Help bleeding diesel injection

[cobbkevin]

First time poster, long time listener!
I hope this isn't too long-winded, but I'm trying to give some background information. The tractor is an older Ford 3500 Industrial which is my first diesel engine. It was originally my wife's grandfather's machine. My FIL drove it to our house a couple of weeks ago (it had a lot of smoke and seemed running a little rough). The next day he started it and demonstrated the FEL and the back hydraulics to me (but he used starting fluid). Apparently SF has been used for recent memory.
The next day I tried to start it and nothing. It cranks but doesn't start. He came over and confirmed that it was in neutral, kill switch position, etc but he couldn't get it to start either. A shop mechanic came out and went through a quick trouble-shooting. He opened a bleed screw at the fuel filters and got nothing. He indicated that the filters must be dirty. I ordered new ones (and a shop manual). One filter was actually a sight glass / sediment bowl and was pack full of mud! These haven't been opened for 15+ years. I've totally cleaned up the bowl and installed a new filter element in the other side.
I've went through the process in the manual for bleeding (I think)! I've opened the top bleeder screws on the filter cover and they both flow freely. When I open the bleed screw on the side of the CAV injection pump and crank the engine it squirts about a foot stream. However, when I opened an injector line it only drips when I crank the engine. I then opened the hard lines (only 2 - I can't reach the back one) at the back of the pump up to the injectors. They only drip when the engine is cranked. I don't see any other bleed locations in the manual. Could the pump have gone bad from dirty fuel?
I don't think I've missed anything.
How does the kill switch circuit work? Does it stop fuel inside the pump from reaching the injector lines? If so, could it be stuck? I've manipulated it manually at the pump and it 'feels' like it twists but I don't have anything to compare it to.
Any thoughts would be greatly appreciated!

A diesel newbie,
Kevin

 

[john_bud]

Kevin,

Well, you sound like you have done all the right generic things. (always good to hear). I can't give any specific CAV pump input, just more generic stuff.

Yes, the pump can go bad from dirt. Easily.

As you may know, SF is bad stuff. It works in the short term, but can blow the ring lands right off the pistons. I just rebuilt a SF queen with 2/4 pistons with blown lands.

You may have a tired engine in the tractor. Do you have access to a diesel compression tester? Your shop mech may have the stuff. It would be good to know if the smoke and rough running was from a bad engine or just clogged fuel filter.

When you cracked the lines, did you have the "throttle" -- really the fuel control lever or some such technical name -- put in the middle. So it would run at about 1/2 of rated RPM? How full is the tank? A full tank will help the system bleed faster. How long did you crank the engine over? It may need 4 - 10 sessions of 15 seconds of cranking followed by 2-4 min of starter cool off time to get fully rid of air. Don't be afraid to have a charger on while doing this, your battery will like that.

good luck!

jb

 

[XANDROS_user]

JB, In response to your response may I ask a question: Is it feasible to attach a hand held mechanical vaccum pump (as used in bleeding brake systems) to purge /syphon the fuel to the injectors? Are there too many gates/switches/obstructions? Is it feasible to attach open hoses to injector lines? Saving the wear and tear on the battery and starter. I dunno. Just asking.....

 

[RobJ]

No I don't think it's worth all the trouble to put a bleeder system on the injector lines. If the lines are completly drained, it still only takes a half minute of turning to fill them up.

Kevin...didn't you say the tractor will run once started with SF? What color smoke? Was it still running rough at a high idle? Say max throttle? When cranking you should get a nice little spirt from the injector line because the governer has the throttle in max position. After it has run for a few minutes can you shut it off and crank it right back up without SF? Also while running pull one of the injector lines and see what sort of fuel is coming out.

Sounds like the pump will build up enough pressure when the motor is turning fast enough. Cranking is not fast enough. May be time to pulll the pump and have it tested on a bench.

Good Luck,
Rob

 

[higgy]

Depending on the engine and its design SF is not so bad. For example my JD 4020 has a SF distributor built into the system for use under 30 degrees, however, it does not have glow plugs.

on the injectors there are several things that may be incorrect/need tweaking.

