New #1 Injector - still nailing - PeachParts Mercedes-Benz Forum

tomm9298 · #1 09-29-2004, 01:13 PM

I just replaced my #1 injector and overflow lines. I am still getting nailing, almost positive still number 1 cylinder. When I crack the fuel line the engine looses power and lopes. But I swear that it is still nailing. Car idles much smoother with new injector. Should I replace the other 4, or are there numerous causes for nailing? Oh yes, I also replaced trans filter, gasket and 6.5 quarts of fluid. (drained torque conv also). But, when I went to Pep Boys to buy the fluid, they have Trans-X for $5.99 with a $5.00 rebate!!!!

Mr. FancyPants · #2 09-29-2004, 01:44 PM

Good afternoon!

Are you still having trouble? Try this: Switch no.1 with no.5 and listen if the nailing follows the injector.

Remember, your chances for getting a non-nailing replacement injector are probably 30% if that!

Steve........

tomm9298 · #3 09-29-2004, 01:49 PM

Good idea.... can't see the forest for the trees. Other than I don't like the sound, is it harmfull in any way, nailing that is? I spent $50.00 to replace one nailing injector with another. Weird thing though, I think a shim came with my new "rebuilt" injector. It is a small washer that fits nowhere on the outside of the injector, so I assuming it is an internal part.

Mr. FancyPants · #4 09-29-2004, 02:02 PM

Hmmm.....very interesting! I wonder if you were supposed to install the shim?

Ya, it would nail if it were missing it's shim washer. Take your new injector to a bench vise, clamp the lower section, the section you had your socket on to extract. Next: use a large adjustable wrench and turn the upper (has only two flats) and turn counter clockwise until you have it appart. Line all the parts on a nice clean rag etc. In the upper half of the injector there is a spring, above that goes the shim.

Clean everything with a clean solvent and lube the needle with wd-40 or diesel, and reassemble. Tighten with a goodly amount of force and return to engine.

If you had to install that washer maybe this was the fault, if not, ???????

leathermang · #5 09-29-2004, 02:04 PM

Better follow up on that shim deal....
I think something important is set by using different shims....
like pop off pressure.... someone who knows will post soon....
EDIT... they posted while I was composing... LOL

79-240d-project · #6 09-29-2004, 02:07 PM

Could it be the heat sheild?

79-240d-project · #7 09-29-2004, 02:09 PM

Oh ya, I think I would have replaced all the injectors. Were they all origional. I got about 230k miles out of mine. I tried just replacing 2 and I still had issues. Once I got all 4 swapped out the difference was night and day. No more heavy smoke on startup, much smoother idle, loads more power, and nailing gone.

Mr. FancyPants · #8 09-29-2004, 02:12 PM

Quote:

Originally Posted by 79-240d-project

Could it be the heat sheild?

I would doubt it is caused by the heatsheild! Leathermang is right about balancing with pop tester, but if it was missing it's shim, it would nail, and might not if reinstalled even if it is not perfectly balanced with the remaining 4.

tomm9298 · #9 09-29-2004, 02:15 PM

I will remove the injector and check for the shim, no it's not the heat shield, way too small. I am not sure if these injectors are original. It has some numbers stamped on it and "France".?.?.??? I have no way to pop test, just an old shade tree mechanic here!! Bloody knuckles and all...

goldenbear · #10 09-29-2004, 02:16 PM

Out of the box rebuilds commonly have issues. You need to take all of your injectors to a diesel injection shop and have them tested for spray pattern and opening pressure. They should all open within 5 bar of one another.

79-240d-project · #11 09-29-2004, 02:17 PM

Quote:

Originally Posted by tomm9298

Good idea.... can't see the forest for the trees. Other than I don't like the sound, is it harmfull in any way, nailing that is? I spent $50.00 to replace one nailing injector with another. Weird thing though, I think a shim came with my new "rebuilt" injector. It is a small washer that fits nowhere on the outside of the injector, so I assuming it is an internal part.

Heat shield?

Hatterasguy · #12 09-29-2004, 03:30 PM

goldenbear said it, don't wast anymore money buying new injectors, take all 5 to a shop and get them tested.

The heat sheilds that come with injectors are very important! They are like a crush washer, what I think they do is keep the nozel in the right position. I know with my car their are 2 one for the original head and a smaller one for ground down heads. You also can not re-use them.

trontek · #13 09-29-2004, 06:15 PM

injector. I just removed my prechamber and th' heat shield was stuck pretty fast to same. It finally worked loose during cleaning & th' groove that th' injector seats into was all gummed up. You either need to clean th' groove out or replace th' shield(best to replace it). Th' only place where there is a shim is under th' lip of th' prechamber. They come in three thicknesses(so I am told) and adjust where th' tip of th' chamber sits in th' combustion chamber.

Someone please correct me if I am wrong as I have been a diesel mechanic for approximately one week!!

Jim

Mr. FancyPants · #14 09-29-2004, 06:33 PM

Quote:

Originally Posted by trontek

injector. I just removed my prechamber and th' heat shield was stuck pretty fast to same. It finally worked loose during cleaning & th' groove that th' injector seats into was all gummed up. You either need to clean th' groove out or replace th' shield(best to replace it). Th' only place where there is a shim is under th' lip of th' prechamber. They come in three thicknesses(so I am told) and adjust where th' tip of th' chamber sits in th' combustion chamber.

Someone please correct me if I am wrong as I have been a diesel mechanic for approximately one week!!

Jim

And I've been a diesel mechanic not too much longer! Approx. 6 mo. Hatterasguy is correct about changing heatshield washers everytime you have the injectors out, however I have gotten away without doing it recently as I had been cleaning and reinstalling. But when my rebuilds arrive (balanced) I have a new set of heatshields to go in.

As far as I'm aware, there is only one thickness size to heatshield washers that go between the injector and PC. The smaller shim washer goes atop the spring inside the upper section of the injector, and that does come in varied sizes in order to set spring tension proper for correct "pop" injection of diesel.

Steve..

Hatterasguy · #15 09-29-2004, 06:38 PM

Check fastlane they list 2 for my car.