High oil pressure on MEP-805B

[diogenescreosote]

My MEP-805B shows a high oil pressure fault while it's starting cold. If I keep cranking it while holding fault reset for about 30 seconds, it starts up and runs ok. This is the same amount of time it takes for the smoke to stop being black, and the engine to sound normal. But sometimes a few hours into running, it shows the same fault and sometimes even turns off.

Does this sound more like a faulty sender, or an actually high oil pressure?

If my oil pressure is actually high, what can I do about it?

 

[peapvp]

You can unscrew the Oil Pressure Transducer use a T connector and hook up a manual oil pressure gauge + transducer and see what is says.
By using a T, you can run the Genset. Without Transducer you should get a low oil pressure error and genset may not start.

 

[Guyfang]

My MEP-805B shows a high oil pressure fault while it's starting cold. If I keep cranking it while holding fault reset for about 30 seconds, it starts up and runs ok. This is the same amount of time it takes for the smoke to stop being black, and the engine to sound normal. But sometimes a few hours into running, it shows the same fault and sometimes even turns off.

Does this sound more like a faulty sender, or an actually high oil pressure?

If my oil pressure is actually high, what can I do about it?

Is this gen set new to you?
Have you serviced this gen set? Oil and filter?
How many hours on the meter?
Have you downloaded the TM's, and maybe read them a bit?

 

[diogenescreosote]

I've read some of the technical manual, but it doesn't seem to include a procedure for high oil pressure.

I changed the oil and filter on the generator when I bought it at auction 2 years ago. Used a NAPA brand filter, and delo 15W40 oil I haven't used it much until now, but it has always done this, even right after the oil change.

The meter has 1600 hours on it.

After the engine has started and I no longer get the warning about high oil pressure, I can take a voltmeter to the red wire coming out of the oil pressure sender, and it dances around between 3.1 and 3.3 volts, which would mean 52.5-57.5 psi.

 

[Guyfang]

Did it have this problem before the oil change?

 

[diogenescreosote]

Did it have this problem before the oil change?

I don't know because I didn't run it before the oil change. It was only started once before the oil change, and only for the purpose of warming up the oil to change it. I unfortunately am not the one who started it at that time so I didn't notice if there was a high pressure warning.

At the time I figured it was best to minimize running before an oil change, because I didn't know how long it had been sitting or when it was due for maintenance.

 

[Guyfang]

Go back and look at post #2. Like Peter wrote, get a T and hook up a manual oil gage. You need to be able to see, what it really is. The gage can lie, badly.

 

[diogenescreosote]

OK, I measured the oil pressure manually and I see zero evidence that the oil pressure actually gets near 100psi.

The warning is nonetheless irritating, as is the fact that it sometimes stops. What can I do to stop this?

 

[peapvp]

OK, I measured the oil pressure manually and I see zero evidence that the oil pressure actually gets near 100psi.

The warning is nonetheless irritating, as is the fact that it sometimes stops. What can I do to stop this?

The Oil Sensor, like on any car, has a tiny hole. Sometimes Dirt or old oil gets stuck in there, causing erratic oil pressure indications.
Two options:

1. Spray some Break Cleaner into the tiny opening and flush the sensor.

2. Buy a new Sensor

If the problem persists, then it is time to crawl through through your entire wiring harness and connectors.
Because of the relatively small voltages involved, even the slightest corrosion or moisture can cause issue.

 

[diogenescreosote]

The wiring coming out of the sensor, as well as into harness P7 (the white plastic 4pin harness right by the sensor) looks clean, intact, and free of corrosion.

Where exactly is A1/P6/H-J6? It looks like that's where the signal actually ends up, so I should inspect there too. I opened up the control panel in front, and I see a bunch of J[number] areas, but no A1/P6/H-J6. Any tips?

I will clean the sensor too and see what that does.

 

[peapvp]

The wiring coming out of the sensor, as well as into harness P7 (the white plastic 4pin harness right by the sensor) looks clean, intact, and free of corrosion.

Where exactly is A1/P6/H-J6? It looks like that's where the signal actually ends up, so I should inspect there too. I opened up the control panel in front, and I see a bunch of J[number] areas, but no A1/P6/H-J6. Any tips?

I will clean the sensor too and see what that does.

I hope you are into yoga. These are the amphenol / canon plugs on rear of PCB / cubicle

 

[Guyfang]

Ohhhhhhhhhhhhhhhhhhhhhh, they be a PITA.

 

[diogenescreosote]

I hope you are into yoga. These are the amphenol / canon plugs on rear of PCB / cubicle

I'm having trouble understanding this. "Amphenol / canon" refers to the circular kind of plug held on by a threaded collar, right?
I don't know what you mean by "rear of PCB / cubicle". I have the control panel down and I'm seeing all the beige stuff about speed regulation and AVR and voltage selection. Where do I go from here?

 

[Guyfang]

You need to take the top off, to see the back side of the card. Its a real tight spot.