Case 400 Fuel Pressure

[Case35]

1955 Case 400 diesel. Starts up and smokes for a minute or so, runs good and has good fuel pressure. After about 10 minutes, when it gets warm it loses all fuel pressure. It continues to run good while just riding around, but while being worked yesterday it did finally quit. Unhooked the dyno, pulled it a few feet and it fired up and ran fine.

If it sits for more than a day or so, it absolutely refuses to start on the battery, but if you pull it a couple feet it starts fine. This tractor had sat since the mid 1980s until I got it running a couple months ago. It has brand new filters, new pressure gauge, new rubber line grommets, etc. There are no external leaks. This still has the original PSB pump. I am thinking I have a worn lift/transfer pump. Does anyone have any ideas?

 

[tomturkey]

Dieseltech a regular on this site is my goto guy about my 56 400 Diesel. gobble

 

[Case Nutty 1660]

You are losing prime,, you have a air leak some where or you have a plugged/restriped line coming from the tank to the filters, I see you state no leaks,, I would check the shutoff valve for debris, I have also had to unhook the fuel line at the valve and at the filter base and blow through them to get the debris out

 

[Case35]

You are losing prime,, you have a air leak some where or you have a plugged/restriped line coming from the tank to the filters, I see you state no leaks,, I would check the shutoff valve for debris, I have also had to unhook the fuel line at the valve and at the filter base and blow through them to get the debris out

Thanks for the idea! I had the tank and valve off and both were cleaned out. I also blew through all the lines when installing new rubber grommets.

I agree that I am losing prime, which is my starting issue. Why do I get a bunch of smoke for the first few minutes after starting, before it clears up? Why am I losing fuel pressure on the gage once the tractor warms up? It continues to run fine as long as I am not working it hard. Am I wrong to think that the pressure reading for the gage is before the lift/transfer pump?

My crankcase oil level is reading about a quart-ish high on the dipstick, but it does not smell like diesel. From everything I have found, when the lift pump seal leaks, it fills the crankcase in a hurry.

Prior to being deep into the engine on this tractor, I have very little experience with diesels. @Dieseltech?

 

[tomturkey]

well I'm not much a mechanic, most of what I have learned was from this site and you tube tutorials. But I'll take a stab at a couple of your question. Ofcourse I could be wrong so don't rip on me for trying to be helpful. Smoke on start-up---diesel engine relies on combustion chamber pressure and fuel. engine cranks over and compression chamber gets warmer all the while fuel is being injected in, finally the heat and pressure are good and the explosion occurs, you have excess fuel in the chamber so you have plenty of smoke until things get a bit hotter and the fuel air pressure and heat even out and most of the smoke goes away. Thats just this rookies explanation for smoke on start up. Losing fuel pressure as the tractor reaches operating temp--fuel cannot keep up with the demand of the engine, injection pump cannot push what it is not recieving the whole fuel system is pressurized. as said a restriction somewhere. When I was getting fuel into my oil, I removed the pump and sent it away to dieseltech for repair. With parts for those pumps being not available it was nothing I wanted to screw up. Although I was told later, if you can take the pump off and put it back on and make it run I could have repaired the pump. A mans gotta know his limitations . hope my long winded explanations are helpful, I'm definitely no expert not even close.....gobble

 

[Case Nutty 1660]

Thanks for the idea! I had the tank and valve off and both were cleaned out. I also blew through all the lines when installing new rubber grommets.

I agree that I am losing prime, which is my starting issue. Why do I get a bunch of smoke for the first few minutes after starting, before it clears up? Why am I losing fuel pressure on the gage once the tractor warms up? It continues to run fine as long as I am not working it hard. Am I wrong to think that the pressure reading for the gage is before the lift/transfer pump?

My crankcase oil level is reading about a quart-ish high on the dipstick, but it does not smell like diesel. From everything I have found, when the lift pump seal leaks, it fills the crankcase in a hurry.

Prior to being deep into the engine on this tractor, I have very little experience with diesels. @Dieseltech?

To me if you get some smoke at start that is not "normal" it will be due to air entry in the fuel system, just a educated guess though, I forgot to add in I have seen "floaters" in the tank, which will float up when the engine is off but get pulled down to the outlet when running, I have also seen air leaks at the supply pump

 

[GBman]

1955 Case 400 diesel. Starts up and smokes for a minute or so, runs good and has good fuel pressure. After about 10 minutes, when it gets warm it loses all fuel pressure. It continues to run good while just riding around, but while being worked yesterday it did finally quit. Unhooked the dyno, pulled it a few feet and it fired up and ran fine.

If it sits for more than a day or so, it absolutely refuses to start on the battery, but if you pull it a couple feet it starts fine. This tractor had sat since the mid 1980s until I got it running a couple months ago. It has brand new filters, new pressure gauge, new rubber line grommets, etc. There are no external leaks. This still has the original PSB pump. I am thinking I have a worn lift/transfer pump. Does anyone have any ideas?

Hi, If you look back recently I asked about replacing the seal in the PSB on the driven shaft of fuel pump. I had fuel in my crankcase too. It sounds like that is happening with yours. May be other things too but that is an inexpensive fix and easy too. David and John were very helpful, just look at that post and you'll get all diagram and all. I ordered the seal from John Saeli and had it in quick.

 

[GBman]

This is the diagram that David shared. You can see the seal (39).