HELP !!!!!!

Thanks everyone for all your participation. Sounds like it's going to the dealer. I could do it but I just do not have the desire to go through all that. Thanks again.

I'm on a few rv forums and lots of truck forums and this is by far the best yet.

Your 4KY spec K does not have an oil pressure switch nor an oil level switch. The engine is splash lubricated so no oil pump and the oil level switch was done away with in a previous spec.
With the engine starting and not staying running, I would suspect the voltage regulator circuit or the brushes and slip rings/rotor assemblies. I would start with the regulator which is built into the control board. If you can, find the two wires that go to the brushes and slip rings. Apply 12 volt to these wires and if the unit stays running, you have a control board/regulator problem. If the unit still stops, place a multi-meter on the same wires and check the service manual for the correct ohmage reading to determine if the rotor or the brushes are bad.
Do not attermpt to remove the flywheel and repair unless you have the service manual. Lots of small parts and sequential disassembly procedures.

JimL

Onan 4000 Service Manual here. Page 10-2 has a diagram that shows the location of the oil level switch. The instructions on the same page say to remove the oil pan from the engine to gain access to the switch, which is inside the pan. Looks like quite a bit of dis-assembly is required to get to the oil pan.

Also the table on page 6-9 lists several reasons other than the oil level switch which would cause the engine to stop when the switch is released.

On page 6-6 is a wiring diagram that shows that pin 7 on the P1 connector from the control board is connected to the oil level switch. The other side of the switch connects to ground. A continuity test between pin 7 and ground will indicate whether the switch is open or closed. I assume that normal oil level closes the switch, but don't know for sure. If the oil is at the proper level per the dipstick, you can test the switch by draining the oil. If the switch is supposed to be closed for normal oil level, it should be open for low oil. On the other hand, if the switch is supposed to be open for normal oil level, it should be closed for low oil. If the switch doesn't change when the oil is drained, then the switch is defective.

Follow the trouble-shooting guide in the manual. Some Onans will not stay running if they don't generate output voltage (in my experience, this is more likely the cause than the oil pressure switch). If you post model (sorry I missed the model#) and serial number, one of the techs may be able to help.

I did thats where I got the file I have but like I said it shows it in the wiring diag but not the physical location. Cummins labor is $127 per hr so I want to do as much as I can myself. I'm handy with things just never worked on one of these. I built hot rods and restored muscle cars for many yrs so mechanics is not a problem just need to find the thing.

Thanks for the reply

Maybe google for a PDF of an installation manual or service manual?

Jim

msg sent j-d

I have a pdf. It shows it in the circuit but does not tell the location of the sensor.

What is the title of the manual or name of the pdf file. Often if you google the exact title you cn find the PDF.

Jim

Get a Service Manual. Some of the guys here have a link. I have it on file as .pdf so if you don't get the link, PM me with your email ID and I can email it to you as file attachment.