injector pump check valve removal tool

[Shvegel]

Before you throw in the towel remove the barometric compensator and make sure the stem is free.  It should be stiff but not stuck.  Don't try to move it a bunch just enough to verify it is free.  Sometimes the top gets whacked and it gets stuck. 

[Shvegel]

Here is a picture of the piston and barrel.  What is referred to as an “Element” when they are together.  The top of the piston travels below the hole in the barrel.  If you look at the top of the piston you will see a ramp machined in the surface.  By turning the barrel(cylinder) you move the point at which the ramp on the piston meets the hole in the barrel.  The piston travel is always the same but by rotating the barrels you can alter the fuel supply to the injectors.  The farther to the left on the ramp the more fuel you get.

[ja17]

Sorry for jumping in late, but what is the history of the problem? I did not see it in previous posts.

[County Guy]

OK.  I didn't want to just leave this thread with out summarizing where I am at this point. 

I measured the Fuel Injector Pump location at 20 ATDC and though the toothpicks were 10mm shorter than expected, I have concluded that the FIP was installed correctly.

I have gone back to basics and I checked the compression and it is pretty good.

I checked and adjusted a couple of valves that were off.

I pulled the plugs and looked them over.  They seem fine.  I checked the timing of the distributor making certain that the 1st. cyl. was on the compression stroke.  That seems correct.  The spark plug wires are almost new but I looked them over, particularly where they connect to the plugs.  Everything seems ok.

I'm going to look at the ignition timing and dwell tomorrow but I don't expect to find a problem there.

If I am still having a problem with poor performance, I will be flummoxed.

Thanks for all your tips and suggestions.

Lockie

[Benz Dr.]

Go back and look at your ignition wires again. Even new sets can have wrong parts in them. I've found most new sets have carbon core coil wires which would need to be changed to steel core. You can save and use the boots with terminals from the old ends if you have to change any wires.

[County Guy]

Thanks for that suggestion.  I did pull the wires while the engine was running and didn't see any noticeable effect on a couple of cyl.  You are suggesting steel core?

On another track.  I bought "Progressive Regulator Linkage" bushings from Mercedes.  One is very worn.  (180 072 03 50) but the interior diameter seems too small to fit over the post.  Have you ever encountered this?  It looks like I will have to drill it out to get it to fit over the post.

[mrfatboy]

Regarding the bushings I ran into that problem also.  That is how the come.  You will need to use a drill or lathe to get the proper fit.  I still have not done mine yet😜  Every car will be slightly different due to wear.


The spark plug wires should be copper core.

[County Guy]

Thanks.  I'm going to work on the bushings today.  It looks like the outside diameter is correct.

OK.  Copper core wires they will be.

By the way, shvegel, I'm sorry i neglected to respond to your suggestion re;barometric pressure barrel. I did press on what seemed to me to be the top of the barrel after the compensator was removed.  I used a shishkabob stick to make sure the barrel moved when pressed and it did move.  I concluded that it was functioning properly.

[Tyler S]

I did pull the wires while the engine was running and didn't see any noticeable effect on a couple of cyl.

You should definately see a noticeable rpm drop and engine stumble when each plug wire is removed while running. If not then zero in on these cylinders. A non contributing cylinder (or 2) can be caused by ignition, fuel injection, or compression issues.

[Benz Dr.]

Most neew wire sets are probably stainless steel or something similar but the wire set doesn't have to be copper. I'm talking about the coil wire.  On most of the sets I've seen it's actually a carbon core wire and it will cut voltage back a lot. Get a piece of new plug wire and save the old ends from the carbon wire so you can use them again. If it is carbon core you won't believe the difference when you change to metal.

I bet half the cars out there have carbon coil wires.

[ja17]

Carbon wires add 5k ohm resistance to each plug wire, add another 5k ohm resistance from a carbon coil wire, then add another 5k ohm resistance for resistor spark plugs.  All of the sudden you are 15k over specs!

Make sure you are getting full throttle also!

[Benz Dr.]

Carbon wires add 5k ohm resistance to each plug wire, add another 5k ohm resistance from a carbon coil wire, then add another 5k ohm resistance for resistor spark plugs.  All of the sudden you are 15k over specs!

Make sure you are getting full throttle also!

And when you add 5K for the rotor you'd be lucky to get it to run.

Frankly, the right way to do this job is to remove the pump and look. Sometimes all of the info on our site leads the unsuspecting down rabbit holes.