Stuck injection pump - Page 2 - PeachParts Mercedes-Benz Forum

nikkondy · #16 02-20-2014, 11:35 PM

Quote:

Originally Posted by barry12345

I just like to see any car that has used wvo and sat around for a period of time subject to a good system soak and cleaning. When pumping the injection pump full of a solvent you get any residual stuff in the lift pump soaked as well. By products of wvo seem to change consistancy with time. Becoming a glue like substance or extremely sticky.

I do not think the suspect stuck element piston is that big of a deal. I did suggest soaking the relief valve as well when off as it may be held open by the stuff . The lift pump is covered my way at the same time.. Easy for a valve to be stuck in there as well. Or not sealing as it should with waste buildup. Removing the secondary filter dumping it and filing it with the laquer thinner gets the thinner into the injection pump quicker as well.

I right or wrong approach things so I will not have a road stoppage issue or reduce the chances of one as much as possible. I learnt long ago that any stoppage on the road you cannot quickly rectify will cost you money usually. Overall you will normally lose a days time with the event. In fact they can be a real inconvienience if well away from home.

I think I am going to remove as much of the fuel line, connections, and fittings as possible, and clean them out with solvent just as a precaution. Avoid getting the gunk in places it should not be. I also believe that the system needs a good cleaning after sitting for so long. I don't want my injectors to gum up. As a matter of fact I might get them pressure tested just to be sure and have piece of mind. In my state the diesel is bad as is so a cleaning shouldn't hurt.

If filling the primary filter with solvent I got to remember to block of the return so I don't get solvent in the tank.

Diesel911 · #17 02-21-2014, 02:02 AM

Quote:

Originally Posted by GregMN

If it is a stuck plunger: would it work to put hydraulic pressure against the top of the plunger to push it down onto the cam and then hold it there while the cam is rotated enough to free it ? If so, what would the best fluid be ? ATF, MMO, Seafoam, diesel, B100

The advantage of this method (if it is viable and works) would be that you do not have to open up the pump and risk having things go horribly wrong.

The Delivery Valve only allows Fuel to go out of the Fuel Injection Pump. That means you need to at lest remove the Center Valve from it. And, if you intend to change the Copper Crush Washer I believe you need to remove the whole Delivery Valve anyway.

The problem is that you do not know what position the Camshaft Below it is in.

If the Camshaft is positioned so that the Lobe is at the Top and you apply Hydraulic pressure you may damage something.

If you tap it as I suggested you have little chance of damaging anything.

Unless the Plunger is actually rusted to the Barrel it should not take much force to move it.

I never explains what happens.
Either the stuff in the Fuel Injection pump dried up with the Plunger all the way to the top or there was gunk dried up inside of the Barrel and the Plunger was pushed up through the gunk and wedged in.
The Plunger only needs to be wedged in enough to keep the Plunger Return Spring from bringing it back down.

If the Plunger was rusted in the up wards position or the Plunger was pushed up over rust it is going to be stuck a lot harder and the Plunger and Barrel will have some damage.
The Damage may or may not effect performance but would decrease longevity and may make the Fuel Delivery off on that Element. But, you would not now until you run the Engine.

Diesel911 · #18 02-21-2014, 02:20 AM

Quote:

Originally Posted by nikkondy

Thanks for the great advice, but I have a few things I want to clarify.
I have attached a picture from the Mercedes manual. When you say to remove the delivery valve holder, spring, and 2 piece valve are you referring to the parts that are in the image. If so how do you remove (6) or pressure valve carrier as they call it. Is it a press fit?

From what I can remember you can rotate the engine by the powersteering pulley instead of the crank if the belt is tight enough. Correct?

Someone else mentioned that it is best to soak it in paint thinner, so I might try to do this to free things up a bit before taping it to make things easier.

Also, is the method you described above possible with the injection pump off the vehicle? Would it be easier to take it off or do it with it still on the vehicle?

Since you are supposed to change the Copper Crush Washer you would remove everthing from the Fuel Injection Pump that is in the picture.

Also note that the Central Valve in the 2 piece Delivery Valve Assembly only goes into one side and it is only going to seal properly on one side. There is a ring around the outside Diameter of the Delivery Valve Assembly that you need to note if that ring is on the top or the Bottom so you can assemble it the way it came out.
That outer Delivery Valve Body is not press fitted into the Fuel Injection Pump Housing. It is likely stuck on the Crush Washer.
Stick the Brass Rod inside and pry gently from side to side to see if yu can loosen it.

You can do what I said with the Fuel Injection Pump on the Engine but of course rotating the Fuel Injection Pump means turning the whole Engine. Also it will be harder to keep crud from getting inside.

For someone else reading this the OP has an MW Fuel Injection Pump; do not do this on an M Type Fuel Injection Pump because the parts are different.

Also remember that the Delivery Valve Holder/Pipe is torqued with Inch Pounds and not Foot Pounds.

