Author Topic: Help MCI won't Fire  (Read 10558 times)

Offline luvrbus

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Re: Help MCI won't Fire
« Reply #15 on: December 20, 2010, 04:19:57 PM »
Well that clears that up Gumpy I am not a MCI person although I have owned 2 and don't work on that bus those guys did some weird stuff,my 8 would not start till the fuel pressure came up hot or cold  


good luck
Life is short drink the good wine first

Offline gmbusguy1

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Re: Help MCI won't Fire
« Reply #16 on: December 20, 2010, 05:11:09 PM »
Just a Idea to ponder,

When I change out the fuel filters on any diesel powered machine the first step is to run the engine for a few minutes then change the filters and Run it again

never had any problem losing prime

Just my way

Chris

Offline gumpy

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Re: Help MCI won't Fire
« Reply #17 on: December 20, 2010, 06:54:56 PM »
Well that clears that up Gumpy I am not a MCI person although I have owned 2 and don't work on that bus those guys did some weird stuff,my 8 would not start till the fuel pressure came up hot or cold  


good luck

Cliff,

If I understand you, you are saying that  your bus would start but would not stay running until fuel pressure came up. If you let up on the start button too soon, it would die. Is that
correct?   This is normal, and is actually not related to the fuel pressure, but is in fact caused by the low oil pressure switch activating the safety shutdown before oil pressure comes up.
By holding the start button in until the oil pressure comes up (i.e. the dash light goes out), you are effectively overriding the safety shutdown system until the oil pressure sensor says
it's all good.

That tells me your safety system was functioning properly (at least for the override and oil pressure switch).  Doesn't say anything about the fuel switch, unless you are sure it wasn't grinding
away at the starter while you waited for the oil pressure to come up.  Those fuel switches are notorious for malfunctioning. In fact, I have a new one in the bus that I need to install when
I get to warm weather next week.

craig
Craig Shepard
Located in Minnesquito

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Offline FloridaCliff

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Re: Help MCI won't Fire
« Reply #18 on: December 21, 2010, 04:32:42 AM »
Those fuel switches are notorious for malfunctioning. In fact, I have a new one in the bus that I need to install when
I get to warm weather next week.
craig


When I first bought my coach it was bypassed by grounding it to an engine bolt.

I replaced it and had to do the same a few years later.   

Always good to know how to bypass a sensor failure, of course you better be darn sure its a sensor failure......

Cliff
1975 GMC  P8M4905A-1160    North Central Florida

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Offline gumpy

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Re: Help MCI won't Fire
« Reply #19 on: December 21, 2010, 07:53:57 PM »
Those fuel switches are notorious for malfunctioning. In fact, I have a new one in the bus that I need to install when
I get to warm weather next week.
craig


When I first bought my coach it was bypassed by grounding it to an engine bolt.

I replaced it and had to do the same a few years later.   

Always good to know how to bypass a sensor failure, of course you better be darn sure its a sensor failure......

Cliff

Yep, there's a permanent alligator clip hanging next to mine for the same reason. I've put 3 or 4 on since I've owned the coach. The last one broke and started leaking fuel all over the place.

You cannot ground the the other sensors (low water, low oil pressure, hot engine). Those sensors are normally open and close to ground when they activate, which completes the safety shutdown circuit.  But you can remove the wire and wrap it with electrical tape to keep it from grounding against the engine block. That will get you home.

Craig Shepard
Located in Minnesquito

http://bus.gumpydog.com - "Some Assembly Required"

Offline fredcliff

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Re: Help MCI won't Fire
« Reply #20 on: December 22, 2010, 06:17:25 AM »
Well here is a update! Thanks to Gumpy! we disconnected the Emergency shutoff and she fired right up and stayed running. Thanks You Gumpy!! and to everyone else who sent advice

Offline gumpy

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Re: Help MCI won't Fire
« Reply #21 on: December 22, 2010, 06:29:32 AM »
Did you isolate the bad sensor?  Which one was it?

