Fuel Injection Pump freeing up after sitting for many years

[Pinder]

I have been working on the fuel injection pump and have managed to free it up so the rack now moves freely. Howvever on one piston at the top of the stroke the rack binds. its almost as if the piston is coming too far up. this may free up but was wondering if there is any kind of tappet adjustment ? also what are the siz large slotted screws on the side of the pump for? do they hold the pistons in place?

Regards

Pinder

[Shvegel]

Piston stroke is not adjustable you still have some gunk in there.  I ran Lacquer thinner through my pump after freeing it up.  As an alternative you can search how to remove the delivery valve under the outlet fitting and clean it from the to of the cylinder.  The slotted screws on the side are for access to compress the springs so you can remove the camshaft.

[Pinder]

Ive got all the pistons moving up and down. 5 work perfect and one is still a little sticky. I took the fitting off the top and removed the valves using a threaded fitting. the rack is also moving although not totally easy to move but it does move. Im thinking when its in the car with fuel running thru it and oil that evently it should free up some more.

Any thought on this?  I know the right thing to do is send it off for a rebuild but thats also the most costly option and hard schedule right now as I'm already hemorrhaging cash on the parts for the engine rebuild.

[450sl]

This product works ,use it undiluted:

http://www.liqui-moly.de/liquimoly/produktdb.nsf/id/en_5110.html?OpenDocument&land=GB&voilalang=e&voiladb=web.nsf

[scoot]

When I brought my injection pump back to life it was part of cleaning the entire fuel system back to front.  The pump itself was cleaned by running an auxiliary fuel pump that was connected directly to the fuel inlet.  What I pumped through the injection pump was a mixture of the nastiest carb cleaner you can buy (80%) with a little ATF mixed in (20%).  I believe that Teulene is also used, but can't be purchased in California so the carb cleaner was the strongest stuff I could get.   First I pumped it through the pump and captured the output on the return from the pump - no cranking of the engine at this point.  Then I repeated except had made some little injection lines that feed into plastic bags and ran the aux fuel pump again while cranking the engine.  I did this until the fluid coming out of the 6 injector lines was clean (or looked like what was going into the pump) and then until the approximate volume coming out of each of the lines matched. 

You can search for threads started by me regarding my M189 engine for more information, but here's a few pics of the cleaning of the injection pump.  The short fuel lines from the pump were made by salvaging injection lines from a diesel at the junkyard, cutting and bending them.

You can also watch the videos on Kent Bergma's MercedesSource youtube channel on the resurrection of the 300SE 6.9 (might be called resurrection of the beast) -- different engine, same process.

[Pinder]

Thanks for the info. I do have a fuel pump I can use to hook up into the system. right now the engine is also out and I have the injection pump on m bench, I was thinking of hooking up a pump to it, and use my existing lines and then do as you are doing put some cleaner (maybe lacquer thiner or something like that) and simulate it in operation with a drill running at high speed to camshaft. I should be able to balnce it so all the cylinders are producing the same amount of fuel.  I am trying to make sure I cam confident it will work before I bolt it back to engine and engine back into car. Don't want to be doing this twice.

[scoot]

Thanks for the info. I do have a fuel pump I can use to hook up into the system.

Lesson learned 1:  You may well trash the fuel pump you use for testing.  I bought a fairly cheap one at autozone and it could only tolerate the cleaners for a little while before dropping pressure to uselessness.  I bought a second one that held up much better - a Carter P4070, something like $65 on Amazon.  I would flush the fuel pump with diesel or alcohol after use to keep it from crapping out.  You need the slightly higher pressure to get the injection pump to work right and feed the pistons.

right now the engine is also out and I have the injection pump on m bench, I was thinking of hooking up a pump to it, and use my existing lines and then do as you are doing put some cleaner (maybe lacquer thiner or something like that) and simulate it in operation with a drill running at high speed to camshaft.

Laquer thinner is good for some times of contamination, not others.  For cleaning I would recommend Tuluene if you can get it - 80% and 20% ATF.  The pump is going to need the ATF or something to provide some lubrication.  Also, you have a 1970 car which means that it uses the oil supply from the engine, rather than the separate isolated oil supply on the earlier injection pumps.  I assume it is critical for you to have oil in the injection pump and I'm not sure how you do that when it is on a bench, but I'm sure it's been done and someone else will know the answer.  I'm not sure how you are going to connect the drill to the drive on the injection pump, but it sounds like a nice idea.  I _think_ it is important for the injection pump to be turned in the correct direction, which I don't know what is, and I'm not 100% certain about this anywayl

I should be able to balnce it so all the cylinders are producing the same amount of fuel.  I am trying to make sure I cam confident it will work before I bolt it back to engine and engine back into car. Don't want to be doing this twice.

Well you can't really balance it.  If you get it clean and the rack is moving properly and RETURNING to the right spot when you move it and if all the pistons are free, it should be sending out the same amount of fuel to each injector line.  This will be much easier if you make stubby lines like in my pictures, and diesel injection pumps are plentiful at the junkyards so getting a set of lines and trashing them isn't an issue.  Same size fitting.   If you try to use your original injector lines you end up with fastly different lengths that the different lines have to fill with fluid, fuel, cleaner etc and it will be difficult to tell if you are getting equal amounts

Here's a video (from an M189 engine) that shows nicely how the rack should move and return when a little pressure is applied to a screw screwed into the rack.  If you aren't getting this type of movement and return, you aren't done cleaning.
https://www.youtube.com/watch?v=QYF04sW27us

[Pinder]

the video is helpful and so are the other suggestions.  I've used an rachet with a 19mm nut on it to simulate turing. I've been turning it clock wise . for the holes I am thinking of using clear plastic type hose with some hose clamps. I can then put them into jars.  but the rachet has a bit of a impact motion to it and is limited in speed . I plan on using the 19mm socket stepped down to fit a 1/4 inch drive then i can get it into a variable speed drill.

