Injection pump was off when I got the car, put it back on to test and see if it is any good - and of course find out what parts I need yet to get for the car..

I have fuel in the injection pump... just won't prime to the injector lines. What am I doing wrong? Any advice is appreciated.

https://www.youtube.com/watch?v=yh5r01d52mE

The instructions from this old post should help.
W123 1983 240D not starting HELP

__________________
78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

I've tried, does it make a difference as to whether I've cracked all 4 lines, or just 1? I'll give it another try one line at a time. I've never had one this stubborn.

You can do one line at a time, but start with the rearmost one first.
It can take a lot of cranking to re-prime the high pressure fuel circuit on an air bound injection pump.

If the IP has been disconnected for a long time you may have blockage from dried fuel residue, polymerized alternative fuels, interior rusting of parts, etc.

__________________
78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

Are you sure you are getting Fuel for the Fuel Supply System. That means fuel from the Tank and through the Fuel Injection Pump and out of that Fuel Pressure Relief/Overflow Valve and out and back to the Fuel Tank. That is what feeds fuel to the Fuel Injection Pump. You do that by pumping the Hand primer.

If the Fuel Injection Pump has sat for a long time not used the fuel inside of it can solidify. When you crank the Engine the plungers go up and they stay stuck in the upwards position. When that happens you can't get any Fuel out of it.

If your fuel injection pump has a cover similar to the black cover in the attached picture you can remove the cover and look inside (with a mirror if needed). As you crank the Engine what you want to see is the springs inside going up/compressing and then coming back down/decompression. If the springs are staying up compressed you are having that sticking problem I am speaking of. The cover is the black part in the picture.

If you don't have that type of Fuel Injection Pump ask me for more info and I will tell you another way to check.

Attached Thumbnails

 

__________________
84 300D, 82 Volvo 244Gl Diesel

Not if the pump only saw diesel fuel.


However, I do concur with the idea of opening up the side plate to watch that the internals are moving up and down, and the fuel rack goes back and forth with movement of the throttle linkage.


More likely than not, the injection pump is air-bound and you need to get it properly primed. Next most likely would be that the governor is sticky (it is lubricated with engine oil) and holding the fuel rack in the off position.

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

That is not true. I have seen it happen to rebuilt Fuel Injection Pumps that sat on the shelf for a year. And it is even more likely with some fuel injection pump that sat off the engine in someone's garage.

On Fuel Injection Pumps that have been on the vehicle the other issues is water in the diesel fuel that causes rust inside of the Elements. That will also of course sick the plunger upwards.

Another issue can be the hole in the side of the barrel that allows fuel to get inside of the element can be plugged.

In the pic is from an MW Fuel Injection Pump showing the fuel feed hole.

Attached Thumbnails

 

__________________
84 300D, 82 Volvo 244Gl Diesel

Here is a pic of an Element, plunger and barrel similar to an M type fuel injection pump showing the fuel feed hole.

Attached Thumbnails

 

__________________
84 300D, 82 Volvo 244Gl Diesel

My pump looks nothing like yours, no black plate on mine. its an MW unit. It was off the car but has only ever been ran on diesel. I posted a video in the OP to have a better look if you wish.

The reason the pump was off was because the engine was replaced by the PO who never finished the project.

Haven't had the chance to play with the priming again but I'll try the one line at a time method maybe that'll give more pressure to the pump...

What's the process for cleaning the elements? Or should I just get new ones (assuming I take the elements out and am able to prime fuel into the chambers?)

Rebuilt pump - are you sure they used diesel fuel to calibrate it? Perhaps it was drained of fuel, left open, and rusted?


It is very common for old diesel engines that have sat for years and years to fire up just fine, once a fresh battery is installed, with no need to do any service to the fuel system prior to start up, as long as they only see #2 diesel as a fuel. Run veggie oil of any kind, all bets are off.


Given that this pump was off the engine, it may also have drained the fuel and then humidity in the air would cause corrosion.


Back to the original post, it might be best to find a good used pump or get a rebuilt pump.

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Yes as my Bosses business struggled we started using Diesel Fuel Instead of Calibration Oil in the Test Stands.

And after several months in the Machine Diesel Fuel smells really rank.


I have taken a part quite a few Fuel Injection Pumps that had droplets of Water inside of them.

People were not running veggie or biodiesel when I worked in the Fuel Injection Shop.

__________________
84 300D, 82 Volvo 244Gl Diesel

Does Fort Meyers FL sound like a humid place?

__________________
84 300D, 82 Volvo 244Gl Diesel

I looked up what a 1979 240D Fuel Injection Pump looks like and it shows an MW Fuel Injection Pump.
If that is the case he has no cover on the side to look into.


In order to tell if the Plungers are sticking on an MW Fuel Injection Pump he should not touch the 13mm Nuts on each side of the Delivery Valve holder but remove only one of the Delivery Valve holders and making sure not to lose any parts.
Remove the center delivery valve and look down inside and he should see the top of the plunger. As he cranks the engine if everything is OK he should see the plunger going up and down.

If not the way to free up the plunger is to get a 3 inch piece of 3/16 or 1/8 inch brass rod (brazing rod works) and round one end of it. Spray in some WD-40.

You stick that down on top of the plunger and use something light weight to tap on it gently. The problem is that you don't know what position the camshaft inside of the Fuel Injection pump is at. IF is at the top no amount of tapping is going to free the plunger.

Rotate the Pump a bit and tap again and rotate again and tap again till the plunger moves down.


I don't like giving people this sort of instructions as I don't know how heavy handed they are going to be.

__________________
84 300D, 82 Volvo 244Gl Diesel

Well, you did say tap tap gently, not "smack it with a BFH", so I think your covered...

__________________
95 E300D gave away
77 300D, 227k, station car
83 300CD 370k, body gone away to the rust gods, engine is in a Yota pickup, going strong
89 190E 2.6- 335k, no more
79 VW FI Bus- 154k summer driver
59 VW Beetle ragtop- 175k
12 VW Jetta- 250k
74 MG Midget-78k

Alright, I tried re-priming the pump and I still can't get fuel to come through. I'll pull the delivery valve when I get a chance to look at the plungers. I have my eyes on a replacement injection pump as a last resort - but if I can get this one going, I'll be happy as a clam. Can't put all the other pieces back on the car until that engine is running.

I'm concerned that it isn't rotating at all for some reason, is there a way to see if the camshaft is actually turning when I crank the engine?

I may or may not be missing some kind of union between the IP and the block.. Any chance someone has maybe an exploded diagram of the union between the IP and the engine?