NH TN95FA Wont Run

Scout92 · Dec 29, 2017

So a little backstory, This tractor has a custom tree topper on the front of it, and while we were cutting some pomegranates around the Firebaugh, CA area, the engine decided to run away. Got it shut down before it blew up, but it ran really dirty afterwards.

Determined that the turbo oil seal had went out, and also that we had fuel in the case. We pulled injectors and found that one had a drip, and two were very weak on the springs. So 4 new injectors went in. (proper bleeding was done) however if I attempt to run the engine, every time afterwards I can get bubbles out of the fuel filter housing. So I guess I could be sucking air somewhere.

Since it was sitting in the yard, and it has a little over 3k hours on it, i decided to just make sure the valves were adjusted, I have a repair manual for this tractor so I followed the procedure listed in the book and buttoned it up. (I can post a picture of the procedure if that helps.)(Also ive checked this about 6 times now, so unless the book is wrong or someone put the cam in this engine wrong...)

Now for my issue:

Tractor wont start on its own. If you feed it some starting fluid at about half throttle, it runs but real crappy.. lots of white smoke. If you go back to idle, it dies.
I've been screwing with this for a week now, super frustrated. Anything that anyone can think of on this? I drove it to the spot it sits now and the engine was running pretty smooth except it was dirty. now it wont hardly run at all. Any new ideas would be appreciated. Thanks.

Phillip w · Dec 29, 2017

I'd put a new fuel filter on and check all you connections. You could possible be sucking air. I've changed fuel filters out in less than a week. I just changed one out today that is only about a month old. When they start acting funky, the fuel filter is the first thing I go after. The next thing is did it screw something up when it went into over speed. Detroit's used to go into over speed and they had an emergency shut down. I never seen one screw things up if you got it shut down. On those you had a trap door that shut the air down. Usually you just had to reset the trap.door. other that that, I'm running out of ideas.

Phillip w · Dec 29, 2017

Ps. Your air breather can make it smoke and run funky. Usually with the trouble your having, it Havre to be pretty bad. Fuel filter can look pretty good and they'll still run funky or not at all.

thepumpguysc · Dec 30, 2017

Loosen the fuel line that GOES INTO the front of the injection pump & spin the engine.
IF the lift pump/supply pump is working, fuel should squirt out pretty good.
I'm thinking lift pump is bad..
Pull the dipstick & see if its dumping fuel into the oil.
Have you loosened the lines going to the injectors to bleed the air out?

Scout92 · Jan 1, 2018

The lift pump is brand new; put it on about a week ago. I actually have the blow by return and air filter removed right now to eliminate those issues. I think what I'm going to go for next is a new fuel filter and replace all the vulcanized washer seal things that are on all of the banjo bolts for the fuel supply lines. Also the line going from the filter to the injection pump appears to have a kink in it and a twist right around the banjo bolt on the pump. So I think I'll replace all that and see where I'm at. Not today though, everyone is closed. :thumbdown:

Also, I have bled the lines directly from the injectors. I had it actually start once on its own, and it ran decent. And then I idled it down, and it died. The fact that it actually ran fine for like 10 seconds assures me I didn't somehow screw up the timing on the valves, and that this is just the worst time I've ever had chasing air leaks on a diesel.. haha

thepumpguysc · Jan 2, 2018

You could SLIGHTLY pressurize the fuel tank & LOOK for wet hoses/spots..
Heck, even go so far as to lightly dust the area w/ baby powder..??
In a lot of cases, a system WILL suck air & NOT leak fuel.

Sawyer Rob · Jan 2, 2018

thepumpguysc said:
You could SLIGHTLY pressurize the fuel tank & LOOK for wet hoses/spots..
Heck, even go so far as to lightly dust the area w/ baby powder..??
In a lot of cases, a system WILL suck air & NOT leak fuel.

I've done the above and it works quite good, it's a good idea... I use my compressor nozzle in the fuel tank with a rag around it.

In fact, I do it every time I change fuel filters, to bleed the air out.

To me, it sounds like it IS getting air from someplace and as I've already seen one of those with a bad fuel line, it would make me look at that one closely.

SR

Scout92 · Jan 4, 2018

Got it running.. Ended up being air in the fuel. There are these vulcanized washers on each of the connections. They were fine, until I took them off the first time. Going back on they wouldn't seal. $35 to replace them all from CNH. A quick bleed at the fuel filter and it fired right up.

Also, on this particular tractor, if you take off the line going from the tank to the lift pump, the connection is below the fuel tank, so gravity keeps that line pretty well air-free.

Thanks guys!