Nh 575e fuel problem

[CANNONMAN1]

This has been one of the best units I have ever owned but is now giving me fits. It seemed as though it was running out of fuel when working it. I replaced the fuel pump without any change. It will idle forever but when put under load it will start out great and slowly lose power until it quits. Let it sit with either key on (so fuel pump runs) or off it will start right up and run for 30 seconds or so. Thought I got a bad fuel pump so I replaced again with same results. Today I thought maybe there is something in the line from tank. Blew it back into tank, same results. I put a separate electric fuel pump with a new line from tank to glass bowl forcing fuel into it before it goes into factory fuel pump. No difference same problem. Do I have a weak or failing injection pump? This would be costly and I want to make sure I am not missing something. All filters are new and clean. Air cleaner clean.
Other problem I have is I am at a lodge @ 10,000 ft. and an hour away with no equipment to trailer it to a shop. They get a fortune to haul from up here to shop in Grand Junction. Any ideas gentlemen? Thanks in advance.

 

[fpgm04]

Here are a couple thoughts, I will let others on more qualified on this forum to answer your injection pump question.

Have you checked the vent on your fuel tank? I have seen the fuel tank vent get clogged and ultimately restrict fuel flow. I would recommend the next time the vehicle quits, you loosen the fuel cap and see if you have a lot of vacuum which would certainly point you to a fuel vent issue. I don't know if NH has a vent in the cap or in the tank, but either way they get clogged.

Just a thought as you are apparently in the mountains, and assuming outside to put the vehicle under load, is your fuel partially gelling in cold weather?

 

[Delmer]

Could you post a pic of the fuel pump and the injection pump? or just describe them. Does the fuel pump have a primer lever on it? if it does you can diagnose the issue with that lever fairly well. If no primer lever, I'd tee into the line going into the injection pump and run a line to the cab so you can tell if it's the supply or injection pump.

Never seen it myself, but apparently some pumps have a flex ring that disintigrates and clogs the return fitting on top of the pump. If you find rubber/plastic bits in the fitting then it's time for a new pump. Also couldn't hurt to remove the inlet fitting to see if there's a clogged screen there.

Generic advice, may not apply to any backhoe.

 

[CANNONMAN1]

One of my first thoughts was a clogged vent. Running with cap off makes no difference. No gelling as I run blended fuel year round. Good thoughts though. Thanks

 

[CANNONMAN1]

Never thought about blowing out return line. Will try that in the morning. I also read on here about the "flex ring" clogging up things. The pump is electric and does not have the conventional pump lever, that is why I try putting another electric pump before the factory one with the hose running out of the top of tank thru fuel cap opening. Thanks

 

[thepumpguysc]

What you have on your machine is a "Delphi" 310 injection pump.
More than likely it has a clogged inlet filter screen under the big nut at the inj. pump inlet.
Remove the big nut, hold down the big spring with your finger and shoot some air into it to remove the fuel so you can see better.., remove the big spring, remove the pressure adjuster..
You'll see the plastic filter on the sides of the bore.. its round and fits over the regulating sleeve..
HOLD DOWN THE REGULATING SLEEVE with a small screwdriver and pick out the filter with a 90* scribe.. blow it off and reinstall.

 

[CANNONMAN1]

Pump Guy, Can't find a tag on pump to see what kind it is. I took off inlet tube and took off big nut. Don't see any big spring. It looks like a sleeve with notches on the top. Kind of looks like a castle nut. Doesn't seem to turn but I can push it down slightly. Thought maybe this the pressure adjuster but there is no spring you speak of. It does look like there is a rubber washer around the sleeve with notches. Is this a Delphi 310 pump or something else? Does the notched sleeve just pull up out of there? Where might I find a tag or plate telling me what I have? Appreciate all the help guys.

 

[thepumpguysc]

OOPS.. your correct.. that doesn't have a spring on top.. its on the bottom..
just try to grab the filter with a sharp 90* scribe and pull up.

 

[CANNONMAN1]

PumpGuy, I was not able to get that piece out of the center. Put big nut back in and got to looking and blowing out hoses and found a glob of who knows what right where the supply line goes into the banjo fitting at the fuel bowl. Blew it out and blew out all other hoses and low and behold we have ignition. Full rpm and running perfect again. Don't know why by now not to over think things, that it is usually the simple things that are causing the problems. Thanks for your help. These forums are great and just saved me $3-$500 if not more!

 

[thepumpguysc]

Your welcome.. It helps to talk things thru and get a fresh pair of eyes on a problem..
Last week I was called to work on a BRAND NEW 2 million $ yacht.. It had a fuel system problem and none of the builders could solve it..it was a basic 6 cyl. Simms pump..
After talking w the owner and then the builder and then the mechanic, I solved the problem in 15 minutes.. they've been fighting it for 2 weeks..
The owner didn't switch the gate valve when he switched from port to starb. fuel tanks.. he had to actually turn ON the tank before switching..
Hope you solved your problem..