DIY article: W210 DIESEL EGR-disable Mod!

[Lancelot]

Disclaimer: READ people! This article is a compilation/summary of posts on UK-based MB owners forums. All credit goes to 'Dieselman' and 'Oygle' there! Please DO NOT PM me about if this works on car 'X' or petrol engines. I simply do not know!!! I did the below mod to my own car and it works. I DO NOT want to invest any more time and effort in it so please work with the info below. You do this mod at YOUR OWN RISK!!! Neither me, MBWorld.org, or anyone other than YOURSELF can be held responsible for seriously damaging the electronic systems in your car if you don't know what you're doing!!! And before replying, PMing: please READ...people! __________ Mod to disable the EGR on DIESEL engines. In general it's felt that having the EGR (ExhaustGas 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 many owners want 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 Engine Computer (ECU). The only way to disable the EGR and not trip a fault code and limp home mode is to fool the ECU into thinking the EGR is still working. This mod works on earlier TurboDiesel and CDI cars with a vacuum-controlled EGR valve. Check to see if your EGR-valve ONLY has a vacuum-hose connected to it’s BODY. (If the actual EGR-valve BODY has an electrical connection this mod won’t work...) Skills involved are sorting out wires, using a multimeter and handling a soldering iron... Pros: - Less sooth output - Less CO2 output - No more ‘sooth/grease/gunk’- buildup in the inletmanifold (choking the engine) - Smoother and quieter running engine - Fuel economy improves around 2% Cons: - NOX output increases - On CDI engines, warmup time increases. CDI’s have an exhaustgas/coolant-heatexchanger shunted through EGR operation. Take it easy the first few miles (like you should anyways!) How does it work? The Engine Computer (ECU) measures intake airflow using the Mass Air Flow sensor (MAF). This MAF is situated in the airstream right behind the airfilter box. When the EGR-valve is opened, a portion of the exhaust gasses are sucked directly into the inlet manifold (further downstream) so the ECU measures a slight drop in airflow through the air filter box. (the MAF puts out a slightly lower Voltage signal) When removing the vacuum-hose for EGR-operation, or blocking off the EGR valve, the ECU does not measure the slight drop of airflow on the MAF when it operates the EGR and eventually throws an error code and puts the car into limp-home-mode! The ECU will also limp the car when it does not ‘see’ the EGR transducer. (This tranducer controls the vacuum to operate the actual EGR-valve) The Modification: A small circuit (consisting of two resistors and a diode) is hooked-up to the wiring harness going to the ECU. One 1kΩ resistor acts as (the load of) the EGR transducer. Another 470Ω resistor in series with a 1N4004-diode utilizes the control signal for EGR operation to pull the Voltage drop the ECU expects to see on the MAF-signal. That’s all! The ECU is fooled, and the engine still gets the same amount of airflow but it’s all clean air coming through the inlet, getting full boost! The EGR-transducer can now simply be unplugged. This causes the EGR-valve to stay closed at all time. That’s it! No clipping of wires and everything still looks original under the hood. For emissions testing, if needed you can simply connect the EGR-transducer and unplug it again when passed!!! Making the circuit: 1/4 watt resistors are fine as there is no current, just signal voltage. First identify your components. L-R = diode, 470 ohm and 1000 ohm resistors. Solder the 470 ohm resistor to the tail of the diode. Note the silver band on the diode shows which is the + positive blocking. Add the 1k ohm resistor to the other end of the diode and add appropriate wire then clip off any stray tails. Fit heatshrink tubing to the bare sections. And then tape over with material tape for protection to complete. (The Red wire is +12v, Yellow is MAF, Green is EGR transducer signal.) Hooking it up to the car: Please - everyone doing this Mod. DON'T take wire colours for granted. All models are different. Locate the appropriate wire at the MAF using a simple voltage meter. Look for the wire at the maf that indicates a Voltage change in the range of 2 to 4 volts approx. when the engine is Revved. When you have located the wire, note the colours and find the same wire near the ecu. The 12 Volt power source at the ecu of the 300TD is easy to find, once again with a meter, and the wire at the EGR transducer is also simple to locate, once again note the colour at the unit and find it again near the ecu. This is the only failsafe procedure!!! Below are the known connections for W210 300 TurboDiesel and W210 270CDI, W210 320CDI and W163 ML270 CDI. EGR transducer negative side: 300 TD: Pin 35 (grey-green wire) CDI: Plug 3, Pin 50 (grey-black wire) EGR transducer positive side: 300 TD: Any pin/wire that has switched +12V CDI: Plug 3, Pin 37 (grey-red wire) MAF signal: 300 TD: Pin 21 (yellow-white wire) CDI: Plug 2, Pin 24 (yellow-white wire) Inside the ECU box: Hook up the circuit inside this box. It will be insulated and safely dry there! Good luck! A next project will be taking off my inlet manifold and clean out all the gunk that's probably inside. Below a pic of the inlet channels on a OM613 320CDI after 300k KM's...

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[wtb320]

Hi Lancelot,

Thanks for the detailed description ! Especially the pics and the plug and pin numbers !

Works Perfect in my 320 cdi !!!

Greets from Germany


wtb

[andrewmoorey]

Just got the parts from RS, £4 and sufficient to make 10 units, while I am making one does anyone else want one?

[Plutoe]

My guess is that we will be hearing from you very soon!!

[andrewmoorey]

All made up and installed, engine sweet and no error messages
Only differences on my car was EGR pos is red/black, neg is grey/black
MAF signal yellow/white but plug 4 not 2 on my car.
Thanks for the heads up on this one, looking forward to drive to work tomorrow!!

[derekmarinero]

oh, if just I had some knowledge of electrical things to fix it myself
thanks for the info!

[mikepember]

Originally Posted by andrewmoorey

Just got the parts from RS, £4 and sufficient to make 10 units, while I am making one does anyone else want one?

I'd love one if the offer still stands...?

[freakquenzie]

is it possible to buy the parts at ebay perhaps? maybe some extra details about the resistir and diode?

[RobertG]

Originally Posted by freakquenzie

is it possible to buy the parts at ebay perhaps? maybe some extra details about the resistir and diode?

Do you have in your area an electronics supply store?
The op listed the 2 resistors and a diode that you need as well as a diagram.
If you have any friends that play with electronics show them the diagram and they will know what to do.

[freakquenzie]

Originally Posted by RobertG

Do you have in your area an electronics supply store?
The op listed the 2 resistors and a diode that you need as well as a diagram.
If you have any friends that play with electronics show them the diagram and they will know what to do.

hi mate, ye i know how to do the job when i have the parts but there soooo many different diode types and the same with transistors

[autoel_dk]

hi there

does anyone have the missing photos laying around?

please help

[images]

I cant see the pictures can anybody please reup or email me the pictures
thank you
john

[Marko689]

Cant see any pictures. Can anybody help me?
Thanks.

[toby1]

Some pics here: http://forums.mercedesclub.org.uk/sh...ad.php?t=68928

[Marko689]

Many thanks toby1.

[Mr.Billyd]

I read through this and can't seem to find the mod for a W210 606.910 non turbo 97 E300D.
Would you wire it the same as the -98-99 turbos?

Bill

[Plutoe]

I would suggest much more reading as there are big differences between the 606.962 and the 606.910 EGR controls.

[brand55]

Hi there

is it possible to buy the parts at ebay perhaps? maybe some extra details about the resistir and diode.Many Thanks everyone.

[toby1]

Check the link in post 14. The specs are all there.

I have heard that someone might make a kit but nothing concrete.