EGR bypass on 270CDi electronics

[Robert]

About 3 months ago, the Mercedes garage have done a job on my car and the workshop manager informed me that the EGR is worn and that they (Mercedes garage) have bypassed the EGR by means of a ball in the vacuum line that controls the EGR. I was glad, because I did not have to spend a lot of money on a new EGR valve.

The car performed as usual after start-up, but on average, after every 2nd time you stop, the car was dead and have no power when you pull away. If I drive the car manually, the revs will go up to 4500RPM before it changes to the next gear, therefore I never suspected that the car went into limp mode. I revisited the Mercedes dealer for a computer analyses, but apparently, everything was working 100%. On the lack of power, I was informed that there experience tells them that the turbo needs replacement.

Luckily, I made an appointment at a real mechanic, but work 350km from where I stay. He tested the car thoroughly and listened to what I described and found the problem to be the EGR. When you start the car, there are no faults on the car or his computer, but when you start driving the car, the fault appears and the car's power is significantly less and the car is dead. When you switch off and restart, the fault is gone, but reappears after a while. When we removed the ball, there was two new faults, EGR- and Turbo vacuum pressure to low. We removed the EGR hose and the EGR's diaphragm was torn. The result was that I needed to replace the EGR valve.

I have found a few months back an electronic bypass for the EGR of the 270CDi engine, but never used it. The mechanic suggested that we try it. We bought the resisters and diode (R2-00) and installed it. It is now more than a 1000km later and the car runs perfect. The details are available at:

http://mbworld.org/forums/e-class-w2...sable-mod.html

In my opinion, it works and there are a few advantages more than just saving money for not replacing an EGR valve. I am going to do it on my E270CDi as well.

Robert

[Alan]

Welcome Robert and thanks for sharing.
I'm sure there are some ML drivers who will find this info very useful.

[Andrew]

Or some 290 drivers who complain that some days the 290 just feels "pap".

Freek and I will read that article after we both have chucked out our EGR's

[amzimmy]

Interesting article! I wonder where the EGR is located in my new G300CDI Professional and if this bypass can be done on my engine? ....obviously after the guarantee period is over!
Any suggestions?

amzimmy

[Gelände]

... I wonder where the EGR is located in my new G300CDI Professional and if this bypass can be done on my engine?...

Between inlet and exhaust manifold.

[Robert]

I do not know the G class, but I suspect that the new G class diesel engines will be the same as the other MB CDi engines. On the MB diesels that I know, the EGR is between the inter-cooler and the intake manifold, just before the intake manifold (bolts onto the manifold). I suspect that yours will be there as well, because it feeds exhaust gas into the "fresh" air and logic tells me that you will do it as close as possible to the inlet manifold.

Robert

[amzimmy]

Thanks guys, as always prompt and informative, I will inspect and give some feedback!

amzimmy

[JohnGore]

About 3 months ago, the Mercedes garage have done a job on my car and the workshop manager informed me that the EGR is worn and that they (Mercedes garage) have bypassed the EGR by means of a ball in the vacuum line that controls the EGR. I was glad, because I did not have to spend a lot of money on a new EGR valve.

The car performed as usual after start-up, but on average, after every 2nd time you stop, the car was dead and have no power when you pull away. If I drive the car manually, the revs will go up to 4500RPM before it changes to the next gear, therefore I never suspected that the car went into limp mode. I revisited the Mercedes dealer for a computer analyses, but apparently, everything was working 100%. On the lack of power, I was informed that there experience tells them that the turbo needs replacement.

Luckily, I made an appointment at a real mechanic, but work 350km from where I stay. He tested the car thoroughly and listened to what I described and found the problem to be the EGR. When you start the car, there are no faults on the car or his computer, but when you start driving the car, the fault appears and the car's power is significantly less and the car is dead. When you switch off and restart, the fault is gone, but reappears after a while. When we removed the ball, there was two new faults, EGR- and Turbo vacuum pressure to low. We removed the EGR hose and the EGR's diaphragm was torn. The result was that I needed to replace the EGR valve.

I have found a few months back an electronic bypass for the EGR of the 270CDi engine, but never used it. The mechanic suggested that we try it. We bought the resisters and diode (R2-00) and installed it. It is now more than a 1000km later and the car runs perfect. The details are available at:

http://mbworld.org/forums/e-class-w2...sable-mod.html

In my opinion, it works and there are a few advantages more than just saving money for not replacing an EGR valve. I am going to do it on my E270CDi as well.

Robert

Thanks Robert. I have been reading that EGR bypass post already, but had some reservations. The original guy that "designed" the circuit has left / no longer posts on that forum. Also, some people have not had success (oops), and sometimes one needs more help than that.

I am very glad to hear that someone here in sunny South Africa has been successful with the EGR bypass too.

I have recently bought an old ML (ML270 cdi, 2000 model, w163), and would like to remove the cats, particle filter (some say its too old and does not have one, great!), and delete the EGR.

Another option is to install the UniChip, as that has a feature that can "fool" the ECU into thinking the EGR is working, even when blocked (it modifies the voltage, similar to how this circuit works).

I was wondering if anyone has had success with using UniChip vs this EGR circuit mod? I do not really mind, whichever is easier and cheaper. :P

[Robert]

Hi John

My ML is already fitted with a Uni-chip, but we have bypassed the EGR with the resistors. I really don't know if you can bypass the EGR with the Uni-chip. I have also removed the cat of the car. I was told that the easiest way to remove the core was to cut a hole in the side of the cat's body and then cut the core out and close the hole again. I have removed the cat and used a rod and hammer to break it in pieces to shake it out of the body. It is quite tricky to get the cat out and it took me almost an hour to do the job. You have to remove your air box to loosen the top mountings and I pulled the cat and pipes out from above. I have not cut any part of the unit and only unscrewed all the mounting bolts and removed the two exhaust clamps to get it out. There was a other bracket/part that I have also loosened next to the battery box to get it out, but I cannot recall what it was. I hope this info helps.

I have a copy of the original post with all the detail of where and how to make the connections, if you need it.

Regards

Robert

[JohnGore]

Hi John

My ML is already fitted with a Uni-chip, but we have bypassed the EGR with the resistors. I really don't know if you can bypass the EGR with the Uni-chip. I have also removed the cat of the car. I was told that the easiest way to remove the core was to cut a hole in the side of the cat's body and then cut the core out and close the hole again. I have removed the cat and used a rod and hammer to break it in pieces to shake it out of the body. It is quite tricky to get the cat out and it took me almost an hour to do the job. You have to remove your air box to loosen the top mountings and I pulled the cat and pipes out from above. I have not cut any part of the unit and only unscrewed all the mounting bolts and removed the two exhaust clamps to get it out. There was a other bracket/part that I have also loosened next to the battery box to get it out, but I cannot recall what it was. I hope this info helps.

I have a copy of the original post with all the detail of where and how to make the connections, if you need it.

Regards

Robert

Thanks, that will be great. Pls PM me.

PS: Are you anywhere in Pretoria area?