Fuel cut-off valve/solenoid?

[Bob (WA0MQE)]

I've read that Cummin's says when your engine has sat without being run for a long time they recommend disconnecting the +12volt lead going to the Fuel Cut-off and then crank the engine with the starter until you see the oil pressure rise on the oil pressure gauge.

They even recommend to make it easier to put a switch in line so you don't have to pull the wire off.

My question is does anyone know where this Fuel Cut-off valve/solenoid is? What does it look like?

[deandec]

On my C8.3L Cummins the solenoid is mounted near the Fuel Injection Pump. Its moveable shaft is linked to the throttle assembly I think. The shaft jerks up and stays up to release fuel when the ignition key is turned on.

Of course my rig is 10 years older and technology may have changed.

[vtwinwilly]

Originally Posted by Bob (WA0MQE)

I've read that Cummin's says when your engine has sat without being run for a long time they recommend disconnecting the +12volt lead going to the Fuel Cut-off and then crank the engine with the starter until you see the oil pressure rise on the oil pressure gauge.

They even recommend to make it easier to put a switch in line so you don't have to pull the wire off.

My question is does anyone know where this Fuel Cut-off valve/solenoid is? What does it look like?

I'm curious... Do they specify how long "a long time" is?

Every time I start mine, it takes a second or two before the oil pressure comes up. Doesn't matter if it's been sitting a day or a month.

BTW... previous poster is correct. Your fuel shut off solenoid is mounted to the side of your fuel pump, next to your injector rail, pointing downward. This means that looking from the top, all you'll see is the butt end of it. What you'll see from the top is a round cylinder about 2 inches in diameter mounted in a metal bracket with wires coming out of the backend. The wires are only about 8 inches log and plug into the wiring harness. This is where you disconnect it.

The other end of the solenoid has a plunger with a connecting shaft that connects to the fuel control valve. You probably can't see that side, but you should be able to reach around the mounting bracket a feel it.

Also, the solenoid has two circuits a Pull circuit, and a hold circuit. The Pull circuit engages a fairly strong electro-magnet that retracts the plunger when you turn the key on. Once retracted, the hold circuit takes over to hold the plunger in place. If you install a switch you'll need to test which wire is the "Pull" wire ... Or I suppose you could install a double throw switch and just shut both the Pull and the Hold circuits off.

Hope some of this has been helpful.

BB

[a k]

Too much work. Oil pressure is going to come up or it won't. I think that when you turn it over ,it won't make the solenoid until the ECM sees oil pressure. I might be wrong.

[vtwinwilly]

Ooops... my bad!

Bob,

I just read the fine print in you sig and see you have a 2006 model. What I told you was for the C8.3L. Reviewing your post, I'm not even sure which engine you have, but the post right before this one may be right. ECM might control solenoid based on oil pressure, but that would seem inconsistent with what your manual says.

As I've said before, after sitting a day or more, mine always takes 1 - 2 seconds for oil pressure to come up and it's got 132K on the clock and counting. I'm not sure this is something to spend a lot of time worrying about.

BB

[tims52ford]

On most cummins engines, the fuel solenoid is mounted on top of the fuel pump. It will have one small wire connecting it to the fuel pump solenoid. it should be held in place with a nut. remove it with a three eights wrench. good luck.

[powerboatr]

my 08 cummins manual says its not required because the ecm will not let it run if the oil pressure is not up...
mine comes up pretty darn fast to


i think the mechanical engines are the only ones to do this with, as the electronics are not there to protect the engine. so to speak

[Bob (WA0MQE)]

In regards to "how long." If memory serves I believe it's 30 days or more. Also, if memory serves I think I read about this on the Cummins web site.

Also, it makes since as "powerboatr" states, the engine won't start until the ECM notices there is ample oil pressure. On pre-ECM engines, although historically it doesn't seem to be much of an issue, it makes since to make sure there is oil pushed to all oiled surfaces prior to the engine starting. On many industrial engines, large generators, etc. they have a pre-oiler which is an electric pump that pressurizes and pumps oil throughout the entire engine and use these prior to starting the engine.

I'm sure this is just Cummins' way of helping to prolong engine life as much as possible.

Thanks for the replies.

[Navy Flier]

When I first got my coach I saw that "disconnect the wire over 30 days" statement in the manual and called Cummins about it. The rep said it is not necessary and my impression from the way he answered the question was that it has to be a very unique set of circumstances to even consider doing it. Like many others my coach sits unstarted over the winter. In my case I am living in it in Florida. When I am ready to leave it starts just like it does when I start it every day. Start right up and the oil pressure comes up after less than five seconds. I think the biggest problem with the manual is that it is written for everyone on the planet that is using a Cummins engine regardless of vehicle type.

[daveshan]

Originally Posted by powerboatr

my 08 cummins manual says its not required because the ecm will not let it run if the oil pressure is not up...
mine comes up pretty darn fast to


i think the mechanical engines are the only ones to do this with, as the electronics are not there to protect the engine. so to speak

My '99 doesn't have the cut off solenoid. I suspected it (back when I thought it had one) was causing a no-start. The mechanic that came out said the electronically controlled engines no longer had a cutoff solenoid as that function was controlled by the ECM.