1981 300SD Excessive Exhaust Smoke - Page 2 - PeachParts Mercedes-Benz Forum

Mxfrank · #16 12-07-2015, 06:32 PM

Quote:

Originally Posted by usmma2013

Update, I had long since disabled the EGR by removing vacuum lines. I did not consider that the valve itself could be partially open. I will install a blocking plate ASAP and see if I notice a change.

The EGR can't possibly account for excess smoke if it's operating properly or sealed off, and my preference is to have it working correctly. It's the least likely cause of any problem. However, have you removed the manifold recently to clean out accumulated deposits? The combination of a leak crank vent and EGR can clog it up with sticky soot.

OtisMagotis · #17 12-10-2015, 03:48 PM

Quote:

Originally Posted by Mxfrank

I've never found this chart helpful, but maybe it will help you.

Thx... according to the chart it also seems to point to injector related

Clemson88 · #18 12-11-2015, 06:35 AM

Quote:

Originally Posted by usmma2013

Thanks Frank!
The air filter I change every 7.5k miles, it's quite clean. The EGR is disabled. I've tried increasing the wastegate opening pressure to 10 psi which helped a small amount but I felt like that was more of a band-aid than fixing the real problem. I do not have to add oil in between changes ever since re-sealing the centrifugal separator and changing to the baffled type breather hose

Update, I had long since disabled the EGR by removing vacuum lines. I did not consider that the valve itself could be partially open. I will install a blocking plate ASAP and see if I notice a change.

Please pardon the ignorance but I have no idea what it is and where it would be located on my 84 300SD.

R-3350 · #19 12-11-2015, 10:57 AM

the centrifugal separator is a round can looking thing in the center of your air filter housing it separates the oil vapors from the blowby gas and returns it to the pan via a tube under the filter housing all you have to do to look at it is take the cover off your filter housing

usmma2013 · #20 12-11-2015, 01:25 PM

Thats correct; on most the plastic lid is loose from vibration throughout the years which reduces the centripedal velocity of the blowby gases and oil vapor. If you bend the tabs and re-seal the plastic top cover with RTV you may notice a difference in oil in the u tube as i did.

Greazzers new injectors should be on the way soon, stoked to install and see what that does for my smoke issue.

ROLLGUY · #21 12-11-2015, 07:36 PM

Have you thought about the turbo shaft seals maybe being the culprit? When a turbocharged engine is idling, the oil pressure is greater than the pressure in the intake tract and cold side of the turbo, and oil from bad seals gets into the intake tract. At boost, the oil is kept at bay because of the pressure in the intake tract. The extra oil would cause the smoke at idle and at low boost. My bet is after a turbo rebuild, the smoking will be gone......Rich

usmma2013 · #22 12-18-2015, 12:27 PM

ROLLGuy,
I rebuilt the turbo a few weeks ago as it was losing oil thru the compressor side.
However, my symptoms are some smoke at idle (occasional visible wisps) and smoke increasing with load/rpm. At low boost/low fuel smoke is not so visible, its only when I'm accelerating or at high highway speeds. I'm certain this will turn to be an injector issue.

usmma2013 · #23 12-29-2015, 03:13 PM

Well I replaced 4 of my 5 injectors today with remanufactured units from Greazzer.

I noticed that 4 of my prechambers looked like this

and one looked like this, with a larger hole. Possibly from a NA engine?

ROLLGUY · #24 12-30-2015, 01:05 AM

Quote:

Originally Posted by usmma2013

Well I replaced 4 of my 5 injectors today with remanufactured units from Greazzer.

You did not replace all 5? Are you planning to do all 5?

usmma2013 · #25 12-30-2015, 10:03 AM

I haven't installed the 5th one as I'm waiting to see if this prechamber needs replaced as well.

biggiefl · #26 12-30-2015, 10:43 AM

I'm having the opposite problem. Was my parents car. I used to be able to stop traffic with soot and now not a wisp. Was wondering if new low sulphur is a culprit mixed with diesel Kleen and 2 stroke oil or my line to the pump may be clogged.

lovedumpster · #27 01-01-2016, 12:29 AM

That 5th one is just missing the heat shield.

vwnate1 · #28 01-02-2016, 01:28 PM

The O.P. here said it's grey smoke not blue nor white , wouldn't oil smoke be one of those ? .

Good discussion , subscribed .

funola · #29 01-02-2016, 01:36 PM

Quote:

Originally Posted by usmma2013

Well I replaced 4 of my 5 injectors today with remanufactured units from Greazzer.

I noticed that 4 of my prechambers looked like this

and one looked like this, with a larger hole. Possibly from a NA engine?

You mentioned replacing the injectors but did not mention pulling prechambers. What you have in your hand is the prechamber ring, not the prechamber itself. Did the prechamber rings come out with the injectors when you removed them? They should not come out during injector removal. If they did, it could explain your smoking problems.