[scoot]

the video is helpful and so are the other suggestions.  I've used an rachet with a 19mm nut on it to simulate turing. I've been turning it clock wise . for the holes I am thinking of using clear plastic type hose with some hose clamps. I can then put them into jars.  but the rachet has a bit of a impact motion to it and is limited in speed . I plan on using the 19mm socket stepped down to fit a 1/4 inch drive then i can get it into a variable speed drill.

I'm not sure what holes you mean but if you are using clear plastic tubing with various mentioned chemicals it might dissolve rather quickly...   Ask me how I know!  I was using clear tubing to see the fluid coming in and out of the pump and after a bit the tubing turned into something like string cheese.

19mm nut and a variable speed drill sounds good.  You don't need to go real fast for this btw...

[Pinder]

Thats a good point. I was thinking about that. I will likely use black hoses used for gas lines. they should hold up to the solvent. Clear like you said will melt. I once left some in a plastic cup and it melted. i have made some more progress on the rack and one stuck tappet using sea foam and carb cleaner. been working it last few hours back and forth. tappet was sticking on way down sort of half way. I have it now going down and up. still want to get the rack free in all positions. if the suspect piston is on the top stroke. (spring compressed) it gets stiff but i can move it. It is better but not perfect. ill work it with diffeent things and hope it frees up like the others. thanks for your help.

[scoot]

. i have made some more progress on the rack and one stuck tappet using sea foam and carb cleaner. been working it last few hours back and forth. tappet was sticking on way down sort of half way.

My understanding is that the rack won't work right unless you get all the pistons moving right, and then the rack will settle into position, and re-center itself if you push or pull the screw you have (I assume) screwed into the rack.  I don't think (but not sure) that moving the rack around does any good until the pistons are all working well. 

Clear tubing can be really useful for some of the cleaning process - it lets you see how clean things are in a much better way than just having it collect in a container.  But it also will have a very short life in that usage. 

[Pinder]

Scoot

my Pump has no screw you can screw into, the later pumps dont.  but I can move the rack about by moving any of the piston colars (things with the screw around them . look like a pipe clamp). its in better shape than yesterday but Ill keep going at it every day . hopefuly it will free up totally.

[scoot]

my Pump has no screw you can screw into, the later pumps dont. 

How inconvenient!  I assumed there was one under the black plastic cap but I just removed one of those caps and no threaded hole! 

[Pinder]

still binding on the one piston in one position. Ive take the nose of the pump and am attempting to pull the cam so i can take the pistons tappets and spring out and soak it . Those screws were on really tight but I managed to gorrilla them off. the problem i have now is I think i need a special socket to remove the governor. I got all the springs out but where can i get the socket for the nut that looks like its a two tower castle nut?

[tel76]

Pinder,
I think you are getting out of your depth, have you any idea what the equipment looks like to set up one of these pumps correctly.
Many years ago I attended a course at the Bosch factory on how to set up these pumps, you cannot do it in your garden shed.
If you look in the items for sale you will see a member is selling an overhauled unit, take a deep breath and go that route.
This is one item that you cannot afford to play around with, it will cost you more in the long run.

[Pinder]

I think so too. Its a last resort option before i go down the road of sending it off for a rebuild.  For now I went and got some Chem Dip and have it soaking in there. Ill leave it for 24 hours and hope it frees the last sticky piston.

i also think I have found the tool to open the nut think its called a KDEP 2998.

[twistedtree]

If the FIP is as bound up as you describe, then even if you get it freed up the internal seals are likely shot.  I'd stop wasting your time and send it to Hans at H&R.  Also send the injectors and cold start valve and you will get back a fully functional injection system.

[Pinder]

That may well be what I will have to do. If it does not free up and I feel confident it is working how i think it should. Its trying to justify to "Her in doors" of spending another 2K on a injection pump. Im already feeling the pinch with the current parts list adding up fast, Pistons alone were over 1K. and I'm having the head worked on so that wil not be cheap. how much is a rebuild from H$R?

[twistedtree]

Give them a call.  As I recall it was $1200, but that was a few years ago.

[Jonny B]

As another point of reference, I had my 280 SL pump redone at Pacific Fuel Injection - it was $1600, this was in February of this year (2015)

[Pinder]

Thats good to know the rough price so I can prepare for it mentally.

[Pinder]

I have made further progress in freeing up piston number #6.  I soaked it in carb cleaner up for 24 hours ( made minor difference) cam is now totally clean of varnish etc.) then out of sheer frustration I pulled the cylinder out for #6 and put a tube in the cylinder and wiggled the heck out of it. plus more sea foam. after that the binding occurs in 5 degrees of rotation of the cam at top of strock. It used to be 15 degrees. So I will repeat process again and hope to report that its all free. In all other rotations the pump is running free.

[Pinder]

Its totally free now. Took some more chemdip and rotations and fooling around.Rack returns to center (actually slightly off center).

What worked:

Repated removal and cleaning of sticky bore, Spray with WD40 and Sea Foam. trans fluid. Chem dip soak. Moving rack back and forth while turing with air rachet on end of drive shaft. Hours of this for two days freed it up.