When replacing the filters and cleaning the bowl, were you certain that you did not introduce contamination? I would think the answer is yes.

The pump that the individual lines are connected to is the high pressure pump that supplies fuel to the injector/nozzle, there is a difference. On a nozzle system the high pressure pump supplies the pressure to crack off the nozzle and introduce the fuel into the cylinder. With an injector it is supplied to the injector at a pressure less than required for opening the injector tip and a mechanical arm usually driven from the camshaft presses on the injector which is also a small pump and squirts the fuel into the cylinder.

The nozzle type is more prone to air than an injector.

I am assuming that you have injectors. The place to bleed the injectors is where the hard lines meet the injector, not at the pump. I normally loosen half of the injectors on the engine at the joint to the hard line. Do not back the coupling off so far as to be disconnected, just loose.

Roll the engine over, when you start to see fuel dripping from the connectors tighten them up, if you can get someone to continue rolling the engine while you do this. Many times the engine will start while you are tightening the lines up, or before you get them all tight, that’s ok.

When you get ready to fix this long term as stated before you will want to have the fuel pump bench tested, the other thing to do is pull the injectors and have them tested as well. Injectors get old as well and stop providing the proper pressure for the fuel when injected, when this happens the fuel will not atomize correctly. This can lead to black smoke, hard starting and if bad enough engine damage.

 

[patrick_g]

If you do get the engine running again, you still want to bleed each injector one at a time. Only loosen the connection at the far end of the line away from the high pressure (sometimes called the distributor pump) and only loosen it just enough for a small fuel flow. Don't get in too much of a hurry. Let a little fuel run out to ensure little or no air left behind. Tighten that connection and go to the next. Do them all.

Often there is a place to bleed air from the fuel system at the highest point in the fuel system (where air would naturaly accumulate) On my Ford there was a Schrader valve in the fuel system next to the filter before the high pressure pump. I used a Schrader fitting and plastic hose from a can of "Instant Spare" to make bleeding easy.

With the engine running I screwed the hose's fitting onto the Schrader valve and uncrewed it when all the air was gone and when just fuel with no air bubbles was being expelled into my tomato can. The fuel was clean so I poured it back into the tank.

There are other problems possible with worn out diesels. It has happened that a worn out diesel had so much blow by that oil fumes from the crankcase would make it into the combustion chamber and be burned as fuel. No harm no foul??? Well you can't shut the engine off or control its speed with the throttle. Kill switches don't help and turning off a fuel petcock will not help. The engine is getting air and fuel and conitinues to run, sometimes too well as there is no way to govern speed. You can block the air intake to kill it. You may have to give it the shirt off your back, wadded up and shoved into the air inlet.

Pat

 

[cobbkevin]

Thanks for all the help. I'll try again tonight. I might not have cranked it long enough. The only reason I opened the lines down at the pump was to see if the lines were plugged.
One of you asked if I started it on SF. I have not tried the stuff since I've cleaned the filters, I guess it might start and run for a second but I don't like using it unless it's a last resort. I'll keep fiddling and see what I can acomplish and let you know what I find out.
Thanks again!
Kevin

 

[john_bud]

Kevin,

As others have stated, I don't think you would get much gain in a vacuum bleed -- but I have NOT tried it. Might be interesting to try...

Also, I have never had to bleed after an engine was started. The air will purge from a running engine, at least in my exp.

Oh, If you have a helper. You can crack the lines open (yes, do all 3!!) and have the tractor pulled by a truck or other tractor. The "dead" tractor will need to be in high gear. Then close up the lines and pull some more. It will start and you can do that with a flat battery.

