Dirtleg
Member
As I get time and money to go through my new to me MF390 I have been doing the little routine maintenance items. This week was the fuel filter. The old one was leaking a little and I felt I just needed to change it. So I did. After I changed it I used the primer lever on the lift pump to bleed the air out of the lines. Or so I thought.
Now I am not new to diesels and have redone the injection system on a truck I own a couple of times so far. On that truck it is a pain to bleed the system because you have to crank the engine to work the lift pump. So I thought it would be simple to get the air out of the lines since the lift pump has a primer lever.
Initially it seemed to work just fine and once it seemed the lines were clear I started the tractor. It ran maybe 3 seconds and died. Obviously I didn't finish the job. So I kept pumping on the lever. I pumped it 100 times and tried to start it. Nothing. 100 more times nothing. So at this point I broke out the ether figuring it just needed a little bump to get it going. Nothing.
Well now it was time to actually figure out what was the issue. I checked a few things until I realized that at some point the lift pump primer lever wasn't pushing any fuel into the system anymore. I was disappointed as the lift pump is only a month old. The original lasted 23 years.
I decided to remove the lift pump and see if I could figure out why it stopped pumping. My tractor doesn't have a fuel shutoff betweeen the tank and lift pump. This is now on my list of modifications. As such I had to remove the line near the tank and plug it.
Once the pump was off I opened it up and checked for anything wrong. Everything looked fine except ther was a large amount of sediment on top of the inlet screen in the pump. Glad I found that before it got any worse. I put the pump back on and no difference.
This time I left the pump on the tractor and just removed the section above the pump diaphragm. After cleaning and inspecting the check valves I was about to reassemble it when the cause of the entire issue hit me in the face like a rock.:confused2:
I noticed the diaphragm was in the recessed position. Apparently the engine had stopped so that the pump lever/lobe were in the fully compressed position. No amount of pumping the lever on the pump was moving the diaphragm at all. Yes I felt extremely dumb at that moment. I cranked the engine over to reorient the pump position and noticed the engine stopped in the same place. I tried it again with the same result. This is just the spot where my engine likes to stop rotating. I bumped it a little until it was near the top of its stroke and reassembled the pump.
At last success was mine. Now I was able to prime the system and get it started like I was expecting to in the first place.
Just a small lesson learned here I thought I might share with ya'll.
Now I am not new to diesels and have redone the injection system on a truck I own a couple of times so far. On that truck it is a pain to bleed the system because you have to crank the engine to work the lift pump. So I thought it would be simple to get the air out of the lines since the lift pump has a primer lever.
Initially it seemed to work just fine and once it seemed the lines were clear I started the tractor. It ran maybe 3 seconds and died. Obviously I didn't finish the job. So I kept pumping on the lever. I pumped it 100 times and tried to start it. Nothing. 100 more times nothing. So at this point I broke out the ether figuring it just needed a little bump to get it going. Nothing.
Well now it was time to actually figure out what was the issue. I checked a few things until I realized that at some point the lift pump primer lever wasn't pushing any fuel into the system anymore. I was disappointed as the lift pump is only a month old. The original lasted 23 years.
I decided to remove the lift pump and see if I could figure out why it stopped pumping. My tractor doesn't have a fuel shutoff betweeen the tank and lift pump. This is now on my list of modifications. As such I had to remove the line near the tank and plug it.
Once the pump was off I opened it up and checked for anything wrong. Everything looked fine except ther was a large amount of sediment on top of the inlet screen in the pump. Glad I found that before it got any worse. I put the pump back on and no difference.
This time I left the pump on the tractor and just removed the section above the pump diaphragm. After cleaning and inspecting the check valves I was about to reassemble it when the cause of the entire issue hit me in the face like a rock.:confused2:
I noticed the diaphragm was in the recessed position. Apparently the engine had stopped so that the pump lever/lobe were in the fully compressed position. No amount of pumping the lever on the pump was moving the diaphragm at all. Yes I felt extremely dumb at that moment. I cranked the engine over to reorient the pump position and noticed the engine stopped in the same place. I tried it again with the same result. This is just the spot where my engine likes to stop rotating. I bumped it a little until it was near the top of its stroke and reassembled the pump.
At last success was mine. Now I was able to prime the system and get it started like I was expecting to in the first place.
Just a small lesson learned here I thought I might share with ya'll.
