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Need Assistance Identifying Onan Diesel Model

sl33k3r

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I purchased an diesel engine not knowing what I was buying because I figured it was a bargain. I thought I could search online once I found the block number (3381), I would find the model, manual and all would be dandy. Not so! I searched and cannot find the engine model. I tried searching on casting numbers of a couple parts as well with no luck. I cannot even search on the fuel filter since the numbers are not clear at all. The engine does not have a tapered shaft. Does anyone here know what I have or where I could look?
 

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Chainbreaker

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And unfortunately with a "PSU" injection pump (not Ambac M50). If the IJ pump needs parts its going to be difficult to find them.

I have an engine service manual that covers the DJE that I will attach. Hope it helps!

Edit: BTW, this is a very good resource when working on the Military version engine for the MEP-003a/-002a's as it shows a lot of detail procedures and tips and tools that you won't find anywhere else. You just have to keep in mind the differences that the military version has.
 

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sl33k3r

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Specifically its an Onan DJE 6.0
Thank you very much! I was thinking it was...poked around after posting and it looked similar. At least now I can purchase filters for fuel, oil and air. It is really odd though that the output shaft is not a tapered shaft and that it is huge for a smaller engine.
 

sl33k3r

New member
25
5
3
Location
Potsdam/NY
And unfortunately with a "PSU" injection pump (not Ambac M50). If the IJ pump needs parts its going to be difficult to find them.

I have an engine service manual that covers the DJE that I will attach. Hope it helps!

Edit: BTW, this is a very good resource when working on the Military version engine for the MEP-003a/-002a's as it shows a lot of detail procedures and tips and tools that you won't find anywhere else. You just have to keep in mind the differences that the military version has.
Thank you for your assistance. The engine has sat for quite some time. The previous owner tried to start it but there was no ignition. There was fuel in the return line so something was pumping, maybe not enough to get the proper pressure to the injectors. The manual will certainly help.
 

sl33k3r

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Potsdam/NY
Looking through the service manual at the injector pump, there is a difference between the pumps. for the DJB and DJE. The DJE has the injector lines side by side at the 3 and 9 o'clock positions on a flat plate and the DJB has the injector lines at the 2 and 8 o'clock positions on a conical casting with a nut between the injector lines. So, I have to believe, with good intentions, DieselAddict was slightly mistaken on his identification? He got me in the right church, just the wrong pew...so to speak. Also, I had forgotten that there may have been a low oil pressure shut-off switch. The engine may not have started for the previous owner if the oil had all leaked out through a loose drain cap. I do not recall if there was oil on the floor where the engine sat when I originally looked at it.

I'm going to go through the service manual first. Then I'll change all the oil and filters and hope for the best.

A few years ago I had a MEP-002a. I liked it but there came a time when I needed money more than the generator. I now have a MEP-802a. If I remember correctly, the 002a was positive ground. Would this be positive ground as well? If so, the previous owner likely connected the battery in reverse. The engine would crank backwards and would not start. Am I correct in my assumption?
 

Ray70

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Hello, you are correct, that motor is a DJB series.
The 002 is a negative ground 24V system. That motor is probably as well.
If it is positive ground the starter will NOT spin backwards.... sort of. The starter motor will physically turn backwards but it will not engage the drive gear because the drive gear will "freewheel" in the opposite direction so although the starter will spin, it will most likely not crank the motor in reverse because it can not engage the drive gear backwards.

Also, the fuel in the return line does not mean the IP is working, the mechanical fuel pump will push fuel throughout the system, the IP only sends high pressure fuel up to the injectors.

Being you have a PSU injection pump that has sat a long time I would almost bet it is currently frozen and quite possibly the plunger is broken if the previous owner tried to start it while the pump was frozen.

If it is currently stuck and you attempt to start it you will surely break the plunger, for which there is NO replacement available. You would need to replace the entire pump with an Ambac M50.

Try moving the throttle linkage up. If it does not move freely, that is a sure sign your pump is currently stuck and DO NOT attempt to crank it over!
Either remove the pump and clean / rebuild it or at least follow the steps in the Sticky ( fill with acetone and soak etc. ) to try to free it up before cranking it over.
 

sl33k3r

New member
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Potsdam/NY
Hello, you are correct, that motor is a DJB series.
The 002 is a negative ground 24V system. That motor is probably as well.
If it is positive ground the starter will NOT spin backwards.... sort of. The starter motor will physically turn backwards but it will not engage the drive gear because the drive gear will "freewheel" in the opposite direction so although the starter will spin, it will most likely not crank the motor in reverse because it can not engage the drive gear backwards.

Also, the fuel in the return line does not mean the IP is working, the mechanical fuel pump will push fuel throughout the system, the IP only sends high pressure fuel up to the injectors.

Being you have a PSU injection pump that has sat a long time I would almost bet it is currently frozen and quite possibly the plunger is broken if the previous owner tried to start it while the pump was frozen.

If it is currently stuck and you attempt to start it you will surely break the plunger, for which there is NO replacement available. You would need to replace the entire pump with an Ambac M50.

Try moving the throttle linkage up. If it does not move freely, that is a sure sign your pump is currently stuck and DO NOT attempt to crank it over!
Either remove the pump and clean / rebuild it or at least follow the steps in the Sticky ( fill with acetone and soak etc. ) to try to free it up before cranking it over.
I know the previous owner attempted to start it. There was fuel on the floor and he stated it did pop when starting fluid (YUCK) was shot into the intake.

My 002 was positive ground. I am sure of it because I remember it going against everything I knew (at the time) to hook up the two batteries. I remember turning my head away as I placed the last positive cable on the battery post. Maybe it wasn't a 002 but I know it was a 5kw 2 cylinder air cooled Onan. The oil pressure gauge was located in the same place and it did not work. Neither did the charging system, but I think that was because the fuse was blown because the batteries had been connected "negative" ground by someone else before I got it. The one way clutch on the starter drive would have not turned over the engine if it were spinning in reverse. I had an error in my thinking before when I made the question.

I hope the pump plunger is not broken. I will follow your advice before I try to turn it over, though.

Thank you
 

Ray70

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Definitely was not an 002 if it was Positive ground, although to some, the 002 battery cables may appear to be positive ground because the negative goes to the body of the starter. However the post on the starter's body is the ground.
The positive battery cable goes to the solenoid up on top of the starter which is almost impossible to see, so I bet it was Negative ground and you thought it was Positive because you saw the negative going to the starter.
But 100% absolutely positive there is no such animal as a Positive ground 002.

Good luck and keep us posted on your progress!
 

sl33k3r

New member
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5
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Location
Potsdam/NY
Definitely was not an 002 if it was Positive ground, although to some, the 002 battery cables may appear to be positive ground because the negative goes to the body of the starter. However the post on the starter's body is the ground.
The positive battery cable goes to the solenoid up on top of the starter which is almost impossible to see, so I bet it was Negative ground and you thought it was Positive because you saw the negative going to the starter.
But 100% absolutely positive there is no such animal as a Positive ground 002.

Good luck and keep us posted on your progress!
Noted! And will do!

I removed the engine from the back of my truck. After unhooking it from the tractor, I checked the oil. The level is slightly below full and pretty clean. I did, by hand, pump the fuel pump and fuel did push out the return. I also, checked the throttle linkage for freedom of movement. There is no resistance. Possibly, there is a fault in the circuit to actuate the solenoid to turn on the fuel. I will check the resistance of the solenoid and circuit for continuity later when I connect a battery. Speaking of battery, there is a diagram , as seen in the images above of the starter side, indicating it is negative ground.

Thank you all!
 
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