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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: busshawg on January 26, 2009, 02:39:04 PM

Title: oil pressure regulator??
Post by: busshawg on January 26, 2009, 02:39:04 PM
Do any of you know if there is a regulator or some sort of sensor that prevents my 1984 8V71 from strating up on the first few turns of the starter? Only happens when it is colder out , which makes me believe it is building some oil pressure before it fires right up.

I suppose i could heat the oil and see if there's a difference but thought maybe someone might know, I hate starting it period, when it's quite cold

Have Fun
Title: Re: oil pressure regulator??
Post by: viento1 on January 26, 2009, 03:45:53 PM
Hello,

my 8v71 does the same thing, I have to use the overrule switch for 2-3 seconds than all is good. I find it does that when there is air pressure and no oil pressure. If there is no air or oil than it starts without hassle. I am not sure if this is a standard thing with MCI or not... my other mci did not have this issue.

Title: Re: oil pressure regulator??
Post by: JackConrad on January 26, 2009, 04:17:55 PM
Quote from: viento1 on January 26, 2009, 03:45:53 PM
Hello,
my 8v71 does the same thing, I have to use the overrule switch for 2-3 seconds than all is good. I find it does that when there is air pressure and no oil pressure. If there is no air or oil than it starts without hassle. I am not sure if this is a standard thing with MCI or not... my other mci did not have this issue.

Our MC-8 does the same thing. IF you have air pressure, as soon as you release start button, Low Oil shutdown does it's job shutting the engine off before the oil pressure builds enough to disable low oil shutdown.  There is a switch on the secondary fuel fliter to disable starter as soon as you have fuel pressure. Holding the starter button down for a couple seconds after engine starts, until you have oil pressure will keep engine running. Holding starter button down overrides low oil shutdown and fuel pressure switch disengages starter, At least that is how it is supposed to work.  Jack
Title: Re: oil pressure regulator??
Post by: busshawg on January 27, 2009, 11:55:58 AM
Thanks guys, I find I just hold the starter bottom down and the old girl cranks over several times until it starts, then I get the black/grey smoke for a 30 seconds or so. I'm thinking the oil pressure is low due to the cold (well below freezing) then it clears up. This is done without air pressure in the system as well. It fires right up perfectly when warm without smoke. I think the smoke when cold starting is a result of excess fuel from cranking over a few times without firing. That's kind of why I thought there must be some sort of a oil pressure regulator/shutdown . So I guess mine is working as it's supossed to.

Thanks