wastegate problems - PeachParts Mercedes-Benz Forum

benzdude42 · #1 09-09-2013, 03:14 PM

i've been working through my vacuum mess and noticed that my wastegate has been missing the vacuum line, easy fix. but now my car smokes more than normal at all temps. could the wastegate have some oil stashed in it thats getting sucked through? i dont care about the smoke, just trying to get a few more years out of the this motor so i can finish up college and buy a rebuild. compression is with in reason, 320psi. what kind of problems am i looking at if the wastegate is unhooked? is this going cut the life of the motor down a lot or just a little?

SD Blue · #2 09-09-2013, 04:23 PM

The line to the wastegate is turbo pressure, not vacuum. It controls the amount of boost to the intake side of the engine and in turn, pressure to the alda for fuel enrichment at the injection pump. For a little less smoke, you may need to slightly turn the adjustment screw on the alda clockwise about 1/4 turn at a time. However, you should first see what the boost pressure is set for on the wastegate.

This link should help with explanation and setup: Mercedes-Benz 126 Service Manual Library

Mxfrank · #3 09-10-2013, 09:06 PM

Quote:

Originally Posted by SD Blue

The line to the wastegate is turbo pressure, not vacuum.

That actually depends on which year and model we're talking about. For example, the 124 2.5's have vacuum operated waste gates, while the very same engine in an earlier 201 would have a pressure actuator. You can tell by where the actuator hose connects...if it connects to the turbo involute, it's a pressure actuator. If it connects to a vacuum switchover valve, it's vacuum operated. I wonder if a punctured wastegate diaphagm could cause this problem.

SD Blue · #4 09-10-2013, 09:30 PM

Quote:

Originally Posted by Mxfrank

That actually depends on which year and model we're talking about. For example, the 124 2.5's have vacuum operated waste gates, while the very same engine in an earlier 201 would have a pressure actuator. You can tell by where the actuator hose connects...if it connects to the turbo involute, it's a pressure actuator. If it connects to a vacuum switchover valve, it's vacuum operated. I wonder if a punctured wastegate diaphagm could cause this problem.

That's nice to know but we're talking about 123/126 series, as per his signature.

benzdude42 · #5 09-11-2013, 12:22 PM

Tuned it down a turn and it was working better. My blow by has become pretty bad sense I got the turbo working. Us it normal to have oil bubble up if I remove the dip stick while running? The only other change is I put a gallon of valonle in my motor before blow by blew up and I added that vacuum line to the intake of the turbo, where air filter meets turbo

SD Blue · #6 09-11-2013, 07:00 PM

Quote:

Originally Posted by benzdude42

Tuned it down a turn and it was working better. My blow by has become pretty bad sense I got the turbo working. Us it normal to have oil bubble up if I remove the dip stick while running? The only other change is I put a gallon of valonle in my motor before blow by blew up and I added that vacuum line to the intake of the turbo, where air filter meets turbo

Something doesn't sound correct to me. Vacuum line to intake of the turbo? Oil bubbling up sounds like pressure building up in the crankcase. Blow by increase with the turbo working? Sure sounds as if a line isn't going to the correct connection. Also, was your oil that low? A gal. of oil is half the engine capacity! Too much oil is very bad news for a diesel engine.

You may need to take some pics to sort this out.

benzdude42 · #7 09-11-2013, 07:13 PM

Well it's lower on oil most the time. Front main took a poop after I went through all the work of doing the rear main and haven't got around to fixing it and no it didn't run out of oil ether. I'll take a picture of my vacuum system later. It will scare you.

SD Blue · #8 09-11-2013, 07:27 PM

With main seals going out, something is definitely building pressure in the crankcase. Especially, when you mentioned oil bubbling out of the dipstick tube.

Either the crankcase venting is blocked, or even more likely, pressure being injected by another source. Or possibly both.