220D Surging Idle (Misfire?) After Governor and Injector Replacement - PeachParts Mercedes-Benz Forum

73220downer · #1 02-19-2019, 08:38 PM

A couple weeks ago I ordered new injectors (remanufactured Bosch ones, from Pelican) and decided to take the IP off to change a of couple oil seals. After I had gotten it apart I decided to replace the governor diaphragm while I had the pump off and then replaced the o-rings on the poppet cam. After I got everything back together and bled the air from the system the engine started but actually runs worse than before. It has a violent surge at idle, shaking from side to side along with some nailing. The problem disappears with my foot on the gas pedal. It was present before but only at a certain rpm range (about the mid-point of the idle adjust knob range) and not as bad.

What might cause this? Do I need to adjust the linkages? Did I fudge up the timing?

73220downer · #2 02-19-2019, 10:12 PM

Dirt in the pump maybe?

Diesel911 · #3 02-19-2019, 10:44 PM

Kind of a good idea to do one thing at a time.

Note dirt in an injector can also cause issues. Also we have no way of knowing if the shims and springs go back were they were supposed to be.

From my notes. There is supposed to be how to test the Pneumatic Governor in this threads.
Shows old Pneumatic Governor and shows gravity feed drip timing also has pneumatic governor tests
http://www.benzworld.org/forums/vintage-mercedes-benz/1494188-75-240d-injection-pump-oil-consumption.html
Governor Diaphragm Test
74 240d Grey smoke questions

Not sure what is in this thread: Governor Diaphragm
What are the symptoms of a bad IP Governor Diaphragm - PeachParts Mercedes-Benz Forum

See if removing the Breather Cap changes anything.

The surging could be caused by non-governor issues like air getting into the fuel supply, the fuel supply/lift pump, and the fuel pressure relief overflow valve.

How about that tubing going to the venture in the intake manifold and the venture itself? How about the butterfly valve?

No one has used it but there is actually a tool for setting up the proper shims on the diaphragm. Maybe yours is the one case where you need to tool get the proper shim thicknesses.

It has been a long time since I have seen one but a new governor diaphragm is so flexible it is kind of creepy looking. If it was a diaphragm that sat on the shelf for a long time it might have become some what stiff.

Diesel911 · #4 02-19-2019, 10:57 PM

.pdf

73220downer · #5 02-23-2019, 12:10 PM

Another hint: loosening the flare nut on cylinder one's injector not only doesn't make the car run worse, but very little fuel comes out as well

Also the vacuum system does hold vacuum, and there are no air bubbles coming out of the return line

73220downer · #6 02-23-2019, 10:45 PM

A poorly adjusted governor wouldn't cause poor fuel delivery to only one cylinder would it?
I should mention it seemed to "spit" fuel when I tried to time it as well

Diesel911 · #7 02-24-2019, 08:28 PM

Quote:

Originally Posted by 73220downer

A poorly adjusted governor wouldn't cause poor fuel delivery to only one cylinder would it?
I should mention it seemed to "spit" fuel when I tried to time it as well

You could remover the Plate on the side of the Fuel Injection Pump (it is behind the top of the Fuel Supply/Lift Pump).
When you look inside you will see the Tappet Return Springs, the Element Plungers and the Collars with teeth on them (the teeth interface with the Rack).

Look for broken Tappet Springs.

Working the manual shutoff should allow you to watch the Collars turn and the Tubes the Collars are attached to should also turn with them. If the tube is not turning look for a cracked collar with teeth. They usually crack near where you will see the screws used to camp it around the tube. Or if you are looking at a sliding rod with blocks with screws on it (don't loosen any) check and see if any of the blocks are loose and will slide on the rod.

Next you will do what is needed to rotate the Fuel Injection Pump slowly and watch the plungers which are in the center of the tappet springs. What you want to see is the Plunger go all the way up and all the way back down.

You might find that the #1 is stuck in the all the way up position.

73220downer · #8 03-01-2019, 08:49 PM

Well... I took the DV holder off again and the collar did indeed turn. I took the barrel out and lo and behold: it's not seated right. It won't seat right. It makes sense now: I torqued the damn thing down with the notch out of alignment. The barrel came up when I removed the DV with a magnet and thought nothing of it until I read a couple threads this evening.
Should I just get a new (or new to me at least) pump at this point?

Diesel911 · #9 03-02-2019, 01:57 AM

Quote:

Originally Posted by 73220downer

Well... I took the DV holder off again and the collar did indeed turn. I took the barrel out and lo and behold: it's not seated right. It won't seat right. It makes sense now: I torqued the damn thing down with the notch out of alignment. The barrel came up when I removed the DV with a magnet and thought nothing of it until I read a couple threads this evening.
Should I just get a new (or new to me at least) pump at this point?

There is a pin down in side of the bore that goes into that slot on the Barrel. If the Pin is not bent or the housing is not cracked and you can get that pin back into the slot and the barrel all the way down there is a good chance it will be OK.

Another thing that can happen is that the alignment pin can get pushed to the side and you won't see it in the bore or only see a small portion of it. If you remove.

You are going to say it is too late but one of the ways to avoid tightening it down when the barrel is not lined up is to measure the height of the delivery valve holder before you remove it. Then before your torque the delivery valve holders down you run them down till they are just slightly snug. Then you look at the heights to see if they are all the same. And they you can also use your measurement.

When I was a beginner at the fuel Injection shop the same thing happened to me several times. Apparently if you torque the delivery valve holders down to the proper inch pounds in my case it did no damage to the inside of the Fuel Injection Pump Housing.

Any way it is worth a try to try reinstalling it properly.

In the first pic you see the slot on the side of the barrel. Your's could look different as this is not a 220D element/barrel.

The next pic is showing the alignment pin in the bore. Still not at 220D pump but you get the idea.

If the alignment pin has been push to the side you can remover the cover and you will see the other ends of the pins with punch marks staked them in place. The pushed out pin needs to be care fully punched back in to the depth of the other. Don't stake the pin in until the barrel is seated correctly and re-installed all of the parts and torqued the delivery valve holder (comparing the height to the other delivery valve holder that you know were done correctly before tightening).

After it is running you need to check that drip tube. If fuel starts and keeps dripping out of that bent tube on the bottom of the pump it means the Barrel is not seating well and then you may indeed need another Fuel Injection Pump.