Gotta get that fixed. There's a reason that shutoff is there :)
Craig Shepard
Located in Minnesquito

http://bus.gumpydog.com - "Some Assembly Required"

Offline fredcliff

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Re: Help MCI won't Fire
« Reply #22 on: December 22, 2010, 06:35:29 AM »
Not Yet we are headed over shortly to Isolate the bad one and fix that broken wire Thanks for the picture , Hope to meet up with you on the road soon

Offline fredcliff

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Re: Help MCI won't Fire
« Reply #23 on: December 23, 2010, 07:11:22 AM »
Started new post on this issue
« Last Edit: December 23, 2010, 07:46:17 AM by fredcliff »

Offline eddiepotts

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Re: Help MCI won't Fire
« Reply #24 on: December 23, 2010, 07:26:25 AM »
Time to start a new thread on your new question. Lets not loose those the answer for the search feature. ;)

Offline Highway Yacht

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Re: Help MCI won't Fire
« Reply #25 on: January 05, 2011, 09:06:00 PM »
Exactly how many of these sensors are there that can shut down the engine? The only one that I know where it is, is the low oil pressure sensor.

Jimmy
1979 MC-9  8V71-Turbo / HT740             * www.MciBusTalk.com *
Locust, North Carolina                           A Site Dedicated To MCI's

Online buswarrior

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Re: Help MCI won't Fire
« Reply #26 on: January 06, 2011, 06:34:54 AM »
There is a school of thought that would suggest disconnecting an auto shut down feature on a coach that the driver is also the bill payer.

Auto shut down was to protect the investment in equipment from hired drivers, who did not share the desire for economical operation... I know many, before, now and future, who would just keep driving it until it stopped moving, regardless of what was lit or ringing.

your coach, your choice!

happy coaching!
buswarrior
Frozen North, Greater Toronto Area

Offline Busted Knuckle

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Re: Help MCI won't Fire
« Reply #27 on: January 06, 2011, 07:43:38 AM »
There is a school of thought that would suggest disconnecting an auto shut down feature on a coach that the driver is also the bill payer.

Auto shut down was to protect the investment in equipment from hired drivers, who did not share the desire for economical operation... I know many, before, now and future, who would just keep driving it until it stopped moving, regardless of what was lit or ringing.
your coach, your choice!
happy coaching!
buswarrior

BW you are so correct in all of this (especially the part about hired drivers that will keep going as long as it will regardless if it breaks in half! As long as the 1/2 they are in is still moving it's all still good right?)

Now on the part I made bold. Please take note of my of our very own bus guru's post!
I make note of this not to point fingers at, demean, or insult Craig in any way, but to bring light that as he is not only a talented & knowledgeable bus guru but a personal friend as well!
But rather to point out that we all regardless how much $ or time we've spent on these buses can get "comfy" and forget to pay as much attn as we should!

http://www.busconversions.com/bbs/index.php?topic=18447.msg200144#msg200144

Now... the rest of the nightmare... errr, story....
« Reply #19 on: January 03, 2011, 09:12:44 PM »

"I feel stupid about missing this plug, even after explaining it to my friend who was helping me, but the reality of it is, this stuff can happen no matter how careful we are. This is one prime example of why the safety shutdown system on these buses should be in proper working order. When my compressor failed, it became obvious that I was not paying as close attention to my gauges as I thought I was. If I had not been paying close attention to them this time, and the safety shutdown system was not functioning, I could very easily have lost my engine.

See, I am not good for nothing. I can be used as an example.

Learn from my mistakes."

craig


Craig thank you for the complete & honest eye opener!
This is not to make you look or feel bad, but in both our own words AN EXAMPLE! (and not a bad one either! ;))
;D  BK  ;D
Busted Knuckle aka Bryce Gaston
KY Lakeside Travel's Busted Knuckle Garage
Huntingdon, TN 12 minutes N of I-40 @ exit 108
www.kylakesidetravel.net

;D Keep SMILING it makes people wonder what yer up to! ;D (at least thats what momma always told me! ;D)

Online bevans6

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Re: Help MCI won't Fire
« Reply #28 on: January 06, 2011, 08:04:27 AM »
On my bus the auto shut down and the alarms were both disabled.  The first thing I did when i got the bus was to re-establish the low air audible alarm buzzer, but I haven't done anything with the other alarms (other than buy new diodes so I could fix it all up).  I think a good compromise is to disable the auto shut down, but make very sure the audible alarm buzzer is hooked up and working for low air, low oil pressure and high water temperature, along with their respective warning dash lights.

Brian
1980 MCI MC-5C, 8V-71T from a M-110 self propelled howitzer
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Tatamagouche, Nova Scotia

Online buswarrior

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Re: Help MCI won't Fire
« Reply #29 on: January 06, 2011, 09:52:22 AM »
Yes, let me qualify my earlier suggestion.

I most strongly recommend the warning systems be in working order, regardless of auto shut down use.

Then, the CHOICE is who shuts off the engine and where!

happy coaching!
buswarrior
Frozen North, Greater Toronto Area