Author Topic: Purchased Used Lovoson 12/2 in non-working condition (Fuel trouble)  (Read 5437 times)

andreaskc

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I picked up a Lovoson 12/2 that owner thought had a clogged injector or pump. I've given the engine a decent go thru. The previous owner had been running veggie oil thru it and it stopped working after sitting one winter. Compression is good, oil pump good, changed oil, crankcase is clean.

Both fuel pump racks were locked up tight. One of the fuel pumps was seriously gunked up with a black tar mixture. The fuel line from the tank to filter was solidly blocked with the same black gooey tar. Past filter, and in pumps it looked more like regular diesel.... other than the pumps being covered in tar.

I pulled the pumps apart, cleaned them real good and now have good action in the rack. Fuel squirts out of the high pressure lines.

I have one injector now squirting out (not in engine) but no creak. The other injector had a nozzle that is nearly black and it doesn't squirt. I hooked the working injector up to the high pressure line the bad injector was on and don't get it to squirt anymore. Bad injector also didn't work on what was the working high-pressure line. Once I switched them back, the good injector works on the good high pressure line.

Both high pressure lines squirt fuel out, but wondering if I have both a bad pump and a bad injector? The pump on the bad side does seem to behave similar but it did have a spring and brass/copper washer in it that looked like it had been tweaked pretty good at some point. I had hammered the copper washer back flat before putting it together.

Here is a video of the bad line squirting fuel, not attached to injector.

http://youtu.be/O-qetCVAVx4

Maybe need a new injector and pump?

38ac

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Re: Purchased Used Lovoson 12/2 in non-working condition (Fuel trouble)
« Reply #1 on: April 13, 2018, 10:12:06 AM »
The same conditions that stick the pumps also sticks the pintles in the injectors. Seldom does one find one stuck hard and not the other.  Pumping a bit of fuel out the lines when detached tells you little other than you have the air bled out.  If you have fuel out the nozzles and no creaking noise the pintles are stuck open.  No fuel  on the #2 side could mean the other pintile is stuck closed but that only happens with a weak pump otherwise the pump will open them or burst the line.  Stuck pintles usally means a new tip is required but once in a great while a bit of heat frees them so they can be removed and cleaned. If you heat the tip or pintle enough that it changes color the slightest amount take it straight to the trash barrel.   A leaking delivery valve or bad element valve will allow a pump to push a bit of fuel when the line is unhooked as in your video but will pump nothing when attached to a good injector, a person just cannot tell for certain watching a video.

I used to think that everyone was aware of the need for cleanliness and procedures for working on fuel injection equipment but that thought has been put to rest due to experience.  Actually had a pump and injector  in the shop that the owner took apart and bead blasted "to clean them up"  Although it's not rocket science the fuel system parts are far and above the "it looks OK" test  due to very close tolerances involved. If you applied ANY kind of abrasive to the elements including steel wool you ruined them.  You cannot tell if the delivery valve is good by looking at it. A defect smaller than the eye can see will cause the seating surface for the injector tip to be serviceable.  The elements , delivery valves, injector pintles and nozzles must be up to snuff. Seen well meaning but knowledgeable (and stubborn) owners chase their tails for a long time who had same issues with engines that had set because their worn or corroded  injection parts would squirt a little fuel  when they "tested" them. But they would not operate as needed to fire and run the engine.  If I am scaring you away from trying to fix it yourself that is not my intention BUT you cannot make assumption after  assumption and figure out what is going on.

Prim and proper procedure to figure out where your issues lie requires you to pull the injectors and test them on an injector popper. This preforms 3 tests. Popoff pressure, holding pressure and spray pattern, all vitally important   Once you have the injectors set  you install them and bleed the lines if they dont creak as on the test stand you have pump issues to fix. If they creak when spinning the engine briskly but not when cranking slowly your pumps are weak but may run the engine. When everything up to snuff and bled out completely a person can feel a good bit of resistance each time the pumps try pop the injectors when turning the flywheels slowly by hand.  So you dont have access to an injector popper what do you do?  You can take all the pics you want and nobody including me can tell you if your parts are good or not except we can tell you if they are positively bad. Getting the work done at a diesel shop will cost you more than two new injectors. You have two choices, buy a injector tester on Ebay or purchase two new injectors. Once you know the injectors are good attach them to your pumps and see what hapens. if they work great, if not you then purchase elements and delivery valves for the pumps. Then your system will work as long as you have the air out and you did not introduce dirt when you worked on it.  You may get lucky if you randomly try a part or two and guess if the othersare up to snuff but the odd dont favor it. Good luck!
« Last Edit: April 13, 2018, 11:30:44 AM by 38ac »
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andreaskc

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Re: Purchased Used Lovoson 12/2 in non-working condition (Fuel trouble)
« Reply #2 on: April 13, 2018, 05:59:08 PM »
Thanks for all the comments. Looks like best action is to buy new injectors. One injector nozzle was so black from carbon/etc you couldn't see the hole and the pintle was stuck until soaking overnight. It still doesn't work (spring feels stuck), but was able to clear the hole.

