EGR on 606? - PeachParts Mercedes-Benz Forum

slowmoe · #1 08-25-2003, 10:02 PM

I disabled the EGR on my 124. Should I do it on the 210 606 too?

If so, what way is recommended?

DR.DIESEL · #2 08-26-2003, 03:21 PM

Nope. The IFI diesel computer will recognize the loss in MAP
sensor pressure/vac. in the intake and turn on the Check Engine Lamp. Those things are super sensitive to EGR due to OBDII
monitoring.
Sorry but I can't recommend it.
Dr.D

#3 08-26-2003, 04:47 PM

Isn't there a way to delete the software or make an emulator?What about getting a second EGR, placing it in an obscure location, and attaching all the lines to it?

Rick Miley · #4 08-26-2003, 05:01 PM

I'm not sure exactly what Dr. Diesel is saying, but it sounds like the way the VW TDI works. The Mass Airflow Sensor monitors the amount of air flowing into the engine. As the EGR valve opens, it looks for a corresponding decrease in the intake airstream. That makes it extremely difficult to fool, unless you're talking about some electronic mod to the MAS. Good luck figuring out MB's software well enough to do such a thing.

In the "good old days" we could simply block the vacuum line or make a blocking plate for the EGR valve itself. But it seems that the government is onto that trick, and it doesn't work anymore.

LightMan · #5 08-26-2003, 05:01 PM

On TDI's theres a device we call an 'eps' device, which is a vaccum switch with some diodes. YOu disconnect the egr vaccum hose, plug it into the switch. You have to cut/strip one wire to the MAF sensor and hook up the diode device. Basically this device fools the ECU into thinking there is a pressure drop etc when it's trying to activate the EGR etc, and thus causes no check engine light. This would be very easy to install on the 606, I just don't know which MAF wire, and how you determine that. I installed one of these devices on my TDI after removing the egr for off road use, and it works beautifully. Gotta figure out which wire and how that all works.

michakaveli · #6 08-27-2003, 01:10 AM

I would so luv to elliminate that EGR contraption. I assume it would help considerably with soot building up in the intake?

slowmoe · #7 08-27-2003, 09:38 AM

I agree that it would be great to eliminate. But, it sounds as though in order to do this correctly, there is a lot involved.

Is the only down side the build up in the intake? If so can we just periodically clean?

gsxr · #8 08-28-2003, 12:56 PM

Try disabling it and if you have problems, re-connect it. On the 1995 OM606, it can be disabled with no adverse effects. I do not know about the 96-99 versions. It's not a problem on my prehistoric 1980's diesels.

DR.DIESEL · #9 08-28-2003, 06:08 PM

The 96/97 cars use a MAP sensor to determine if egr is doing it's
job. If you tamper with the MAP sensor, the engine cannot tell
what the variable intake flaps are doing since they effect intake
pressures as well. There are constant changes happening with
the mixerhousing flap, intake flaps, and egr valve. Any monkey
business with anyone of these will result in a logic chain fault and
a check engine lamp.
The 98+ turbo cars use a MAP and a MAF sensor to monitior whats going on. They are even more sensitive.

The MB engineers have determined that 90% of the sludge that bulids up in the 94 to 97 606 intakes is from the crankcase vent
system. After shutting down your motor, volitile fumes and oil
vapors pass through all those rubber runner fittings and sit in the intake and coat the wall with thick oil. Coat on top of Coat.
Some cars will even accumulate pools of oil at the very bottom of
the manifold.

Unfortunately, because of our high sulfer fuel in the US, on engine restart, the engine will start pumping egr into the intake at 1400 rpm introducing a large amount of soot to that oil that is allready in there. Presto, instant sludge!

That is why I am a huge beliver in Mobil-1 15-50 and the "Italian
Tune up." Mobil tends to have less vapor after engine shutdown
and it runs to the bottom of the runners, instead of sticking.
Then a good ol' full throttle whompin can blow all of that stuff out of there.
That is why my 1995 E300D has no junk in the intake at
213,000 miles and still drives like new.
EGR hooked up and all!

DR.DIESEL

michakaveli · #10 08-28-2003, 08:31 PM

For giggles I disconnected the hose that controls the first flap, regulating the fresh air coming in and the exhaust gases. Dr. Diesel was right! Check Engine light. Nothing that <100 miles of driving with everything back to normal can't fix. Anywho, having that first flap letting all that air rush made made a noticable difference on pickup, but the higher end was totally gone.

Dr. Diesel

Where is the CCV hose that is coming from out of the head? I was thinking of running a long rubber hose pointed at the ground to ensure that those harmful vapors do not re-circulate and build up sludge. BTW, I do run Mobil Delvac 1 if that helps any....

