Diesel injectors just will not fire after filter plugging/swap

[rectifier]

My IH B275 tractor suddenly died 2 days ago at half throttle. -30C outside. No misfiring or sputtering down, just a sudden stop. Very poor flow through fuel filter, found water ice in the bowl and likely in the filter as well. The filter was old and dirty, so I changed it.

This is a CAV rotary injection pump by the way.

Changed filter, prefilled canister with clean diesel, followed entire bleed procedure as well as I can with 1 man. Good flow through filter, good flow out of bleed screws on pump, and when cranked with lines cracked, plenty of flow to injectors. No bubbles apparent in anything. If I crack the return lines on the injectors, I get flow out of them when cranking. I have put more than enough fuel through the injector lines to flush them out fully.

However not even a puff from the exhaust. It's still -28C out, but the motor is heated with a 1500W circulating heater and pump, and I let it sit for 4 hours at 110F coolant temperature. The heads and injectors are warm to the touch, so no wax should be present. It turns over plenty fast, it will usually fire even if it barely turns over. Can anyone tell me, what am I doing wrong here!? I need this machine running yesterday (literally, I cannot feed hay without it) and have been working on it all day in the arctic cold.

 

[RNeumann]

You didn't mention changing all the fuel in the tank. If you had ice in the fuel bowl I'm wondering if you have more water in the tank?

 

[Redneck in training]

I am not fuel system expert. I answered to keep your post on top. Looks like your fuel system is OK but there still could be water in the injector lines. crack them on injectors and bleed it some more. Check if the mechanical kill lever is in correct position. Also check air filter for restriction.

 

[rectifier]

I did change the fuel a week earlier, it was summer fuel that plugged the strainer on me but not the filter. I suspect some made it to the filter and that's what plugged it yesterday. Now the tank contains winter fuel with Howe's Diesel Treat at winter rates.

There is no water or crystal visible in the glass water trap/strainer bowl below the tank. I hadn't drained this filter bowl in forever so the ice was probably an accumulation of several years of moisture (embarrassing, yes)

The kill lever has to be open to bleed the injectors, so it is definitely so. And the motor is acting as an effective air pump, no restriction or apparent valve issues.

I just read about pulling the glows to release the compression as an aid to final bleeding. Also that way I can see if any fuel is making it through the injectors at all. I'll try that tomorrow. I've had to bleed this machine before and it is always a huge pain - but it has never been this bad to me. I've also never bled it at -28, though.

 

[Rock knocker]

I think it has to do with -28

 

[RNeumann]

I also read a post here about using a heat gun to blow hot air into the intake.....one more idea to warm things up. An easy try before pulling glow plugs.

Keep us posted. Sorry it's -28

 

[rectifier]

Meh, I'm used to it being -28. It hadn't been above -20 for 2 weeks up until today, when the weather finally broke and I'm smiling in the snow at -4.

It runs now, but I couldn't tell you why. The answer was just to keep on keepin' on until it fired, I suppose. I can tell you what was wrong with it - many things.

- first off, the primer lever has long been broken off before I got the machine. I have to bleed by cranking. In the cold this is just stupid, hard on the battery and the machine, so I pulled the lift pump off the side of the motor so I could pump it manually. This was a huge help.

- I had used the wrong bleed screw on the filter to get started. I bled the clean side, top and center of the filter. Should have bled the dirty side (crack the return line), this one has way more air in it. The clean side appeared to bleed clean, but maybe small bubbles were sneaking through.
- bled this port for 15 minutes and still getting gobs of air. Crack downstream of fuel pump. It is pumping bubbly fuel.
- when reinstalling the separator bowl, it was so cold the gasket didn't deform, allowing air to be sucked in. But why would it pull air through here, the tank is much less restriction? Unless...
- tank pickup is waxed AGAIN (or still waxed), so it pulls through the gasket instead of from the tank. Heat the petcock until it flows well.
- also, the screen in the separator is waxed and doesn't look like it because it's wet. Burnt that off with the heat gun. Heat the gasket until it's nice and soft, then reinstall.
- not drawing air anymore, but also not putting out much fuel. Let's check the lift pump.
- the screen in the lift pump is waxed and there is also a ton of gunk in the pump, piled up before the screen. Screen did its job! Carb cleaner and rags and flush it with diesel. Burn the screen off with the heat gun.
- NOW we are getting some good flow of clean fuel. Bleed the filter properly. Bleed the injection pump, rotate motor, repeat 3x. Bleed the injector lines.
- **** it, it still won't even puff a ghost. What could be wrong.

- time to step it up a notch. Pull an injector. Don't worry guys, I know injectors are both dangerous and fragile, I've done this before, I rebuilt the whole top end of this tractor.
- flip the injector out, bleed line and hook it up, sure enough it is not popping. What am I going to do.
- Ok, what's left to try. Let's disassemble the injector. This I have NOT done before but I have a procedure in the shop manual and a long history with fixing tiny, sensitive stuff.
- there is gunk in the injector. A bit of scuffing on the side of the pintle, fortunately not on any working surfaces. Huh. Didn't expect that. Clean it up well with carb cleaner. Wash it all in diesel.
- reinstall injector. Line up fuel line. Flip the starter to purge that line in case anything got on the end.
- Unexpectedly, a tiny puff of smoke comes out the exhaust. Oh boy! But wait. I haven't even connected the injector I cleaned up. Oh well, let's run with it.
- loosely connect the injector nut, I don't want to disturb this fragile state. Glow plugs on. Crank until it pops and sputters into life. Tighten the line on this injector and it smooths up and runs perfectly. Why? You tell me!


So what did we learn from this terrible ordeal?
- NO SUMMER FUEL IN DECEMBER, even if it's above freezing, and there is additive in the fuel. It could be cold tomorrow and stay that way. This is what got me into this mess.
- in a filter plugging incident, check EVERY filter and screen in the machine, even the ones you don't know are there.
- always warm rubber seals before installing in a cold environment.
- I need a 12V fuel/filter preheater. Maybe a plug in fuel tank heater even.
- I need to pull and clean the rest of my injectors on a nice day. Fairly soon, I think.
- I could use a secondary filter or at least should start using a filter funnel. Apparently our fuel is full of junk.
- Apparently chickens are tougher than they look. Even if they get loose and wander off, they can eat snow and survive 2 weeks below -20 out in the bin yard eating spilled grain. They get enough shelter hiding under broken down tractors.

 

[RNeumann]

Glad it's running! I will always use some type of fuel additive after reading this post! It will be interesting to see if heat in the pump/filter area helps. Seems like their are so many areas that are subject to freezing fuel.

It's not clear from your post if you cleaned one injector or all of them? From what you are saying it sounds like you cleaned one and the rest cleared with heat?

 

[rectifier]

I cleaned one, but it made no difference. When I reinstalled it, I had not even hooked it up - the other injectors miraculously started on their own. I then tightened the fitting on the cleaned injector and it came to life as well.

The injector gunk was not wax and wouldn't have melted or even passed the nozzle - it was thick, solid, black gunk. Not what you want to find in your injectors, and you would not want to try to dissolve it with injector cleaner! If any came free it would have plugged the nozzle immediately.

I suspect the miracle had something to do with bleeding, of course. I had that injector line 100% disconnected as well as the common return line. Could this have changed something in the flow and allowed the last tiny amount of air to get out? It's hard to know... I hate bleeding diesels.

 

[RNeumann]

Glad it's running!