Any recommendations on where to buy injectors? I'm in US/Missouri. Would be nice if they were preset/tested-ish.

32 coupe

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Re: Purchased Used Lovoson 12/2 in non-working condition (Fuel trouble)
« Reply #3 on: April 13, 2018, 07:28:18 PM »

Gary is right next door, he will be along in a moment.

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dieselspanner

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Re: Purchased Used Lovoson 12/2 in non-working condition (Fuel trouble)
« Reply #4 on: April 14, 2018, 09:17:03 AM »
Strip down the injectors, you've nothing to loose if they don't work after you've finished, the situation hasn't changed!

Google 'diesel injector' and jerk type injector pump' images before you start, to get an idea of where to start.

https://www.youtube.com/watch?v=9THAcQsQM9s

Put a large, clean piece of cardboard on the bench and cover that with a length of kitchen paper towel, stolen from her indoors, work in a clean as possible environment. Get a cold one out of the 'fridge, tune the radio to your favorite station and settle in for a couple of hours, take photo's if you don't trust your memory - I take lots!

Count the turns as you unscrew the spring and load the spring up the same amount when you rebuild.

As you strip down keep all the bits in a shallow pan of clean diesel, use clean cloth and wear nitrile gloves, or similar, as Butch said, don't use anything abrasive to clean the gunk off, just acetone, or what ever solvent you have to hand.

Use a fine copper wire (from a stripped down piece of light automotive cable) to clean the injector tip

The tip of the pintle can be reseated, reground, with Jewelers Rouge, a fivers worth off Ebay will last your entire career, about as much as you can get on a pin head mixed with a tiny drop of diesel is enough. don't get it ANYWHERE other than on the tip where you want to reseat it, afterwards clean everything out thoroughly.

Test the injector by connecting it up to the pump before fitting it in the head.

 Follow the same routine with the pump, if necessary, it's easy enough to understand how it works, from Youtube and images on the web.

https://www.youtube.com/watch?v=IjXnbFVJKRY
 
I had an Indian injector that was delivered full of what can have only been 'protective' grease, stripping it down, cleaning and reassembling it wasn't difficult, same for the pump.

Have a go!

Cheers Stef
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

BruceM

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Re: Purchased Used Lovoson 12/2 in non-working condition (Fuel trouble)
« Reply #5 on: April 14, 2018, 10:34:46 PM »
I've found that vegetable oil is a marvelous injector parts cleaner. Soaking overnight is best. It dissolves and softens up hard dark deposits quite marvelously and is very pleasant to work with.  I even use vegetable oil for pop pressure matching and pattern checking.

 I used the DIY grease gun method for making a pop tester.  Just make sure you flush it with motor oil when you're done as the seals will get destroyed if vegetable oil sits in the grease gun body.


andreaskc

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Re: Purchased Used Lovoson 12/2 in non-working condition (Fuel trouble)
« Reply #6 on: April 17, 2018, 03:15:32 AM »
Thanks for all the feedback. I’m gonna start w buying 2 new injectors and hope the clean out of the two pumps were sufficient. For grins and giggles I’ll tear down the old injectors and see if I can make a spare.

How strong is the spring inside the injector? Is this something you could depress with your hand or is it stronger than that? Asking cause on one of the injectors, the pintle and nozzle doesn’t fit flush even pressing in hard by hand. I assume the nut would tighten it down flush with enough force if necessary

dieselspanner

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Re: Purchased Used Lovoson 12/2 in non-working condition (Fuel trouble)
« Reply #7 on: April 17, 2018, 08:02:29 AM »
If the pintle isn't seating then there's probably something in the way!

Don't force it, you may well bugger the seat, strip it down and clean it out, re assemble and do a 'paraffin' test, this one......

https://www.nortonownersclub.org/noc-chat/technical1-singles-forum/419007981


Not this one.......

https://www.merriam-webster.com/dictionary/paraffin%20test

If it drips, re lap the valve.


Keep everything in under diesel whilst you're working on it, the very slightest sign of surface rust will cause damage to the fine tolerances.

