2005 ML 270 CDI Disabling EGR Investigated

michael8664

Active Member
Joined
Nov 20, 2012
Messages
41
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Location
Wiltshire UK
Your Mercedes
2005 ML 270CDI W163 Auto, 2002 A160 Auto W168
Took advantage of a gap in the gales to investigate disabling the EGR on my 2005 ML 270 CDI.
Although I had read all 54 pages of this topic there were a couple of points that I got wrong.
For some reason I thought that the EGR and the EGR Vacuum Actuator were one and the same item.
So with the engine cover off I started looking for a small aluminium unit with an electrical plug and of course I couldn't find it.
However, at the front nearside of the engine was a large diameter hose that I
noticed was not quite home in its click-fit housing. I eased the horseshoe spring back, pulled off the hose and peered inside. There was the coked-up shaft of the EGR valve.
I had been completely wrong about the size of the EGR too, I was searching for a unit with a small hose on it.
After that the EGR Vacuum Actuator was easily found, in my case on the passenger compartment nearside bulkhead, actually in full view with the engine cover on.
The MAF was next to identify, found on the offside front of the engine.
Next off were the fusebox and ECU covers to trace the wires.
I'll count the plugs from left to right facing the windscreen.
The left plug (no lock on it) has to be pulled out to allow the next plug's lock arm to swing free, and the same for the next one etc.
The first locked plug (2nd from left) only had up to 40 pins and I was looking
for 37 and 50.
The next plug (3rd from left) had pins 37 and pin 50 so I was in business.
As in other reports the Yellow/Black and Red/Grey wires were twisted together.
At this point bad light stopped play so I didn't investigate the ECU end of the
MAF wire, in my case Brown/White at the MAF end.
Looking at the images in earlier posts in this thread I will need to look in the
first locked plug, 2nd from left in my numbering scheme, for pin 24.

When I do actually do the mod I will take images and post into the main Disabling EGR thread.

Regarding the increased warm-up time, which is not a problem for the Australian expert (oigle), I'm wondering about an active bypass, either with a time delay of say 5 minutes, or with actuation from a suitable existing thermo switch. This would need to be done competently to avoid reliability issues!
 

mobcat

Member
Joined
Aug 10, 2015
Messages
13
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0
Location
st leonards
Your Mercedes
ml270 cdi nov 2001 gl320 2009 sl 560 1989 CLS 350 2009 SL 350 1970
I think its a fair call mate regarding the confusion locating items on your ML when i finally get the shunt to work 100% on my ML i will try and do a step by step procedure of how to do this on a ML with a youtube link i think its the only way to make it easier for a ML 270 cdi given that MB forums limits the photos you can provide regarding how to do the mod.
Cheers
Michael
 

giuseppe

Senior Member
Joined
Mar 22, 2009
Messages
659
Reaction score
8
Location
Bournemouth
Your Mercedes
E220Cdi avantgaurde 2001
I believe they are numbered from right to left, from the wing inwards.
 

turbopete

Senior Member
Joined
Feb 4, 2009
Messages
14,209
Reaction score
331
Age
48
Location
Spennymoor
Your Mercedes
2017 '17' Ford Mondeo 2.0TDCi ST Line X 180 (sorry)
Took advantage of a gap in the gales to investigate disabling the EGR on my 2005 ML 270 CDI.
Although I had read all 54 pages of this topic there were a couple of points that I got wrong.
For some reason I thought that the EGR and the EGR Vacuum Actuator were one and the same item.
So with the engine cover off I started looking for a small aluminium unit with an electrical plug and of course I couldn't find it.
However, at the front nearside of the engine was a large diameter hose that I
noticed was not quite home in its click-fit housing. I eased the horseshoe spring back, pulled off the hose and peered inside. There was the coked-up shaft of the EGR valve.
I had been completely wrong about the size of the EGR too, I was searching for a unit with a small hose on it.
After that the EGR Vacuum Actuator was easily found, in my case on the passenger compartment nearside bulkhead, actually in full view with the engine cover on.
The MAF was next to identify, found on the offside front of the engine.
Next off were the fusebox and ECU covers to trace the wires.
I'll count the plugs from left to right facing the windscreen.
The left plug (no lock on it) has to be pulled out to allow the next plug's lock arm to swing free, and the same for the next one etc.
The first locked plug (2nd from left) only had up to 40 pins and I was looking
for 37 and 50.
The next plug (3rd from left) had pins 37 and pin 50 so I was in business.
As in other reports the Yellow/Black and Red/Grey wires were twisted together.
At this point bad light stopped play so I didn't investigate the ECU end of the
MAF wire, in my case Brown/White at the MAF end.
Looking at the images in earlier posts in this thread I will need to look in the
first locked plug, 2nd from left in my numbering scheme, for pin 24.

When I do actually do the mod I will take images and post into the main Disabling EGR thread.

Regarding the increased warm-up time, which is not a problem for the Australian expert (oigle), I'm wondering about an active bypass, either with a time delay of say 5 minutes, or with actuation from a suitable existing thermo switch. This would need to be done competently to avoid reliability issues!

i did the mod on my C220 cdi and to be honest, the difference in warm up time wasnt something i really noticed it may have taken an extra mile or 2 to get to temp but in all honesty, a thermostat failing would cause a longer time delay to get to temp and would have no adverse effect on overall reliability at all. even in the depths of winter, with temps at -4, (and a failed heater booster) i would start the car, leave it idling (to demist windows etc) whilst i scraped the ice etc off, then drive the 4 miles to work. the temp guage would still read around 50 when i got there. which was more or less exactly what it used to read before the shunt was carried out
 

Dogfish

Senior Member
Joined
Sep 16, 2013
Messages
415
Reaction score
10
Location
South of England
Your Mercedes
CL203 C220 CDI SE Sports Coupe. 2002.
Does the ML have the same extra water circuit and thermostat on the front of the radiator that the C220's seem to have?
 


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