Post back with how it goes!

jb

 

[cobbkevin]

Well - no luck! I cranked and cranked but at best I only got one line with a drip up at the injectors. I'll remove the pump and take it to a shop. I think I've read that they can 'bench test' them to determine condition before they open them up. Taking it off seems like a DIY operation, but not cracking one open. That sounds much more like an expert-only operation.
Thanks for the tips! At least I don't feel like I've overlooked something obvious (like many times before)!
Kevin

 

[CATMAN]

Taking a fuel injection pump off may seem to be easy, but I warn you that it MUST be correctly TIMED to the crankshaft and camshaft when it goes back on! Normally, anyone who does remove a fuel injection pump on a diesel engine would first put the engine to TDC-1(Top Dead Center of # 1 cylinder) {#1 piston at the top and ready for the "power" stroke},then they would unbolt the pump and take it in to serviced. If one doesn't do this at the beginning of the repair, then a qualified mechanic would pull the valve cover and hand rotate the engine(going in normal engine rotation) and put the engine on TDC-1 by watching the valvetrain on the #1 cylinder. Remember that camshafts and fuel injection pumps rotate at 1/2 engine rpms, so looking at marks on the flywheel (or pinning the flwheel) doesn't necessarily mean you are on TDC-1. I recommend a knowledgeable mechanic reinstalls that pump. Too much timing(advanced) can and will melt aluminuim pistons on a direct injected diesel. This info is generic, as I am not knowledgeable about your specific tractor.

 

[john_bud]

Excellent points Catman!

Kevin, HAND rotate the engine (with a wrench or long screw driver) until the timing marks on the flywheel are visible AND the timing on the pump is set to the factory specs. This one little step will save you SO much frustration later it is amazing.

Good luck!

jb

 

[RobJ]

Actually you can do this without a lot of fuss. Mainly just note where the pums is bolted to the engine (look at paint marks, etc). In the Bosch pumps I used to do the pumps had slots on the flange for adjustment. Also our engines had a gear that connected the pump the the idler inside the front cover. This gear was to large to come out with the pump, it stayed in the case. But this gear also had slots and you could line up the oil stain marks, etc. Just make sure the engine DOES NOT get turned over and the gear stays in mesh. I'm not sure with your exact config. You should be good to go.

When I got my Kubota Manual I was surprised how untechnical the timing process is. A range of 17-19 is normal. Reading it still doesn't make a lot of sense. Maybe it will when I try it. The whole "turn the flywheel until the fuel fills up to the hole.....then when it begins to run over. One day I'll run through the procedure.

Injection Timing
1.Remove the injection pipes.
2.Set the speed control lever (1) to maximum fuel discharge position.
3.Turn the flywheel counterclockwise (facing the flywheel) until the fuel fills up to the hole of the delivery valve holder (2) for 1st cylinder.
4.Turn the flywheel further and stop turning when the fuel begins to flow over, to get the present injection timing.
5.The flywheel has mark 1TC and four lines indicating every 0.087
rad. (5*) of crank angle from 0.175 rad. (10°) to 0.436 rad. (25*)
before mark 1TC.
Calculate the angle which the projection of the window points out. If the calculation differs from specified injection timing, add or remove the shim to adjust.

Injection timing Factory spec. 0.30lo033rad {17 to 19") before T.D.C.
NOTE
The sealant is applied to both sides of the shim (Soft metal
gasket shim). The liquid gasket is not required for
assembling.
Shims are available in thickness of 0.20 mm (0.0079 in.),
0.25 mm (0.0098 in.) and 0.30 mm (0.0118 in.). Combine
these shims for adjustments.
Addition or reduction of shim (0.05 mm, 0.0020 In.) delays or
advances the injection timing by approx. 0.0087 rad. (0.5*).
If disassembling and replacing the injection pump, be sure
to use the same number of shims with the same thickness.
Refer to figure below to check the thickness of the shims.