#11 08-29-2003, 10:28 PM

I have a 1996 E300D with the 606. Similar EGR experience. I had some intermittent problems with hesitations that came upon re-acceleration on the highway (back up to the speed limit from backing off in traffic). It almost seemed like water in the fuel. It wasn't. I read quite a few posts regarding resonance flaps requiring replacement within the intake manifold and air pipe. So I bought some. I never installed them since this forum led me down a different path that could be the problem. It was a test involving the disconnection/plugging of the EGR vacum line. Car ran great with considerable pick-up, but I lost the top-end too. Connected it back up and the Check Engine light went out after about 40 miles. So, I took the EGR off, cleaned it and put it back in. Upon testing I noticed that the external linkage/mechanism for the other "flap"....the one just downstream of the air cleaner.... fluttered sporadically (not smooth) and appeared to stick when I was examining what all these components do as I revved the engine. I just could not believe that this was normal behavior so I cleaned this linkage/mechanism a bit with compressed air and touched a bit of light lube into all the right spots and behold my problem was resolved. So it seems to be quite true that the flaps are all synchronized and that they DO impact performance of the engine. So I will simply maintain the cleanliness of the EGR and this other mechanism as part of my usual maintenance. Seems to be better than trying to figure out some way to disable the EGR and trying to prevent all the monitoring devices and systems from confusion and warning lights, etc. Plus, the EPA could be lurking.

Related: I also noticed quite a bit of soot and some tar-like black goo in the intake ports when I changed the glow plugs not long ago. In no way did it appear to be restrictive so I scooped out what I could at the time knowing that I will want to eventually go back into the intake manifold and clean this out. For the near term, it can wait.

It's no bullet off the line, but it starts great, cruises great and gets 33 mpg.

135kmi
1996 e300d

~ Garrett

DR.DIESEL · #12 08-30-2003, 09:46 PM

To find the PCV system, you need to get to the oil seperator.
Take the big black plastic off the top of the valve cover and you
will see the oil seperator sitting over #5 injector line. you will
also see the big "drain field" of pcv lines heading towards every
port on the intake manifold. 12 of em'. these little rubber fittings
love to crack, leak, plug, fall off and cause general mayhem.
look for fittings that have broken off of the intake.

When I do glow plugs, I remove the intake complete with all of these little hoses installed and just disconnect the big single line
at the black disc oil seperator. I will then remove and replace all of these fittings and clean out the plugged ports in the intake
as needed. I use a steam cleaner to clean out all of the runners
and intake pipes. Do not let the (usually broken) grey injector
line retaining clips fall into the head ports. OR ELSE!!! $$$$$$$
Make sure you drain the oil seperator on the valve cover.
It is held down with 2 10mm hex head bolts.
Try to have your dealer get you a thick paper intake gasket from
a 94/95 606 motor instead of the cheezy thin metal style.

I do not recommend disconnecting these lines or fabricating some kind of "Road Draft Tube". Just use good oil, change it often,
and every 30-50,000 take these puppies apart to clean and degunk as needed.

Have fun
Dr.D

Harvey Gaspar · #13 07-29-2004, 11:49 AM

Dr. Diesel My '97 E300D has 85k on it and yesterday, the check engine light came up. I had noted that the car was hesitating between 1st and 2nd gear and also at highway speed when resuming speed after coasting. (for about a week or so). I took it to Autozone and the tester showed PO 0400, EGR VALVE. I assumed it was correct and so removed the valve to find it fairly gunked up with carbon. Ater a thorough cleaning with Carb Out, I found the vacuum diaphragm was working well, so I re installed and after driving for 20 or so minutes, the cel light went out. It stayed out until I shut down the engine. It showed then but after that was gone until I drove it again this am, when it appeared after about 10 minutes of stop and go driving. I had noted that the hesitations had improved some but not completely at highway speed with coasting and re-acceleration. What's going on? Is it possibly the sensor switch on the egr that is bad?, or maybe the fresh air flap (I call it a choke???). The intake flapper seems to be working well and the little sensor in the rubber intake is now clean and appears intact. If it is the sensor switch in the egr, that is about $330 or more to replace. All help appreciated. Harvey

#14 07-29-2004, 12:31 PM

Dr. Diesel:

Two Questions on my 97 606 with 120K.

Experiencing once every 3 weeks or less a slight engine surge at 70 MPH on the freeway. RPM's increase from 2800 to 3500 or so for 10 seconds. From my thread research I presume it is gunk in the intake and all needs to be cleaned.

Would you concur?

Question 1: Some posts have stated that MOBIL 1 should not be used or is recommended for the 606 diesel? Fact or Fiction?

Question 2: What is your thoughts of changing from regular SAE graded Oil to Mobil 1 in these engines? Problems with potential leaks of seals?

I am a proponent of Mobil 1 which i use in my 911.

I have had the Diesel for four months, and am interested in learning.

TIA

gsxr · #15 07-29-2004, 12:45 PM

1) FICTION.

2) Mobil-1 is highly recommended for all Mercedes engines. 5W-40 is best, followed by 15W-50, with 0W-40 in last place. DO NOT use any of the xW-30 or xW-20 weights.

3) If you search this forum you will find many battles have been fought about oils in general, synthetic OR dino. Do a little reading and you'll find the majority support what I wrote above. To offset the cost, extended drains are possible with oil analysis... I go 10kmi on the 5W-40 (which is repackaged Delvac-1, btw.)