Mep 831a

[Smitch86]

Hello I have two mep 831a generators both run great . One has a fault that just started showing up. It’s the low oil pressure one. The only thing the tm says is to check the valves…… do these have an oil pressure sensor? Should I try anything else other than the valves ? Doesn’t seem like the valves have anything g to do with it ? Or do they?

 

[kloppk]

Yes, there is an oil pressure switch. They fail with some frequency on the 831's.
The -13 TM has a test procedure for it. It's screwed into the block on the left down low. Operation is switch is closed with no oil pressure and open with oil pressure.
It might be the Fault Monitor itself. They fail too.

 

[Smitch86]

Yes, there is an oil pressure switch. They fail with some frequency on the 831's.
The -13 TM has a test procedure for it. It's screwed into the block on the left down low. Operation is switch is closed with no oil pressure and open with oil pressure.
It might be the Fault Monitor itself. They fail too.

Do you know where I could get a fault monitor if that was it ?

 

[kloppk]

I have a good, tested, used one available if it turns out your Fault Monitor failed.

My money is on a bad OP switch.
Easy test to determine if it's the OP switch assuming you have batteries in the set or you are slave jumping it.
Put S1 in the RUN position. Do not start it. The Low OP light should be ON. Press and release the Fault Monitor RESET button. The Low OP light should still be ON.
Put S1 in the STOP position. Disconnect 1 of the wires from the OP switch. Don't let it touch anything.
Put S1 in the RUN position. Do not start it. The Low OP light should be OFF.
If so, the OP switch is bad.

 

[MarkM]

Those oil pressure switches are a go to for these issues. Easy fix.

Mark

 

[Smitch86]

I apologize . It wasn’t the oil pressure light that is on . It’s the engine high temp light that is on. And it’s on from the beginning even when it’s cold. Where is the sensor for that ?

 

[kloppk]

I apologize . It wasn’t the oil pressure light that is on . It’s the engine high temp light that is on. And it’s on from the beginning even when it’s cold. Where is the sensor for that ?

It's screwed into the back of the engine block down low.
Operation is switch is OPEN at cold or normal operating temp. Switch is CLOSED if there is a high temp issue.

 

[Guyfang]

Might want to look at these books.

Manuals for the MEP-831A

Here are the manuals needed to work on the MEP-831A. Please ignore the schematics in the TM 9-6115-639-13&P. The more readable copy is the last uploaded file, Courtesy of Member Kurt Klopp.

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