Diesel911 · #19 02-21-2014, 02:30 AM

Quote:

Originally Posted by GregMN

If it is a stuck plunger: would it work to put hydraulic pressure against the top of the plunger to push it down onto the cam and then hold it there while the cam is rotated enough to free it ? If so, what would the best fluid be ? ATF, MMO, Seafoam, diesel, B100

The advantage of this method (if it is viable and works) would be that you do not have to open up the pump and risk having things go horribly wrong.

The OP has an MW Fuel Injection Pump and he would not be removing any more than is needed if He did a Drip Timing on #1 and changed the Crush Washer because on the MW Fuel Injection Pump the Crush Washer is at the Bottom of all of those parts.

The M type Fuel Injection pump has a different parts and a different arrangement of the Parts. Also if you raotate an M Fuel Injection Pump without the Delivery Valve stuff assembled your risk pusing out the Barrel of the Element past the notch that lines it up properly.
And infact pulling up on the outer Body of the Delivery Valve can pull up the Element Barrel.
The above has happend to a few Members during the changine of the Delivery Valve Holder O-rings and Crush Washers and it did cause trouble.

Diesel911 · #20 02-21-2014, 02:38 AM

Quote:

Originally Posted by nikkondy

The picture on the right is what I don't want to remove. Its what you referred to as the two nuts on the side of the pipe connection. Good thing I read this because I as thinking about removing it to see if it was gummed up. But, I saw the nuts were painted with a paint pen and had my doubts.

Don't remove the Nuts at all. When they test the Fuel Injection Pump on the Test stand they rotate the whole Element Barrel to adjust each individual Element for the proper Fuel output.

A tiny amount of movement changes the amount of Fuel a lot.

Under the Flanges of the Element Barrel you see there is Shims. Those Shims adjust the begin of Injection for each individual Element.
The Begin of Injection for the #1 Element would have been adjusted to the Timing Mark on the Front Bearing Cap of the Fuel Injection pump.

The rest of the Begin of Injection timing for the other Elements would have been done with a Degree Wheel attached to the drive end of the Fuel Injection Pump.

benzdude42 · #21 02-21-2014, 08:09 AM

You could also run 100% diesel 911 through. It's main job is to undue gelled diesel from the cold, but it's a good solvent also. ATF will free up the pump also.

Diesel911 · #22 02-21-2014, 12:13 PM

If his Element Plunger is stuck upwards I think it there is only a small chance some chemical is going to free it up.

If the Fuel Feed Hole is plugged a Chemical might work to clear that hole.

If all of the Delivery Valve parts are removed Chemical could be poured into the Element from above.
The Fuel Injection Pump Throttle Arm woul need to be in the Shutoff position; or even better if the Element Plunger was at the bottom of the Stroke.

If the above was done and either the Fuel Inlet Banjo Bolt was removed or the Fuel Pressure Relief/Overflow Vavle is removed compress Air can be pushed down into the Element and that might bolw out a Plug in the Element Hole.

I don't know if it is possible to use a the bent end of a soft Steel Wire and go down into the element with the Element Plunger at the Bottom of the Stroke and push out any obstruction in the Fuel Feed Hole.

I think the Fuel Feed Hole faces towards the Drivers side of the Car (US models).

barry12345 · #23 02-21-2014, 12:48 PM

Quote:

Originally Posted by Diesel911

If his Element Plunger is stuck upwards I think it there is only a small chance some chemical is going to free it up.

If the Fuel Feed Hole is plugged a Chemical might work to clear that hole.

If all of the Delivery Valve parts are removed Chemical could be poured into the Element from above.
The Fuel Injection Pump Throttle Arm woul need to be in the Shutoff position; or even better if the Element Plunger was at the bottom of the Stroke.

If the above was done and either the Fuel Inlet Banjo Bolt was removed or the Fuel Pressure Relief/Overflow Vavle is removed compress Air can be pushed down into the Element and that might bolw out a Plug in the Element Hole.

I don't know if it is possible to use a the bent end of a soft Steel Wire and go down into the element with the Element Plunger at the Bottom of the Stroke and push out any obstruction in the Fuel Feed Hole.

I think the Fuel Feed Hole faces towards the Drivers side of the Car (US models).

Diesel 911 knows his stuff with these pumps. Usually a stuck element will not be too difficult to free up. Anything I have read on your site so far is a reasonable approach.

Incidentally if you even had used even just diesel oil once in awhile an element piston might hang up from long term storage.

This is besides your issue but when getting a used pump to me it is preferable to source it off an engine where it is still full of fuel. There is far less chance of any corrosion in the bores. Or when storing one of these old pumps for future use in a bucket of furnace oil after really cleaning the pump down with all the ports sealed first is the best hope it will be functional when needed. Remove the port covers after the extensive and meticulous cleaning before submerging it in really clean liquid for storage and close the container.