Disabling EGR

[zyggy]

ML 270 CDI. 12v- pin37, -EGR Sygnał pin 50 no 60.ALLDATA DIAGRAM INFO.

 

[Rustking]

Update on my problem with the resistor mod om my 270cdi:

I'm now waiting for a new MAF to arrive. I turnd the garbagebin upside down, found the old MAF, sprayed it with electrical cleaner, and mounted it. No codes and no limp. But every 5 minutes or so car will not rev more than 2300-2500 rpm. Classic MAF failure!

Cossing fingers new MAF will sort this problem.

 

[Rustking]

Hopes are high!

 

[Rustking]

View attachment 37339 Hopes are high!

As earlyer posted I have gotten into problems with my egr mod after changing MAF and emptying the cats. After installing the old MAF back, I concluded that the new MAF had to be out of spec.

So buying another MAF did not eliminate the problem completely. Stil gets p1403 and limp if idle for more than 10-15 seconds. No limp as long as revs are more than idle. So whay doesn't it limp with the old MAF?

Have been driving around with the old one for a few days now, and no limp and no code, but it has been frustrating not to know if the car will rev beyond 2300rpm or not, when I step on the gas.

I made another discovery when receiving the new MAF. Febi Bilstein does not make this part, they just put a pierburg one in their packing! So now I have 2 "genuine" replacement parts, likely to come from 2 separate batches.

Putting the cats back on the car is not an option. The car has alot more low end torque. I cruise around in 80 km/h (which is the speed limit here!) at 1800 rpm. And the autotrans goes to 5 gear at 60-70 km/h. I am saving fuel even in limp mode! Top end power is much the same. I did a trip to straight bit of road with a 8% incline to test WOT. From datalog I can see that boost quickly peaks at 1,7 bar but is then reduced and held constantly at 1,4 bar @ WOT. Fueling is reduced once intake air temperature reaches 55C. But this I guess is normal, and is way I need a intercooler upgrade as well.

So I try to figure out what to do next. Maybe get a remap with egr turned down? Any thoughts?

 

[ian lunn]

Hope you sorted but if not consider this, It's something I came across on a golf last year, Some parts (but im not sure if this is one) need pairing to the car"

 

[oigle]

Only comment I can make is that, in normal circumstances, the egr will open slightly when motor is idled for 10-15 seconds. This coincides with your problem. Can't offer any solution but would seriously check all components and assembly of the electronic shunt as that should prevent any opening of the egr and should also prevent the ecu from signalling the maf to change its behaviour. There is a basic fault there somewhere. Maybe a knowledgeable indi like Alex Crow could sort it for you. He is right up there with knowledge on this issue.

 

[Rustking]

Only comment I can make is that, in normal circumstances, the egr will open slightly when motor is idled for 10-15 seconds. This coincides with your problem. Can't offer any solution but would seriously check all components and assembly of the electronic shunt as that should prevent any opening of the egr and should also prevent the ecu from signalling the maf to change its behaviour. There is a basic fault there somewhere. Maybe a knowledgeable indi like Alex Crow could sort it for you. He is right up there with knowledge on this issue.

Yes, and I can not find any information saying otherwise. So I am going to keep on trying to figure this out!

I have had a lot if other things to do lately, so progress have been slow. One often need to put a problem on ice for a while, come back and figure it out!

I post as soon as I have any new development.

 

[bembo449]

just get a remap and have the EGR code removed from the map , did that on my last afla derv for similar reasons to the problem your having , going to do the same on my current alfa too next week , bye bye EGR related fault codes

 

[oigle]

just get a remap and have the EGR code removed from the map , did that on my last afla derv for similar reasons to the problem your having , going to do the same on my current alfa too next week , bye bye EGR related fault codes

The electronic egr delete on this vehicle should be able to do the job for pennies versus very many pounds for a remap. Unless one is getting a remap for other reasons, it is absolutely unnecessary.

 

[bembo449]

if the EGR can be deleted from the standard map I agree entirely pal ?

 

[oigle]

Bembo, If you were to read some of this thread, you would see that it has been successfully done by dozens of members. What Rustking has is not normal.

 

[leonrsa]

In general it's felt that having the EGR (exhaust gas recirculation) system on diesel engines is good for reducing the NOX output but bad in all other respects.
It reduces economy, creates more smoke, increases problems and maintenance requirements due to clogging the intake and can reduce overall engine life.
As a result of wanting greater economy I decided to stop the exhaust gas being recirculated. The problem with doing this on a modern engine is that the EGR valve operation is monitored by the MAF sensor.
The only way to disable the EGR and not trip a fault code and limp home mode is to fool the MAF into thinking the EGR is still working.

On another forum I saw a member Karteck was also looking into this and performing some testing on what resistance values to use to create the required drop in MAF output when the MAF should be operating. He provided the below circuit to use.

The basic circuit for this comprises of two resistors to act as a potential divider and a diode to stop 12v being fed into the MAF circuit.

By connecting into the EGR vacuum transducer activation wire this causes the circuit to only operate when the transducer should be operating the EGR valve.

The standard circuit is a 1k ohm resistor, a 470 ohm resistor and a diode. 1/4 Watt resistors work OK.

The above is for a W210 300TD but the same components should suffice for most applications, but the connections will need to be determined.

First locate the EGR vacuum transducer and disconnect the wiring plug. Using a meter check which wire is the 12v feed and which is the active low signal wire.

Next go to the MAF sensor and again using the meter source the signal wire, which should be Pin5.

For ease of connection trace these wires back to the engine ECU. The easiest way to do this is to disconnect the connector, remove the screw in the back of the connector and prise the connector apart to reveal the wires.
In practice removing the screw and operating the over centre catch will part the connector.