Cheers Stef
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

ajaffa1

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Re: Purchased Used Lovoson 12/2 in non-working condition (Fuel trouble)
« Reply #8 on: April 17, 2018, 12:03:53 PM »
Probably not necessary to buy new injectors. Please try repairs first. You could also take them to any decent diesel injection shop and have them cleaned and overhauled for a lot less than replacements would cost. I don`t know what the correct injector pressure is for the injectors on your 12/2 but someone on this forum will know. Please have the service centre set them a few psi above that as the springs in them fade with age.

good luck and have fun getting dirty,
Bob

andreaskc

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Re: Purchased Used Lovoson 12/2 in non-working condition (Fuel trouble)
« Reply #9 on: April 17, 2018, 04:33:22 PM »
Yea, I had called a few diesel injection pump repair spots in town. Almost all of them are minimum of $100/injector which is crazy close to the cost of a new injector.

Now I have two injectors to tear apart without fear of rendering them useless!

andreaskc

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Re: Purchased Used Lovoson 12/2 in non-working condition (Fuel trouble)
« Reply #10 on: April 17, 2018, 04:41:33 PM »
If the pintle isn't seating then there's probably something in the way!

Don't force it, you may well bugger the seat, strip it down and clean it out, re assemble and do a 'paraffin' test, this one......

Just to be clear, the pintle seems to fit nicely into the body of the nozzle. When fitting the nozzle w/pintle onto the injector body, the two pins line up and the pintle flat end fits into the center hole of the injector body but there is 3-4mm of daylight between the nozzle and the injector body where the flat part of the pintle fits into the end of the spring. Pressing the nozzle down hard makes the spring go nowhere. I assume you should be able to depress the nozzle flush on the injector body?

38ac

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Re: Purchased Used Lovoson 12/2 in non-working condition (Fuel trouble)
« Reply #11 on: April 17, 2018, 05:09:06 PM »
Yea, I had called a few diesel injection pump repair spots in town. Almost all of them are minimum of $100/injector which is crazy close to the cost of a new injector.

Now I have two injectors to tear apart without fear of rendering them useless!

Yup, same as here, for just a bit more than the cost of having one injector repaired at diesel shop  you can have two new MICO Bosch injectors delivered to your house





Just to be clear, the pintle seems to fit nicely into the body of the nozzle. When fitting the nozzle w/pintle onto the injector body, the two pins line up and the pintle flat end fits into the center hole of the injector body but there is 3-4mm of daylight between the nozzle and the injector body where the flat part of the pintle fits into the end of the spring. Pressing the nozzle down hard makes the spring go nowhere. I assume you should be able to depress the nozzle flush on the injector body?

Pressure against the pintile is what makes the injector pop off instead of dribbling fuel.  Thus if you did not loosen the top screw(smart thing to not do if you dont have a tester) the tip will not go back flush under hand pressure, you have to push it back with the nut that holds the nozzle  being certain that the dowel pin stays aligned with the hole in the nozzle.

« Last Edit: April 17, 2018, 05:12:47 PM by 38ac »
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andreaskc

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Re: Purchased Used Lovoson 12/2 in non-working condition (Fuel trouble)
« Reply #12 on: April 17, 2018, 06:51:37 PM »
Is there a torque setting on the nozzle nut? Do you put the rest of the injector holder in a vise? Doesn’t seem there is anything else to grab onto other than the top which would alter the pop pressures?

38ac

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Re: Purchased Used Lovoson 12/2 in non-working condition (Fuel trouble)
« Reply #13 on: April 17, 2018, 07:28:18 PM »
yes you vise the nozzle body and i have never torqued the nut other than good'n tight.
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andreaskc

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Re: Purchased Used Lovoson 12/2 in non-working condition (Fuel trouble)
« Reply #14 on: May 14, 2018, 05:54:38 PM »
Ok, so I went ahead and ordered 2 new injectors (thanks Gary!). Just trying to test them out and not figuring this out yet.....

I've hooked one injector up to either high pressure line and not getting a squirt from the end of the injector.

I've bled the lines. I poured a little diesel into the 2-3inch tube on the injector. I've cranked the heck out of the engine... nothing, no creak, no squirt. Fuel comes out of the high pressure lines w/o the injector hooked up. I've bled the fuel out to the tip of the high-pressure line and then attaching the injector tightly. Also, I am not putting the injector into the engine head yet. I'm wanting to see/hear the injector work. Am I missing something here? Should I be looking at the fuel pump? Is there a way to measure their pressure?