New Holland 1920 injector question

GrantC · Apr 13, 2014

Hi everyone! I recently inherited an '87 1920 with 1200 hours on the clock. I'm catching up on all the deferred maintenance now; though the previous owners (my in-laws) changed the oil occasionally (not sure, as they didn't keep records), that's just about all they did! I have a copy of the FSM and Owner's Manual and I'm finding all the stuff that needs to be done and doing it.

The engine is running a bit rough (surging at idle, and occasionally missing at higher RPM.) Naturally I changed out the fuel filter where I found 1/8" of sludge in the bottom of the cup -- I suspect that might be part of the problem! New fuel filter helped a little, but it's still rough. Starts very easily, so it's getting fuel, but I don't think all of the injectors are working 100%.

This is especially likely since the injectors are supposed to be serviced every 600 hours, and these never have been. (The valves are supposed to be adjusted at the same interval, and that's never been done, either.) How can I tell? Because the factory paint on the fasteners has absolutely no marks! I decided to pull them and have them serviced. But there's this little problem...

I've removed the supply and overflow lines, taken off the clamps, throughly cleaned around the injectors and....they won't come out. According to what I can see in the FSM, they should pull right out -- but these sure won't! I even GENTLY pried upwards on the overflow elbow, and they won't budge. They're not loose at all.

Any tips on getting the things to slide out like they're supposed to?

-=[ Grant ]=-

TractorTech · Apr 15, 2014

Injector service interval is not as critical as adjusting the valves. At this point, it does look like they need to be addressed. Soak the injector bases in penetrating oil and let sit. Do not pull on the elbow. You will need a slide hammer to pull injectors, but you either need to adapt to the inlet line threads to pull from the top. Sometimes you can twist clockwise slightly to get the to loosen.
To diagnose which injector(s) are causing problems do the following. With the lines hooked up and the engine running, crack the injector high pressure line on each injector until the engine does not change or miss. When you crack the line open, you stop fuel supply to that injector and that cylinder will miss if the injector is good. If the injector is bad, the engine will not change or miss.

jones6780 · Apr 15, 2014

Do you mean the injectors are not threaded????

Coyote machine · Apr 15, 2014

If you crack the hi pressure lines on the injectors make sure to wear heavy gloves and goggles. Any spray of fuel at high pressure will penetrate skin, blind you, and if left untreated can cause need for amputation of the damaged tissue. This is no joke, high pressure diesel is deadly to human skin.
You can have the injectors cleaned and tested at a diesel repair facility to see if any are marginal. Often they can be re-calibrated as needed. Poorly functioning injectors/leaking injectors can do serious engine damage.
I'd pull the fuel tank and clean it thoroughly including adding biocide, and probably also replace the line from the tank all the way to the Injection Pump.

TractorTech · Apr 15, 2014

jones6780 said:
Do you mean the injectors are not threaded????

On the later 1920 injectors, they are threaded (1999 on), but the earlier engines (1987-1999) used injectors that slid into a bore and held with a clamp.

GrantC · Apr 21, 2014

Thanks for the feedback, folks!

It took some doing but they're all out! Two of them came out just by soaking and wiggling a little bit; the other two were stuck solid no matter how long they sat with penetrant (almost a week.) I ended up making a slide hammer as suggested and taking them out that way. Even then it required more than a little "tap"!

They were all pretty badly encrusted on the outlets, which partially explains the rough running. They're going into the injector service place tomorrow.

The first two seemed to be mostly locked in from the original factory paint, but the last two definitely had a little rust on the bodies. There will no doubt be some matching rust in the bores; what's the best way to get that cleaned out without the dust falling into the cylinder - or is it OK to let it?

-=[ Grant ]=-

Coyote machine · Apr 21, 2014

Best to not allow anything foreign into the cylinders. Best you might do is take a narrow air gun nozzle and pass it through the injector hole to where the end of the nozzle is in the cylinder below the end of the injector bore and blow compressed air into the cylinder to force any loose paint/rust/whathaveyou, up and out of the injector bore hole. Wear safety glasses, etc.