oil shut down sending unit on frame rail mci

[christopher]

On my 6v92 5c can you install a pushbutton switch to overide the oil pressure shut down just when starting?
My coach starts right up when cold. i do not have to step on the accellerator.
on the 2nd or warmed up start i have to pump the accelerator while starting for the engine to run.

I already replaced the oil sending unit and fuel pressure is good(have gauge attachedto system and raycor, no bubbles).\
anyone have any thoughts?
Thanx
Chris
mci5c

[JackConrad]

Nor sure on your 5C, but on our MC-8, I simply hold the start button until I have oil pressure. The fuel pressure switch on the fuel filter disengages the starter as soon as you have fuel pressure and the start button overrides the low oil shutdown.  Jack

[gumpy]

What Jack said.

Sounds like possibly you don't understand the safety shutdown system, and how it works when starting the bus.

First, make sure your fuel pressure switch is wired to the starter, and works properly. Then try holding the start button in till the oil pressure light on the panel goes out. On my 9, it will blink off once and back on (because there's a flasher in the circuit). When it goes out the second time, I release the button and it runs. If I release the button too soon, it dies because of low oil pressure.

It's critical that the fuel pressure switch is working properly because that's what turns off the starter while you are holding the start button.

craig

[christopher]

men
i forgot to mention i dont have a start button. its a key switch. the engine catches to start then quits.
thanx'
chris

[JackConrad]

the engine catches to start then quits.

Does it quit at the same time you release the key from the start position?  Jack

[gumpy]

Whether you're using a button or key, the safety system should act the same way. With the key, you should continue to hold the key in the start position until the oil pressure light has gone out on the dash panel. Again, it's critical that the fuel pressure switch be in good working order.

[christopher]

jack
if i lay on the key it will grind the starter.

[JackConrad]

    That means the fuel pressure switch is not shutting down the starter. It is possible that the switch has been taken out of the circuit. I will have to look at my Schematic to see exactly how the circuit is wired, but I think the wire from the start position of your key switch goes to the starter relay in the rear panel. The ground that completes this control circuit should go to the fuel pressure switch, and from the switch to ground. When you have fuel pressure, it disconnects the ground on this control circuit causing the contacts in the realy to open disconnecting the power to the starter solenoid.  Jack

[buswarrior]

Good explanation Jack.

Another alternative is to disable the oil pressure related shut down circuit, and the hot engine one too.

These were in place to defend against hired help who had no concern for the life of the engine and would drive on with warning lights illuminated.

A busnut won't do that, and may want to make their own decision of the cost/benefit of shutting down a sick engine out in the left lane of a busy highway at speed...

happy coaching!
buswarrior

[LUKE at US COACH]

Hi Buswarrier & Folks:

Buswarrier, we have met and I have never ever disagreed with anything that you have ever posted here, or elsewhere, but tonight I do!!!!

Folks, make sure that all of your safety shut downs work!!!!!

If Not, it could cost you your entire project if you are not able to afford to replace your lost engine.  The safties are there for a reason.  That is to alert you that you have a problem going on 30 or 35 feet behind you.

On any vehicle, make sure your SHUT-DOWNS are working.  And "Never Leave Home Wihout Them", as your project coach and your pocketbook are dependent upon them!!!

I Hope this HELPS!!!

Happy & SAFE!! Bussin to ALL.

LUKE at  US COACH

[gumpy]

Gotta agree with Luke. Make sure the system works, but just as important, make sure you understand how it works, and why it's there.

[buswarrior]

No problem Luke!

Variety is the spice of busnuts!

happy coaching!
buswarrior