E300 EGR questions - PeachParts Mercedes-Benz Forum

oldsouth · #1 04-16-2004, 01:00 AM

Hello all, I just purchased a 1998 E300 turbo diesel. Car has about 100,000 miles and is real clean. Just gone through fixing some minor problems and am ready to start on the EGR. I have done a search and spoke to one forum member and have come to the conclusion that no one has yet to disable the EGR on this model. It appears to have more electronic control than my '95 S350. There is an air pump and the throttle is electronic. I am sure if you just disable the EGR, the computer will cut boost like the '95. My question is if, I go the route of changing the wastegate and plumbing to the intake manifold with an inline boost pressure controller like I did on the 350 and in turn bypass the computer, will that work or would the computer disable other functions. Any techs out there care to offer an opinion? I have heard of other members, who have the non-turbo model, plugging the exhaust pipe to the EGR and installing a filter to allow the EGR to operate but with clean air. But that would not work on a turbo engine as boost pressure would be lost out of the filter. I also read this in the shop cd " Oil vapors originating from the oil separator form a coating of oil inside the intake port on the cylinder head and all the intercooling passages. This oil coating lubricates the valve head preventing wear and breakage. A small quantity of oil may collect in the intercooler. It is acceptable that oil may settle in small pockets in the creases of the intercooling hoses (the oil must not be swept away with the charge air stream)." This makes me wonder about routing the blowby pipe to atmosphere like I did on the 350.
Help me folks. Everyone knows how I hate the EGR; but I hate it only because it clogs up the intake. I don't mind the reduction of NoX and the cylinder temps lower. Should I not worry about the EGR and just clean the intake manifold periodically. The car sure runs great like it is. I will get a pix later but by the gps it does 133 mph.

Rick Miley · #2 04-16-2004, 10:26 AM

Hoo boy, lots of stuff to cover here. First off, I don't think the manifold on this engine clogs up as much as previous models, or the TDI. Mine went 80,000 miles before being cleaned by the dealer (gawd know what they did) and never took a performance hit. Even right after the cleaning, I didn't notice a difference at all. So it may be nothing to worry about.

On the oil mist providing lubrication, that sounds like they are trying to come up with something to convince you to leave the CCV in place, but only because the government requires it. But again, the CCV on this engine seems to have a much better oil separator than other engines. I cleaned the intercooler on the TDI at 50K miles and it made a noticeable difference. But the E300 seems to be running fine still at 100K miles without touching it. So I would say the CCV is not a big problem either.

Now back to the EGR. If you really really want it disabled, then there might be an electronic solution. On the TDI Club board they describe a device (Epsilonian or eps) that wires in with the MAF and the EGR to fool the computer into thinking the EGR is working. What the computer is looking for is a corresponding change in flow across the MAF when it commands the EGR to open or close, because air is coming from the exhaust instead of the outside.

Now, the question is whether or not the eps will work on the MB, and to my knowledge nobody has tried. There is a replacement MAF that people (including me) are using on their TDI's that is actually a part for a Mercedes CDI engine. So I'm thinking if the MB part works in the TDI engine, then maybe the TDI eps device will work on the MB. Of course the OM606 is not a CDI, but the part looks physically similar. You'd just have to investigate the wiring.

oldsouth · #3 04-19-2004, 11:55 AM

I did some more research Rick and think I will just leave it alone for now. Boy that engine sure runs fine. And I thought my S350 was peppy.

Rick Miley · #4 04-19-2004, 02:14 PM

I've spent most of the past year driving the TDI and the 240D. After driving the E300 to work this morning, all I can say is

!