Injector question 300D -1985 - PeachParts Mercedes-Benz Forum

meltedpanda · #1 03-26-2008, 11:26 AM

I replaced all the return lines but still have leaking at the injector base, I have a new set of crush washers. IS this the cure or should I be looking elsewhere, any "gotchas" in this R/R. I have searched and some mention other washers other than these crush washers , are those only used when you remove the injectors?
Suggestions?

winmutt · #2 03-26-2008, 01:56 PM

Fuel leaking at the base or air leaking? Fuel leaking is highly unlikely, that is more likely coming from the injector body not the bottom. If and when you replace the heatshields make *sure* you inspect the prechambers for pintles and glowplug tips.

meltedpanda · #3 03-26-2008, 02:20 PM

Thanks
so best to just pull the whole shooting match, refurbish injectors, replace heat shields, crush washers ----what else???
I figure I am in this far might as well do it right

vstech · #4 03-26-2008, 02:29 PM

if you have never pulled injectors, be SURE you use a large hinge handle/breaker bar, and HIT the wrench, do NOT PULL STEADY pressure, or you will be looking for a PC ring tool...
ask how I know!!!... (thank GOD I have parts cars...)
clean all the gunk out from the injector threads and get the PC seats REALLY clean before you put the heat shields/crush washer (same thing) back in.

pdrayton · #5 03-26-2008, 02:36 PM

Sounds to me like you mean there is fuel leaking from the body of the injector. That happened to mine too when the injector body threads weren't clean when I put them back together, or I didn't put it back together quite right, or the 2 parts of the body weren't tightened enough.

Adding to what vstech said - make sure you screw the injectors in right - I got one cross threaded on my 92 300D and had to replace the PC.

meltedpanda · #6 03-26-2008, 02:52 PM

what do you mean by "hit the wrench" I understand the breaker bar idea, and BTW do I need a special socket or wrench?

winmutt · #7 03-26-2008, 02:56 PM

27mm deep socket. Youll need it for turning the crank as well.

I dunno about hitting it, I've never had a problem. I cant imagine it would fix the problem of someone tightening the injector to the same torque that the pc ring has.

Pulling the injectors, having them poptested and inspecting the prechambers should be one of the first things attended to in any of these cars.

That crush washer is the heat shield.

toomany MBZ · #8 03-26-2008, 04:53 PM

If you just replaced the fuel lines,THEN it started to leak, I would think you didn't get the lines on properly, or you nicked the nipple when removing the old lines. I don't understand how they would just start leaking otherwise.
Good luck.

meltedpanda · #9 03-26-2008, 05:30 PM

no the lines were leaking, and I fixed them and it is definetly wet at the base of two injectors, but it dose not seem to be coming from above, almost like the fuel is pooling around the base

What is a prechamber test?< I am goign to send off injectors to refurb

winmutt · #10 03-26-2008, 05:43 PM

Quote:

Originally Posted by meltedpanda

no the lines were leaking, and I fixed them and it is definetly wet at the base of two injectors, but it dose not seem to be coming from above, almost like the fuel is pooling around the base

What is a prechamber test?< I am goign to send off injectors to refurb

take a bright ass light and shine it in the hole with the heat shields out. you should see a glow plug tip and and underneath it a littke metal light bulb looking thing. If you are missing either you need to pull the prechamber.

Diesel911 · #11 03-26-2008, 05:45 PM

Quote:

Originally Posted by toomany MBZ

If you just replaced the fuel lines,THEN it started to leak, I would think you didn't get the lines on properly, or you nicked the nipple when removing the old lines. I don't understand how they would just start leaking otherwise.
Good luck.

Or, dirt got caugth between the injector and the sealing area of the fuel injector line.

Diesel911 · #12 03-26-2008, 06:16 PM

Where dose is it leaking? The top; 2nd from the top; or 3rd from the top?

toomany MBZ · #13 03-26-2008, 06:17 PM

A leak here is difficult to diagnose, been there etc. I have sworn I had an injector leak, when it was from the lines.
I've also had a leak between the injector parts following advice not to gorilla tighten the two, when replacing nozzles, DO IT.

meltedpanda · #14 03-26-2008, 09:27 PM

911 , going from top to bottom, the bottom most area ( 3rd from top)
Anyone have a complete picture I pulled my manuals but I do not have a good picture for reference.
Do I have this right the injector 911 shows fits into the prechamber and the joint is sealed by the heat shield.( crush washer thingy)? Winmutt you speak of pulling prechamber , is this easy , and then what replace?

Also can the injectors be refurbished and who does it , or do tehy just get cleaned. I used witchunter for my gas injectors but he does not do diesel.

Sorry so many questions , I am new at this diesel refurb, my 84 has been care free.

Diesel911 · #15 03-26-2008, 11:28 PM

Quote:

Originally Posted by meltedpanda

911 , going from top to bottom, the bottom most area ( 3rd from top)
Anyone have a complete picture I pulled my manuals but I do not have a good picture for reference.
Do I have this right the injector 911 shows fits into the prechamber and the joint is sealed by the heat shield.( crush washer thingy)? Winmutt you speak of pulling prechamber , is this easy , and then what replace?

Also can the injectors be refurbished and who does it , or do tehy just get cleaned. I used witchunter for my gas injectors but he does not do diesel.

Sorry so many questions , I am new at this diesel refurb, my 84 has been care free.

Refer to the injector pic in a previous thread.
Sorry I did not have a better picture. If it is leaking in the area 3rd line down from the top it is possible that the upper 1/2 (the gold part in the pic) is loose where it screws into the bottom part (black part with the srew threads). This some time happens when you loosen the fuel injection line nut and it is hard to get the nut off. It is also possible for the black part of the injector (the ijector nut) to develop a hairline crack and cause a leak. The last way you can get a leak in the area if the parts inside the injector are not sealing well (there is no gaskets or crush washers inside). Rust some times eats its way through them and the high pressure of the fuel going through the can some times errode a tiny space enough th leak.

If someone has recently rebuilt the leaky injector you need to return it tom them.
About 1/2 of the black part of the injector goes into the pre-combustion chamber (from the threaded area down).