Silver 6V92T won't stay running

[Fredward]

I was helping my neighbor get the 6V92T in an 05 Eagle running so he can sell the bus for his girlfriend who inherited it. (long story on the sale) It has not run since 01 so we changed fuel filters drained some fuel out of the fuel line from the tank to be sure we had good flow and decent fuel. The tank is 1/2 full. After changing filters, we hooked an automotive in line electric fuel pump to the first filter and pushed fuel from the first filter thru the mechanical pump on the engine to the second filter. We kept the electric pump running and started the Detroit right up. But it won't stay running unless the electric pump is running.

Could the mechanical pump have failed just sitting for six years? The engine was supposedly rebuilt shortly before it was parked (although it does not look like a rebuilt engine to me; but who really knows)

Also, as soon as the bus aired up, the shut down skinner valve extended and the only way to keep the engine running was to unbolt the skinner and swivel it out of the way so the piston wouldn't push on the shut down lever. What would be causing that? And the engine kind of sounds like it wants to run away so we kept a little pressure on that shut down lever. But the 6V92 won't run away like an 8V71 will it?

If it ran really good, i might consider putting the engine and A740 in my MC5 except that my 871 is a really nice one. (Maybe I could just take the tranny?)

Fred

[JohnEd]

My electric pump will not flow fuel if it is off.  You may have an off switch in that pump that you didn't intend.  I thought the pump was supposed to have a by-pass line around it so when you were primed you opened the valve to let the engine pumps take over.  Thje elect pump needs to have an auto kill if the engine stops or you could dump a lot of fuel in terrible places if a line fails.

FWIW

John

[TomC]

When priming a Detroit, you hook into the secondary filter AFTER the pump to prime the engine.  I know this sounds wrong but what can happen if you prime the primary filter that goes through the fuel pump is you can blow out the seals in the fuel pump-which you might of done.  Another way to prime is to disconnect the fuel lines one at a time and fill with fuel.  Make sure the fuel filters are also topped off.  Sometimes takes a few times to do.  Good Luck, TomC

[Fredward]

John,
We just hooked up the electric pump temporarily via hose to the primary filter to push fuel to the pump and to the second filter. We filled both filters before spinning them on. Tom just mentioned that we could have blown a seal in the mechanical pump by forcing fuel through with the electric one. Now that would kind of suck, wouldn't it?

Tom,
I've got an electric pump and ball valve assembly set up on my 8V71 going to the primary filter. Am I in jeopardy of damaging the mechanical pump on that engine too? How the heck do I bleed the primary filter if I connect the pump to the secondary filter only? I have cartridge filters so I suppose I have to fill the primary one with a funnel? (It works so nice, i thought i was so smart) 

Fred

[TomC]

The secondary fuel filter after the fuel pump comes directly from Don Fairchild.  Good Luck, TomC

[Stan]

I have always used a primer pump into the filter after the engine pump. The engine pump is a gear pump (positive displacement) and if you can push any fuel through it, it is worn out. With a good engine pump, you cannot prime the engine by pumping fuel into the strainer (first filter) except by running the starter long enough to move the fuel through the second filter and then to the fuel rails. If you pump into the second filter it goes directly to the fuel rails, the engine will start and the primary will self prime (quickly if you filled it with fuel before installing).

[belfert]

Interesting note:  My Racor fuel fuel filter has a button on top that when pushed will fill the primary filter with fuel via gravity from the tank.

[Hartley]

Interesting note:  My Racor fuel fuel filter has a button on top that when pushed will fill the primary filter with fuel via gravity from the tank.

That might explain why you had fuel all over the place when you messed with the filters the other day... Too Much fuel in the tank... We TRUE Bus Nuts can't afford to have full tanks...

Just Kidding.....

[Stan]

Brian: I think the explanation for that is the engine gear fuel pump is a liquid pump so air can pass through it in the clearance between the gears and end plates. The fuel running by gravity into the strainer will push the air ahead of it through the pump and through the filter allowing the strainer to fill up but not the filter. If the fuel level in the tank is higher than the fuel pump on the engine it doesn't take much cranking to get a prime. You can accomplish the same thing with a pail of fuel held up in the air, with a syphon hose to the strainer.

[gumpy]

I've got an electric pump and ball valve assembly set up on my 8V71 going to the primary filter. Am I in jeopardy of damaging the mechanical pump on that engine too? How the heck do I bleed the primary filter if I connect the pump to the secondary filter only? I have cartridge filters so I suppose I have to fill the primary one with a funnel? (It works so nice, i thought i was so smart) 

Depends on what pump you used. You should use one that puts out less than 20 psi. It needs to be about 12-15 psi to work well. If you don't exceed the 20 psi, you can, and should, prime through the primary filter and mechanical pump.

[belfert]

Interesting note:  My Racor fuel fuel filter has a button on top that when pushed will fill the primary filter with fuel via gravity from the tank.

That might explain why you had fuel all over the place when you messed with the filters the other day... Too Much fuel in the tank... We TRUE Bus Nuts can't afford to have full tanks...

Just Kidding.....

You got me wondering now.  When the filter was back on, I had to press the button to fill the filter.  I could see the bowl on the bottom filling with the button pressed.  But, when the filter was off fuel was running out like crazy.  I suppose there might be a vacuum when the filter is on stopping fuel flow.

I always keep my tank full to stop condensation and such.  If I burn the fuel I have to pay for it some day.  I suppose if one was short on cash they could return home with a nearly empty tank and not fill it for some time.  The 150 gallon tank on my bus could also be used as a reserve for my diesel Golf during a fuel panic like after a hurricane or something if I got desperate.  I have had hard times getting diesel for my Golf when folks panic about gas prices after a hurricane.  I simply could not get to the diesel pumps at several stations.

[JohnEd]

Brian,

I have never seen the devices you mention in your posts.  I am getting a mental from the discussion though.  You mention a button that you depress and then you see the fuel bowl filling.  You sound as though you think the button is opening a port into the bowl.  Then you remove the bowl and fuel comes out and won't stop even though you are "NOT" pushing the button.  My vote is that the button vents the bowl to allow the bowl to gravity fill.  Gotta have a Gozotta to allow a gozinta.  Then when you remove the bowl the fuel will flow because there is no back pressure from a sealed bowl.  You have "pushed the red button" by removing the bowl.  What do you think?

Good luck,

John

[Nusa]

Make sure there's a lock on that fuel fill, or you may find $300 of fuel gone someday.