Hello ,

I took the advice and ordered a set of injectors and glow plugs to remedy the cold start smoke, rough idle and poor fuel economy.
Now, they sent me with each injector a plastic bag with the metal seal and a square piece of paper (1.25" X 1.25") . What is this paper for ?
I will take the intake manifold off, clean everything good, ordered a new gasket for intake also. I will change the fuel return loop lines ( rubber hoses ) for all injectors . I will clean all vacuum lines and valves.
The timing chain and the cylinder head were replaced and have about 25K on them. The trap oxidizer I took off , cut a window in the side after removing the shield, gutted out all the ceramic , welded the window back on and put it back on the engine. According to the dealer records MB had done the campain on this car and it appears the previous owner took the parts off and put a trap back on from another car !!??. Tried to get them to do it again and will not.
After the injector work I will take it in to have the timimg and fuel delivery checked and adjusted properly.
Can someone, please, detail a step by step procedure to do this injector job right ? What is the torque requirement for injectors ? I bought a 27 mm deep socket. Is there a trick to get the injectors to line up nice ?

Thank you.

1987 MB 300D turbo (w124) 6 cyl - 603 engine

(I realized after I wrote all this that yours is a few years later than mine. Since it's not the 616/617 engine then much of this may not be applicable!)

The injectors should be torqued to 75 Nm but the fuel lines from the pump to the injectors take only 20 Nm. Be careful as these will break and leak if you overtighten them. It's hard to torque them if you don't have the special tool - a slotted offset socket that allows you to get around the fuel lines to the nuts. My procedure is to use the open end of a combination wrench (17mm, I think), tighten them until I feel a little resistance. After I get everything back together, run the engine; if fuel leaks out then they need a bit more tightening. It's not the best way to do it but it works if you don't have that offset socket.

I don't know what the paper is for. The washer goes underneath the injector nozzle; it deforms when you torque down the injector and hence is not re-usable if you ever take injectors out again. Off the top of my head, I can't remember if the convex side of the washer goes up or down...

The little rubber plug on the last injector (closest to the passenger compartment) should also be replaced, especially if you damaged it when removing it, which is easy to do.

When I did this job, the most difficult parts were breaking the injectors free the first time (I used a 4-foot-long cheater bar) and finding someone to rebuild them - I had mine rebuilt, didn't buy new replacements.

Good luck,

- Nathan
'83 240D "Steiner"
'00 New Beetle TDI

Hey guys,

Changing the plugs are easy. about as hard to do as spark plugs. Use the proper torque specs. I think 55 lbs or around 80 nMt. I would reference the number on a manual somewhere, haines has it in their book. I turn them in by hand for a couple of turns. Also not the correct position of the washers as you remove the plugs and put them back in the some way. If I can recall the taper side down. Also use MB fuel line and when you buy it buy a little extra they gave me just enough and I like a little room for error. WHile you got all that stuff apart put in new glow plugs while your at it. It wont take that much time since you have the metal fuel lines off. I dont think that the paper does anything so dont worry about that. Make sure that the washers are in the way you want them before you put the injector in. they may shift around. After the job you have to pump the primer a bit to get it bled off. Pump it until the hissing stops. Also the car may make some noise for the first couple of minutes. Tapping noise. I believe that is the return lines filling up or somethings it went away for me. YOu should notice that it runs a bit better. also glow plug the car for 10 before turning the key. The glow plugs are on after the light goes out.

also change the fuel filters out if you havent yet because you have to bleed the engine anyway.

have fun

bob