Sudden smoky, shaky idle - Page 3 - PeachParts Mercedes-Benz Forum

#1 01-23-2007, 02:52 AM

Quote:

Originally Posted by bgkast

T3 turbo pushing 15 psi

Maybe that has something to do with it?

bgkast · #2 01-23-2007, 10:57 AM

Nope, because the old one only put out 9-10 psi and the smoking started when it was in the car.

ConnClark · #3 01-23-2007, 11:20 AM

Quote:

Originally Posted by bgkast

I'll check the blow by. Wouldn't the intercooler produce a slight boost pressure reduction and therefore slightly less strain on the head gasket?

The intercooler will produce a slight boost reduction, however you are squishing more air. You will experience more pressure in the compression stroke and the power stroke.

I'd give you some numbers but the web software I used to use is now a pay service.

Do a compression check. If the first cylinder is normal then its not the head gasket.

barry123400 · #4 01-23-2007, 07:40 PM

Perhaps the symptom of your bad idle is being overlooked. I think I would back up and back off one injector line at a time to identify any marginal cylinder if possible first. Or if you like living dangerously scan all the glow plugs from the harness conector with a voltmeter.
I think the cylinder getting the excess oil is going to be hotter or cooler by a noticable margin. That will produce a much different millivolts output than the other four glow plugs. Also do the same test with the engine accelerated to the severe smoking territory if you did not locate the cylinder at idle. What have you got to loose? Also no harm done either.
The valve rubbers do not go down that fast. They usually just fail gradually over a long period of time. You would probably have to go in there and actually remove them to get clouds of smoke on a diesel.
When you locate the troublesome cylinder a little air injected may give you the answer quite easily. If nothing else the millivolt method would locate and identify any individual cylinder if at fault. If the oil were for arguments sake being introduced by faulty turbo seals. The glow plug voltage on all plugs would probably remain pretty constant even with the engine smoking heavy . It just means all the oil is being consumed across the board in every cylinder.
I just added the last item for those that read this and might want to verify for themselves a common source at some point in the future. Or an individual source affecting only one cylinder.

Tymbrymi · #5 01-23-2007, 08:18 PM

Quote:

Originally Posted by ConnClark

The intercooler will produce a slight boost reduction, however you are squishing more air. You will experience more pressure in the compression stroke and the power stroke.

I don't have numbers to back me up or anything, but gut feeling (and I hope some reasoning

) tells me that the higher PSI from compressing more air is small in comparison to the pressure slightly after combustion. I don't think he's turned the fuel up yet, so the BMEP (thus torque and HP) shouldn't have gone up yet...

I do remember you posted a graph on this somewhere... but don't remember where

bgkast, do you have a vacuum pump that puts its exhaust into the intake? Some of the older engines (my SD is like this) have that, and if the vacuum pump diaphram goes bad it will literally pump oil into your intake. I don't think you do, but it is one other thing that is known to cause huge oil consumption problems.

Good luck!!

Tymbrymi · #6 01-23-2007, 08:49 PM

Quote:

Originally Posted by bgkast

My car has suddenly... The smoke is blue-grey and is present at idle. Acceleration after idling ... causes a large plume. ... only recent change was filling up with a few gallons of diesel at a new station, however those few gallons have now been diluted by B99.

Didn't you move farther north recently? It might be bad diesel... Try running it from a fresh container of diesel. Dave M (gsxr here) had this problem which sounds fairly similar. But the car went from Alabama (no winter diesel) to Idaho...

He has some vids...
http://www.w124performance.com/images/cars/93_300D/purchase/bad_fuel1.wmv
http://www.w124performance.com/images/cars/93_300D/purchase/bad_fuel2.wmv

bgkast · #7 01-23-2007, 11:15 PM

I actually just moved slightly south and towards the coast so it is warmer here.

I think I have found the problem...and it is the same problem I thought I already fixed...the turbo oil seals. This is a picture of the new turbo's compressor outlet after 5 miles! (it was clean (relatively) when I installed it. The turbo inlet is clean as a whistle.

Could clocking the turbo or something else cause these leaks or is it just coincidence?

#8 01-23-2007, 11:32 PM

Start it without the IC tube, revv it a bit and see how much oil comes through it

Monomer · #9 01-24-2007, 12:05 AM

pull you CCV hose off.

start the car. put a rag close by the hose's end. See any oil drops? Oil seperators in the CCV system sometimes fail...

atleast, I had this problem.

bgkast · #10 01-24-2007, 03:22 PM

Quote:

Originally Posted by Monomer

pull you CCV hose off.

start the car. put a rag close by the hose's end. See any oil drops? Oil seperators in the CCV system sometimes fail...

atleast, I had this problem.

My crank case vent tubes are clear. Both the one off the valve cover and the one off the oil seperator are oil free.

ConnClark · #11 01-24-2007, 11:14 AM

Its the turbo seals then. Clocking the compressor housing to a different angle should have no effect as it is not in contact with any of the moving parts. To check and be sure, check it off the car. Pull the turbo and block off the oil return passage. Then fill it with oil and apply air pressure to the feed hole.

Tymbrymi · #12 01-24-2007, 08:30 PM

Quote:

Originally Posted by bgkast

I think I have found the problem...and it is the same problem I thought I already fixed...the turbo oil seals. This is a picture of the new turbo's compressor outlet after 5 miles! (it was clean (relatively) when I installed it. The turbo inlet is clean as a whistle.

For others in the thread the attached pic is what it looked like pre-cleaning before it was put in bgkast's car... The car it came off of always had oil in the intake problems (IE, the air filter would get oil soaked, etc).

Could it just be oil that was built up inside the compressor housing? That car didn't use oil (well, certainly nowhere near 1qt/100 miles... ). It didn't smoke or anything silly like that either. I'm not saying the seals aren't bad on this turbo as well... but it sure would be one hell of a coincidence!