Build the circuit and insulate the components then after locating the appropriate connections (12v, EGR active low, MAF signal) strip the insulation from the wires and solder the mod in place, then make good the insulation.
You will need to disconnect the EGR transducer electrical connection, so ensure you tape it up to stop any water ingress.

The final installation will look something like this, although normally the wires are tucked away by the side of the loom.

The next diagram is for a ML270 just to show the connections. It's the same components, just different ECU connections.

W210 300TD is:

Switched 12v (sorry, can't remember which pin I used)
EGR signal = Pin 35
MAF signal = Pin 21

ML270 CDi:

12v = Pin 37, plug 3
EGR signal = Pin 60, plug 3
MAF signal = Pin 24, plug 4

I think the above will work for all Vacuum transducer type EGR valves, but the connections may vary.

if you try this mod please report back your connections.

Hi Dieselman,
Your images of the circuit is not displaying - can you upload them again? I would like to mod my C270CDI
Thanks, Leon

 

[Rustking]

Bembo, If you were to read some of this thread, you would see that it has been successfully done by dozens of members. What Rustking has is not normal.

That is correct! I'm sorry for having no updates in a while, but it's been busy times reading my family.

I'm still determined to figure this out, just been out of time! I think the problem is simple, so I just need more time to troubleshoot!

 

[monkeh]

Try the exhaust pressure sensor. Just a thought...

 

[Zmay2509]

Hello I have 2001 w203 c220 cdi.
Egr is controlled by vacum and I tried this mod but after about 20-30 min the car lost power, it can go above 3000rpm but its like no boost and kickdown and diagnostic shows egr fault.
Conection are 470omh to maf output (yellow-white) conected to diode 1n4007 the strap on diode is conected to egr negative (yellow-black and I have voltages of 0-12v not only 0 and 12 but 1 2 3 4v.... depend of how mutch rpm) and then i have 1k omh from egr negative to egr pozitiv wire (yellow-white) the tranducer conector is disconected and vacum line is blocked.
Please help me with this problem shoud I get difrend voltages on egr negative is that ok.
I havent removed swirls and my car Maf is replaced and Im geting 2-4 v on output of maf.
Car runs perfect no black smoke lot of power until it goes in "limp mode" no power but revs above 3000rpm.

 

[Dragonml]

Hi
This is my first post
Got my self ml 270cdi mk1 year 2001
From frend who had enough of it.

Long story short,i want to rescue it before it goes to scrap as its not a bad motor.
It had egr fault
2nd had egr is on now ,cleared the code
Drives fine now
I wanted to do egr shunt ,all made up and conected to corect pins
Pins checked to make sure they are correct ones
Maf signal
Egr 12v
Egr signal
But issue started.
With shunt on and vacuum and connecting plug disconnect from egr electrovalve ,car gose in to limp mode vacuum not blocked,
Turbo can not operate vanes ,vanes in closed position all the time,lets say lacking vacuum at turbo electrovalve.

But if i block vacuum to egr electrovalve
Turbo will pull vanes fully open even at idle. If i rev the engine no movment from turbo arm whats so ever, looks like to much vacuum at turbo electrovalve or ecu telling it to open vanes.
Take it all off and clear codes car drives ok.
Has anyone had such issue with egr shunt?
Its a very strange one
Thank you

 

[oigle]

Blocking vacuum to egr is a good idea. Normally just leaving it connected to the disconnected transducer is sufficient but you could have a faulty diaphragm in the transducer so block it with a ball bearing.
Vanes are supposed to be fully open at idle and should stay that way until boost maximises under load and then it will adjust to control max boost level. Just revving the engine will not move the vanes unless under load to produce boost.

Ian.

 

[Benton]

Ive got a 2005 E320 CDI and want to do the EGR delete. I've read through this thread for hours, and I thought i was ready to build the smal circuit, but all the post I read through seem to be for 2003 and earlier. Can someone tell me if the EGR delete for a 2005 E320 CDI is possible. I have it unplugged for now, and I want to prevent the check engine light from being ON. Cheers

 

[oigle]

Wrong method for that motor. Talk to Alex Crow to find correct method.
Ian.

 

[Colin Crump]

Pretty normal for the motor to be a little more responsive after the mod. It will boost quicker at lower revs. You can block the vacuum tube if you wish but, unless the transducer has an internal leak, it is unnecessary.
Looks like you did it right first time

Hi Oigle,
Sorry to resurrect this post I imagine you're sick of talking about it, but would really appreciate it if you could answer a couple of questions.
I have a w169 160 cdi (A Class diesel) and before reading this post recently had the egr cooler, valve and inlet manifold off to remove a huge amount of black crud after 95k miles.
I too decided to delete the cooler, blank the exhaust and feed the egr valve with fresh air from the filter box, but before the MAF, you know where this is going. ......
Yes, I eventually get a CEL which is diagnosed as "low boost pressure".
I can't use dieselman's circuit as the MAF is of the frequency modulated type.
Question: did you try putting a low resistance one way valve in the line feeding fresh air to the egr to prevent back feeding boost pressure to the air box?
Also, does the ECU look for a drop in MAF flow when egr operates at just idle or all rpm, as I don't get any DTCS for MAF volume to high at all, just low boost pressure, this is why I thought of the one way valve.
Really don't want to put the all the original egr cooling and pipework back, one because to do so means dropping the engine again, and two the crud build up.

The only other option would be to use a device from an American company called fuelsave. They do two MAF intercepts, one for variable voltage and one for variable frequency. I'm not sure the device would like to be fed by the modulated egr feed though.
Your input would be greatly appreciated.
Colin