 2013, 06:11:53 PM
Was in the electric panel under the driver window with the bus running and touched a wire to the REI radio system amp to supply a voltage to see if it still worked and spark-poof-silence! The bus shut off and now the whole thing is dead as a door nail. I had no idea a single small  spark could wipe out the whole bus!
 Don't even know where to start.

Chaz
92 MCI 102c3


Title: Re: Didn't expect that
Post by: chazwood on January 03, 2013, 06:24:16 PM
Having recovered from the initial shock and probed a bit further it seems everything works that would work without the ignition switch being on but everything that relies  on the ignition is dead. Ideas?


Title: Re: Didn't expect that
Post by: robertglines1 on January 03, 2013, 06:37:16 PM
Ill guess: inline fuse to DDEC off battery  look for inline fuse holder in front elect compartment or battery compartment.    Maybe BK will chime in I think he had problem some years ago.  Bob


Title: Re: Didn't expect that
Post by: lostagain on January 03, 2013, 06:42:18 PM
You got to get out your manual and look for fuses.

JC


Title: Re: Didn't expect that
Post by: chazwood on January 03, 2013, 06:57:09 PM
Dang, don't have a manual


Title: Re: Didn't expect that
Post by: robertglines1 on January 03, 2013, 07:06:27 PM
You should have 12 volt feed going from switch back to ddec. on my 89 prevost there was a inline fuse in the front elect compartment after the ign switch.  Some have a 12 volt selonoid (sp) activated by ign switch.  Get your volt meter out.  Some had a inline fuse rite at battery tap (12 volt)  all possibilities.  I don't have a manual for your coach. Hopefully a MCI guy will chime in.  My last MCI was mechanical.   Bob


Title: Re: Didn't expect that
Post by: Boomer on January 03, 2013, 09:17:15 PM
Try asking your questions on the MCI forum, MCI Bus Talk.com
Someone there will have the answer.


Title: Re: Didn't expect that
Post by: chazwood on January 04, 2013, 06:17:11 AM
What is a ddec? This engine is a cummins l10.
Thanks for your help.


Title: Re: Didn't expect that
Post by: expressbus on January 04, 2013, 06:57:02 AM
DDEC = Detroit Diesel Engine/Electronic Control. Perhaps you should add your engine type to you signature information. Then we will all know you do not have DDEC.

Just saying ...


Title: Re: Didn't expect that
Post by: robertglines1 on January 04, 2013, 08:38:22 AM
Same general idea if it has a electric fuel shut off. Was assumed that most Mci had detroit and that year DDEC.  Good luck!  Bob


Title: Re: Didn't expect that
Post by: chazwood on January 04, 2013, 02:35:19 PM
Update! The Po connected the radio cutoff switch to the master control breaker. We fried the breaker when we shorted the radio controller. Moved the master control wiring to an empty breaker and she started right up.


Title: Re: Didn't expect that
Post by: robertglines1 on January 04, 2013, 05:05:11 PM
Good outcome! Glad you worked it out.  Bob


Title: Re: Didn't expect that
Post by: chazwood on January 05, 2013, 07:59:48 AM
Thanks ! The kids were running around the house with the touchdown sign when it started.












 Ok, maybe I was too. :)


Title: Re: Didn't expect that
Post by: Mex-Busnut on January 05, 2013, 08:50:11 AM
Chazwood:

Glad to hear you got it up and running! What part of the galaxy is home base?

How do you like that Cummins L-10? How does it do on fuel economy? A lot of the older buses here in Mexico that came with 8V71 or 6V92TA Detroits were upgraded with the Cummins L-10.

 


Title: Re: Re: Re: Didn't expect that
Post by: Seangie on January 05, 2013, 09:18:11 AM
Thanks ! The kids were running around the house with the touchdown sign when it started.

Awesomeness ;)


Title: Re: Didn't expect that
Post by: chazwood on January 06, 2013, 08:39:07 AM
The l10 is pretty good on fuel around 7.5 it seems to be a simple straight forward engine. It starts instantly, runs cool and seems happy to be alive until you hit the slightest up hill. Then it dogs down like it's trying to climb a cliff. No amount of standing on the pedal makes the smallest difference. I haven't broken down the PT fuel pump, but I suspect if there is some kind of rubber diaphragm in there that reacts to vacuum and tells the fuel pump to pour on fuel, it's ruptured.
It has no acceleration, no smoke, and no indication that it's ever in the slightest bit of a hurry. I am determined to make this thing fly if it's the last thing I do.
Other than that I love it.
My other bus is a mci9 with a 6v92.
When I drag race my son he kicks my tail with it.
He's doing 40 up hills I do 17 on.
Not good for the old self esteem. :)


Title: Re: Didn't expect that
Post by: Mex-Busnut on January 06, 2013, 03:26:13 PM
Wow! I am amazed, especially seeing how popular the L-10 was here in Mexico, and the fact that everywhere we go we are climbing mountains.

