maintainance and techincal question about mercedes 220se W111 - PeachParts Mercedes-Benz Forum

ornas · #1 05-05-2013, 04:02 PM

hi, I've got 1964 W111 220se coupe and I've got couple questions.
My car has fuel injection system that I have never faced before. Fuel pump has red cap with "oil" written on it. Do I have to add oil to fuel pump? if so, how much and what kind of oil?

Tried to pass smog test, but my CO2 is over 10, it has new spark plugs, timing is checked, valve clearances are also good, could someone tell me what else could couse such bad CO parameter? is it time to replace injectors?

thank you

Marrs · #2 05-06-2013, 08:14 PM

Hi, the oil cap pulls straight up, it doesn't twist even though it looks like it should (don't ask how I know or where all my band-aids went). If you look on the back side (firewall end) of the injector pump you will see a cylindrical cap with a thin rod that goes through it, twist it out and there is a small dipstick on the end. This is NOT the knob that has a knurled edge and spring beneath it, leave that one alone. Note: Some injector pumps are fed oil from the engine block, but I believe yours is early enough that it is a sealed unit like my '62. Look at post #3 here to see a photo that explains which one you have. fuel injector pump 250SE | Mercedes-Benz Club of America
The following only applies if you have the sealed unit.

The dipstick will most likely show empty. You can remove the oil with a suction device or just use a straw and drop it in this opening, then put your finger on the end to create suction as you lift it out. There's not much oil in there so it won't take too long. Refill with engine oil. You can refill until the line is reached on the dipstick.

What state are you in? My state, and many others, do not require cars of a certain age are exempt from smog tests since they were not fitted with the pollution control equipment to begin with. Maybe you simply need to register or license it as an "antique" or whatever terminology your state uses if you feel you may not have to meet the smog requirements. Please consider filling out your User CP so it's easier to assist you in the future.

JPMOSE · #3 05-08-2013, 01:57 PM

When you add oil, make sure you screw the red cap all the way to check the dip stick...otherwise you will over fill it.

Benz Dr. · #4 05-08-2013, 09:10 PM

Empty? Not very likely. More often they're way over filled which affects how the pump works.
Two things to look for is a leaking cold start valve and a stuck warm running device. Either will produce a really rich mixture that will foul out a set of fresh spark plugs very quickly. Once the plugs are fouled it won't run at all.
Injectors are very hard to find for this car and they all have to break ( inject ) at the same pressure. This is not an easy system to get to work right.