 

[cobbkevin]

Thanks folks! You have my attention!
I softly understood that the pump had to be timed prior to its removal. I'll look through the manual and pay CLOSE attention to the procedure. I'm pretty mechanically inclined so from what I remember reading it didn't seem too intimidating. The only thing that scared me off was opening up the pump myself, it definately seems like a 'qualified mechanic' only. I think I'll completely take out the battery while the pump is removed to make sure that the engine doesn't get 'accidently' turned over while the pump's in the shop.
Thanks for the advice!!! I'll report back.
Kevin

 

[CATMAN]

One more thing, I would like you to have a "killboard" ready after you get that fuel injection pump back on and you're ready to crank it over for the first time. A killbroad is just a piece of metal ("1/8 or thicker) or a piece of wood(3/8" are so) use to shut of the air flow to the engine, if there might be a problem with the fuel pump/governor after you get it back from service. Mechanics are people, too and they can make mistakes also. There should be a hose or something removable between the intake manifold and the air cleaner that one could slide in a killboard into shutoff the airflow just in of a overspeed during initail start-up. Remember its too late if you start it and the rpms go to the moon, you have to be ready before cranking(sometimes it is a two-person job). One verifies tractor in neutral and cranks, while the other person has killboard at the edge of the intake manifold just ready to shutoff the airflow if rpms don't sound normal the instant it fires up. I don't mean to be a "Nervous Nellie" about it, but I walked into our shop about 15 years ago and our night-shift didn't follow those procedures and $100,000 later ,the customer had a replacement semi-tractor and they repaired the fire damage in the shop. I worked with the Insurance company and slowly inspected the governor work and not one but two problems that allowed the overspeed. If there had only been either one but not both problems the keyswitch would have shutoff the engine.(Killboard would have worked no matter what) To this day, anyone not using a killboard on a mechanical governored engine that has had the fuel pump or governor work done to it will be fired! On fuel pump work that we do for customers that "carry-in" their pump/governor, we tie on a BIG RED TAG that says "MUST USE KILLBOARD". When they ask "What is that?" we explain it to them. Better safe that Sorry. Good Luck

 

[RobJ]

Runaways are never fun. In my career I only had 2. Both on bosch style pumps, one was having a problem and I had the side cover off already, I was able to grab the rack and pull it back, just stuck a bit. On the other I had to use my trusty 19mm (3/4") in my back pocket to take the pressure off the fuel galley, that'll kill a bosch style in quick order. I took a #2 bath on that one.

On my Kuboto I think it has the drop in plumger stype pump and the governor is actually in the front cover on the engine, like the smaller engines I use to rebuild. The injection pump has a lever that must fit into a slot in the governor arm. Mess this up and the governor arm will push the fuel lever to max on startup. That'll ruin your morning!

 

[markct]

keep in mind that not all runaway diesels are as easy to stop as cutting off the fuel at the pump or injectors. our TD9 dozer ran away on me one time because the injector pump seal leaked diesel into the crankcase and then when it was started the diesel worked its way past the rings and it ran on that the only way to stop it was to block off the air intake

 

[RobJ]

keep in mind that not all runaway diesels are as easy to stop as cutting off the fuel at the pump or injectors. our TD9 dozer ran away on me one time because the injector pump seal leaked diesel into the crankcase and then when it was started the diesel worked its way past the rings and it ran on that the only way to stop it was to block off the air intake

Option 2...RUN FOR YOUR LIFE!

 

[schmism]

keep in mind that not all runaway diesels are as easy to stop as cutting off the fuel at the pump or injectors.

a while ago they had a story about the guys that that put out all the oil well fires... and after they got the fire out, while it was still spewing oil they said it you could never get very close because the some of the well heads would spew so much LNG that the air would get so saturated that the equipment would run on it... (sucking in fuel and air in the air inlet)

 

[randydupree]

i don't think you need to pull the pump.i think you need to fill the fuel tank,charge the battery (how old is it,it may need a new one),loosen the fuel lines,have a helper spin the engine until fuel drips out,tighten the lines and give it a shot of SF,it will run.
diesels need 500 rpms to start,if you have a weak battery/starter it will never start.i've spent my life working on all kinds of diesel engines and very few pumps have been bad in my life.
something else you can do is add an electric fuel pump between the fuel tank and the injector pump,this will help on almost any engine.
randy

 

[Luchen]

I have zetor 3320 I ne so how?ed to know if the injector pump needs bleeding and if