Nailing getting louder in my '90 300D - PeachParts Mercedes-Benz Forum

quickster · #1 08-08-2008, 06:13 PM

Somebody help me out here. When I first bought the car, it was as quiet as a gasser. The delivery valves were leaking, so I replaced the o-rings and crush washers. It starts to nail. Not that bad; it's quiet next to my Ford 7.3 diesel. I changed out the return lines, filters, and did a purge. Still nailing. It always puffed a little smoke intermitently when cold, but cleared up when it warmed up. So I had Sean Watts do the nozzles figuring it would clear the smoke and maybe the nailing. Just installed the injectors, and it nails louder than ever. And also the smoke that used to go away is still there. Even when warm. I have no leaks, so I'm thinking the timing's out? I scheduled next Wed to get the IP timed. The car has 215K on it, am I overlooking something? BTW, the smoke is fuel. The car doesn't use any oil . Any input would be appreciated. Thanks

compress ignite · #2 08-08-2008, 08:45 PM

When you do the Delivery Valve: O-Ring,Washer,Spring replacement task...

7K and 7G have established a "Lapped" relationship to each other due to
friction over a long period of time.IF AT ALL POSSIBLE they should not
ROTATE in relation to their original position.

ALSO, 7G has the same "Lapped" relationship to the portion of the I.P. in
which it sits...AND should not be ROTATED in relationship to the axis of
the pump.

(And the third and final portion of the "Hat Trick"... 7I the spring should be
replaced at the same time.)

The components may wear into a new "Lapped" relationship over time as they
did originally.

AND the only warning the FSM gives you is "note position".

quickster · #3 08-08-2008, 10:21 PM

I didn't replace the springs...didn't read anywhere that they needed to be replaced. The nailing wasn't too bad after I did the o-rings. I read that crush washers would set in over time as you stated. It's just that the sound is louder now since I did the nozzles. The cold idle is rough, and the smoking doesn't dissipate after it warms up. Not bad, but it's there. I didn't rotate anything below the washer. The springs might have moved a little side to side, but that's it.

Diesel911 · #4 08-08-2008, 10:30 PM

Somewhat the same as Compress Ignite-Here is what I suspect is the problem:
Possible cause of “nailing” after crush washer and "O" ring replacement

Quite a few Members have complained of Nailing after replacing the O-rings or Injectors. Most claimed it went away after severl 100 miles.
If your car has 215K on it and the IP has never been timed it is past due.