egr bypass 606 turbodiesel - PeachParts Mercedes-Benz Forum

mdisav · #1 03-31-2006, 09:51 PM

After reading a good number of the posts on bypassing the egr on the N/A 606 and also reading how that modification will not work on the turbo 606 (which I agree), I am wondering if together we can come up with something that will work.

Am I accurate in assuming that because a turbo motor will not suck air in on the pressure side, it needs the pressure of the exhaust to have the exhaust enter the intake through the egr valve. So it seems to me that putting an airfilter in place of the exhaust tube even with a check valve ( so that boost is not lost) will not work and will set a code.

Someone mentioned (the guy with the upsolute chips) that he ran a wire from the egr solenoid to the mass air flow on his tdi successfully so a pressure or flow change was registered. But he did not know which one to do on the turbo 606. Maybe this is a viable place to start?

What about directing some of the crankcase ventilation in place of the egr tube somehow? Even if a check valve is to be used? Is the pressure close to or similiar to exhaust pressure? I am thinking it is less but maybe it is enough. I know the crankcase ventilation is on the suction side and it maybe impossible but I am just thinking out loud and throwing out ideas.

Anybody with some ideas? Anyone else been thinking hard about this?

Hatterasguy · #2 03-31-2006, 10:44 PM

My friend did this mod to his turbo charged 606. He did the "fresh air mod" that works on NA 606's. Pretty much put a little air filter on the EGR intake pipe. We got 1/4 of a mile down the street and the CE light came on and cut boost.

However I do not think boost was bleading off through the filter. When we first tested it in the garage their was suction. Makes sense exhuast gas needs to get pulled through that tube.

I suspect their is a temp sensor somewhere. Further study of the 606 FSM is needed. Their is probably a way to trick this sensor.

mdisav · #3 03-31-2006, 10:47 PM

What about the crankcase ventilation idea? It is warm...

mdisav · #4 03-31-2006, 10:49 PM

Maybe it is not a temp sensor but the manifold pressure sensor that is sensing things in the loop. The air filter idea has no pressure increase while the exhaust does and maybe the crankcase might provide.

Hatterasguy · #5 03-31-2006, 10:50 PM

Well that could cause a run away. I would be really carefull about feeding a diesel engine a potential supply of oil like that.

I am just speculating about the temp sensor, I couldn't exactly figure out what is controlling the air intake and the egr. Somehow the MAF is worked into this as well, in that black box known as the ECU. My friend doesn't have an FSM, I need to talk him into one.

I think it can be done, you just have to know how this engine works inside and out to figure it out.

mdisav · #6 03-31-2006, 10:56 PM

I figured that most of the gases would be going the normal route on the suction side and at wide open throttle the egr valve would be closed.

But then again that just may be why the crankcase ventilation is on the suction side. I definately do not want a runaway just trying to fool the egr!

Rafi · #7 04-12-2006, 01:38 PM

I would like to know all the facts please. If you would review the figure and add any information you have then we can see if we can experiment with it. Does anyone know how the pressure conver (53) works ? What does pressure sensor see at what condition etc.

Rick Miley · #8 04-12-2006, 04:33 PM

Routing the CCV to the pressurized portion of the intake tract is a no-go. Max boost is something like 13psi and you would not want to subject your crankcase to that. The engine management computer watches for a corresponding drop in flow across the MAF when it signals the EGR to open. To fool it, you need an electronic device to simulate that change in airflow. That's what the Epsilonian device used on TDI's does. So all you need is someone with the gumption to adapt it to the MB.

That said, the E300 manifold simply does not clog like the TDI does. I've owned mine since new and put 127000 miles on it, and the manifold has only been cleaned once. So it's not really worth the effort to do anything about the EGR.

DR.DIESEL · #9 04-12-2006, 11:24 PM

Quote:

Does anyone know how the pressure conver (53) works ? What does pressure sensor see at what condition etc.

That is a vacuum operated "transducer" or solenoid. It is simply a electricly
operated switch-over valve to actuate the egr valve. When egr isn't needed
anymore, vacuum is vented back out the vent line through the small filter.
I wouldn't recommend tinkering with EGR on the turbo motor due to fuel and
air mapping accounting for it in the IFI engine control unit.
If you trick it into a lean condition, say good bye to the pistons.
The turbo 606's don't suffer from sludging badly when they have good
synthetic oil and clean fuel. Like Rick said, It may only need cleaning
every 100k or when glow plugs head south.
DR.D

#10 04-13-2006, 12:57 AM

Quote:

Originally Posted by DR.DIESEL

If you trick it into a lean condition, say good bye to the pistons.

That's only for gassers, diesels operate lean 98% of the time.

97E300D · #11 04-13-2006, 09:36 AM

Don't give up hope... I was told it would never work on my 97. Although I have to agree the Epsilonian device would be the best solution for the Turbo. And remember raising the combusion temp is a good thing, and that is what will happen without an EGR valve, since it increases the thermal efficency.

W140 S600 · #12 04-13-2006, 01:59 PM

When I tried the fresh air mod for the first time, the engine was still warm and I noticed quite a bit of sludge build up in the egr unit. I had the intake manifold off about <10k earlier and cleaned both the egr and the manifold out. At first I just wanted to test the idea out, so I turned a piece of pipe down on the lathe and attached an air filter to one end, and wedged the other side into the egr pipe that connects to the exhaust manifold. Started it up and let it idle. No problems. So then I took it for a 10mile drive around the area and no lights came on, the car seemed to have a little more pep. I put the car back in the garage and began making a moke permenate fixture to hold the filter in place. Put it on a few days later and with in a few minutes, it poped a CEL light. My guess is that the hot exhaust gases loosens up the build up in the egr valve. When the cooler ambient air comes in through the filter, the dirty egr valve doesnt operate as it should throwing the CEL. Im goin to try this mod again the next time I have time to remove the intake and egr to clean them out. Its the ONLY way to finally tell if this mod works or not.

DR.DIESEL · #13 04-13-2006, 02:53 PM

Quote:

That's only for gassers, diesels operate lean 98% of the time.

That may be true, but I tore down a 99 turbo 606 with a Carlsson
IFI diesel engine modified control unit. The owner was on a long trip
and after 20 minutes on a mountain pass grade the engine let go.
Turns out, the MAF sensor was out of tolerance and reading way off.
It was sending the mixture very lean for the actual boost condition.
On tear down, those cool pistons were melted through.
I don't know what EGT's were or what the boost level of the motor was,
but it was toast and the MAF was off by 40%.
DR.D