Does your L-10 have a turbo on it?


Title: Re: Didn't expect that
Post by: chazwood on January 07, 2013, 07:44:20 AM
Yes, I had it apart just last week. It spins very smooth and has no leaks. Don't think the turbo is the culprit.
 It feels to me like the fuel volume and pressure stay constant no matter how the pedal is depressed. Down hill, no load; acceleration ok. Uphill, under load; get out and push.:( 
It will go 75 on the flats.


Title: Re: Didn't expect that
Post by: Sam 4106 on January 07, 2013, 08:31:20 AM
"Don't think the turbo is the culprit."

Do you have a boost pressure gauge? If so, how does the boost pressure compare to the engine specs? Have you checked your air filter? Do you get smoking on hard acceleration? Is your fuel pump producing the pressure it should? Is there any restriction in your exhaust system? These are a few thoughts about your engine being under powered. Hope you find the solution without too much expense.

Good luck, Sam


Title: Re: Didn't expect that
Post by: poppi on January 07, 2013, 11:06:45 AM

  Just a few thoughts with a lot of ifs.

  I have a L10 with a ZF auto-tran......So I don't know what transmission you are running. (makes
  a difference). I also don't know if you had the differential regeared for the higher torque/lower rpm. (makes a difference)

   IF the tranny doesn't down shift soon enough the engine will bog down
   If the bus has the stock diff for the 2stroke engine then the engine will bog down
   If the driver doesn't anticipates the slightest up hill the engine can bog down.

  With time and experimenting it might just be an operator fix.

  Mine goes great but if I let it bog down even the slightest I pay the price of slowing to a crawl.
  15mph vs 45mph on the passes around here.

  Have fun
Skip


Title: Re: Didn't expect that
Post by: chazwood on January 08, 2013, 03:38:33 PM
How do you prevent it from bogging down?


Title: Re: Didn't expect that
Post by: chazwood on January 08, 2013, 03:42:49 PM
My trans is an auto Allison


Title: Re: Didn't expect that
Post by: chazwood on January 08, 2013, 03:45:42 PM
When this thing starts up a hill, the lower the tranny shifts the faster she slows down. She chugs along pretty good in 4th but don't let her smell 3rd.....she drops off pretty quick in third.


Title: Re: Didn't expect that
Post by: chazwood on January 08, 2013, 03:47:36 PM
"Don't think the turbo is the culprit."

Do you have a boost pressure gauge? If so, how does the boost pressure compare to the engine specs? Have you checked your air filter? Do you get smoking on hard acceleration? Is your fuel pump producing the pressure it should? Is there any restriction in your exhaust system? These are a few thoughts about your engine being under powered. Hope you find the solution without too much expense.

Good luck, Sam
Don't have those testing tools. Where you you find them for this engine?


Title: Re: Didn't expect that
Post by: Sam 4106 on January 08, 2013, 05:01:44 PM
The boost pressure gauge was fairly simple on my DD 8V92TA. There was a plug in the air horn between the turbo and the intake. I installed an 1/8" tubing fitting where the plug was and ran the 1/8" tubing on the outside of the bus into the drivers window, temporarily. There I used a 30 PSI gauge, you may need a higher pressure, from the local hydraulic hose store, to check the boost pressure. I had 22 PSI at 2100 RPM in third gear on a steep hill. You will have to select the gear that gives you enough load, yet allow the engine to get up to governed speed, on a steep hill. To be sure there was no restriction in the air filter I installed a new element for the test. Probably not necessary if your air filter doesn't have too many miles on it. Then compare the PSI reading you get to the Specs for your engine, which you should find on the internet. Checking the fuel pump pressure would probably require removing the pump and taking it to a pump and injector shop. They should be able to tell you if the pump pressure is within your engine's parameters. For exhaust restrictions look for partly crushed pipes, especially the tail pipe after the muffler.

Did your bus come from the factory with the L10 engine? If not, maybe the transmission shift points aren't right for your engine. You can manually shift down to keep the engine speed higher, to keep the engine from bogging down too. Still hope you can find the solution without too much expense.

Good luck, Sam


Title: Re: Didn't expect that
Post by: lostagain on January 08, 2013, 05:06:44 PM
Chazwood,

you have to shift your Allison manually. When going up a hill, as soon as it starts slowing down, watch your tach. and down shift into 3rd as soon as possible. Whatever rpm it is that it upshifts at. Probably around 1700 rpm, depending on your governed rpm and gearing. That will put your engine back at or near the governor, where the power is. If you don't do that, the Allison will let the engine rpm slow right down where there no torque and it will bog down. Those transmissions are not smart enough, they need supervision.

JC