Master Power Switch

[TNriverjet]

I did a bit of searching and did not find a thread covering this.

Occasionally the engine does not shut down when I switch off master power. If I switch on and back off, it usually shuts down. Once I had to cycle the switch twice to get it shut down.

Is this just a bad switch or a deeper problem like bad grounding?

 

[coachgeo]

may not be dash switch..... but the fuel shut off solenoid that is depowered by dash switch... assuming that is the means by which these CAT engines are shut down.

 

[Coffey1]

Yup mine did this one time. And yes that switch does energize the fuel solenoid.

 

[DieselInfantry711]

Check your fuel shut off solenoid for power and ground. It's on the governor. If you have it there it's not the switch but check it when it does the problem that way you know.


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[TNriverjet]

I should mention as part of the equation that low voltage may be the problem. I have two batteries that were revived on the NOCO genius charger with little effort. I have one battery that took some time, but finally came back via NOCO. One was DOA, so it was replaced with a new 6TL from NAPA. I've been cautioned that using a mix of batteries like this may prevent the charging system from effectively maintaining the system. I've had to recharge once via slave port since all those batteries were installed together. I may need to pull them all out and charge individually to see if I have a "weak link" in the mix. SS member tnmogger let me know I may ruin my new battery by installing with the old ones. I felt like the two that came up quickly were fine, but I am wondering if the other original that took some work to "repair" via NOCO charging is causing me problems.

All that to say again, a lower than normal voltage situation may be the reason that fuel solenoid isn't shutting down consistently every time. Thoughts?

 

[Coffey1]

Don't think that's the issue mine has brand new batteries and did it.

 

[Coffey1]

Come to think about it the relay may be sticking.

 

[TNriverjet]

Is the relay you reference in the PDP or on the fuel shutoff solenoid itself?

Come to think about it the relay may be sticking.

 

[tennmogger]

The fuel solenoid should close when power is removed. Low battery (really low!) would therefore have the opposite effect of shutting off the engine when you didn't want it off.

To be refusing to turn off, the solenoid might be sticking, as if the 'slug' is not sliding in the coil, or maybe the valve itself is sticky. Maybe someone has had one of these apart and can shed some light on the subject?

Chris, do you ever run a fuel additive? A good dose of Diesel additive/cleaner might have a positive effect to clean out the fuel system on your relatively new truck.

 

[TNriverjet]

The fuel solenoid should close when power is removed. Low battery (really low!) would therefore have the opposite effect of shutting off the engine when you didn't want it off.
To be refusing to turn off, the solenoid might be sticking, as if the 'slug' is not sliding in the coil, or maybe the valve itself is sticky. Maybe someone has had one of these apart and can shed some light on the subject?
Chris, do you ever run a fuel additive? A good dose of Diesel additive/cleaner might have a positive effect to clean out the fuel system on your relatively new truck.

I do run fuel additive. Usually the Power Service white bottle. I have also run some Optilube XPD in previous engines, but am no longer buying that since my VW TDI was "returned to sender" in the emissions scandal buy back. I suppose I have driven the 1083 about 150-200 miles with additive in the tank. Probably not enough to make a difference on the solenoid plunger yet.

I will "open the hood" this weekend and check electrical connections on the fuel shutoff solenoid.

 

[snowtrac nome]

the plunger is an electromagnetic switch that is sealed from the fuel system fuel additive wont help if the switch is doing its job and it still doesn't shut down I would be suspect of rack adjustments.

 

[TNriverjet]

the plunger is an electromagnetic switch that is sealed from the fuel system fuel additive wont help if the switch is doing its job and it still doesn't shut down I would be suspect of rack adjustments.

Thx snowtrac. Another good item to check while the hood is up. Diagnosis of this symptom may be getting my own thread off topic, but I've also had some weird start ups... It fires and then acts like it is only hitting on 3 or 4 cylinders for a few seconds... Again, could be the solenoid or the rack adjustments.

 

[GIJake777]

Thx snowtrac. Another good item to check while the hood is up. Diagnosis of this symptom may be getting my own thread off topic, but I've also had some weird start ups... It fires and then acts like it is only hitting on 3 or 4 cylinders for a few seconds... Again, could be the solenoid or the rack adjustments.

Did you ever figure out the shutdown problem? I'm having a problem that is somewhat similar to this. My problem is that the MBDU (Manual Battery Disconnect Unit) doesn't shut the engine down when it is turned off. It still shuts down from the master power switch in the cab, but turning off the external main battery switch isn't shutting the engine down.

 

[Ronmar]

Did you ever figure out the shutdown problem? I'm having a problem that is somewhat similar to this. My problem is that the MBDU (Manual Battery Disconnect Unit) doesn't shut the engine down when it is turned off. It still shuts down from the master power switch in the cab, but turning off the external main battery switch isn't shutting the engine down.

The external manual battery sw near the batteries? That wont shutdown the engine, like the batt disconnect relays located near it, it simply disconnects the batteries. If the engine is running, the alt continues to power the truck..

 

[GIJake777]

The external manual battery sw near the batteries? That wont shutdown the engine, like the batt disconnect relays located near it, it simply disconnects the batteries. If the engine is running, the alt continues to power the truck..

Yeah… that’s what I was thinking too, but my buddy insisted it should work that way. I figured it out after looking at the schematics for a couple hours…