CDI3 EGR bypass mod

Alex Crow

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OK, this works on a W211 with CDI3 electronic EGR valve and 648 (IL6 320 cdi) engine.

It satisfies EGR monitoring function over various driving conditions, and also prevents EGR valve open circuit/short circuit etc fault codes.
On road test the car performed very well, with no black smoke but plenty of acceleration on demand, as said, no codes are being logged during mixed road test and period of idling.

What does it do?

R3 gives a path to ground to 'drag down' maf signal voltage as per earlier CDI2 mod. The diode again is also as per the other mod, and prevents the circuit from raising the maf voltage above its natural value.

R1 satisfies the monitoring of the EGR valve, to avoid open circuit codes.

R2 is a balancing resistor, and has a value chosen with the gain of the transistor in mind, to ensure the transistor is fully saturated when on.

The transistor is used as an inverter, to reverse the PWM signal.

The mod should cause no damage to any electronic components on the car, the max current that can flow is through R3, limited to 18ma or so.
 

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Alex Crow

Alex Crow

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Here is the prototype, using 1k ohm and 1.8k ohm resistors in series to make the 643 ohm required.

Will make a kit up for a willing volunteer, will supply and fit FOC.
Volunteer will understand no liability for any problems caused by the mod can be accepted.
 

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alexanderfoti

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Is this engine essentially an om613 with piezo injectors?
 
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Alex Crow

Alex Crow

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very much the same as a 613, main difference is electronically controlled turbo and EGR valve, as opposed to vacuum controlled.

EGR function monitoring is essentially the same though - open/short circuit monitoring of actuator and mass air flow monitoring are on both types.
 

alexanderfoti

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Ah fair enough thanks :)

If I had the 648 I would volunteer :)
 

amb67

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I have an S211 with the OM648 engine, but before committing my car as a test bed can you clarify a few points, please?


  • Will this look like your pictures below or are you going to build it all in to a discreet loom?
  • Is this something I can fit/remove myself, I am technical and I can solder if required?
  • Is it going to involve cutting or changing the existing loom in anyway?
Relatively happy to allow my car to be a guinea pig and provide detailed feedback. However I do relatively little mileage in my car and it is generally short hops around the village or to town, possibly a good subject car given the nature of this modification.

If you want to talk about this or need anything from me then PM me and I'd be happy to supply my phone number to discuss further.

Thanks

Here is the prototype, using 1k ohm and 1.8k ohm resistors in series to make the 643 ohm required.

Will make a kit up for a willing volunteer, will supply and fit FOC.
Volunteer will understand no liability for any problems caused by the mod can be accepted.
 
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Alex Crow

Alex Crow

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  • Will this look like your pictures below or are you going to build it all in to a discreet loom?
  • Is this something I can fit/remove myself, I am technical and I can solder if required?
  • Is it going to involve cutting or changing the existing loom in anyway?

1. NOOOO!!!! it will not look like the pictures :D. I would recommend fitting it in the ECU housing as this is a better temperature than the engine bay, and away from any moisture etc.

2. Yes, you could (hard for me to guess on others competence...), and I could supply wire colour and pin details.

3. No cutting required, just baring of conductors and soldering on of wires piggy back. Naturally you would need to insulate these connections with PVC tape or similar. The only thing needing to be disconnected is the EGR valve itself - simple plug.

The pictures merely show the test bed 'breadboard' with components installed. It was considered easier to use the breadboard to establish resistor values etc. The mod will be small and neat, with 4x wires exiting it. 3x connect to the 3x wires that go to the EGR valve, and one to the Maf signal wire. As said, all these connections will be piggy back, and all made in the ECU housing (far away from prying eyes).

Ideally I would be able to check any test car for fault codes before and during the use of the mod. If you cannot make it to my workshop that is not ideal.

Also note I am now jetting off on holiday, back to blighty on 11th August, but will probably be on the forum during that period.
 

amb67

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I'm willing to fit this to my car, I can occasionally still get access to a Star machine for fault code reading/resetting and would be happy to email you the print outs etc... as you require.

Technically I am very competent working on my car, I was a technician with Honda and TVR for many years before taking a desk job.

Let me know if you can't get any one closer as a test bed, my offer still stands.

Lastly, have a great holiday.
 
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Alex Crow

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I'm willing to fit this to my car, I can occasionally still get access to a Star machine for fault code reading/resetting and would be happy to email you the print outs etc... as you require.

Technically I am very competent working on my car, I was a technician with Honda and TVR for many years before taking a desk job.

Let me know if you can't get any one closer as a test bed, my offer still stands.

Lastly, have a great holiday.

sounding good to me.

makes sense for me to make the mod adjustable, probably on circuit board, the resistors might need tweaking.

nice to see your enthusiasm, will push forward to get a sensible kit together in August, WTS.
 

AdamG

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Has there been any update on the egr mod?

I have an om648 cdi3 car that I would like to disable the egr.

I'm about to place an order with farnell for the components but was wondering if there has been any changes in the parts required?

I have a star machine so can test for any fault codes.

Thanks

Adam
 
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Alex Crow

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i now have the project box and circuit board to make a neat job of it, just don't have the time!
away again later this week so it will have to wait even longer - probably early September OK Alan?

Adam, it is happening, perhaps you would be happy to hang on until Alan has had it fitted for a week or two? as i said, R3 value may need tweaking.

Also had another look at it, should be able to make it work without a transistor, that might be MK II...
 

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Alex,

Any updates on this. Very keen to try in on my CDI3 e270
 
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Alex Crow

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proper paying work getting in the way!

new tidy box of tricks is 3/4 done (i do have a witness - oarsman), as soon as i get chance we will be ready to go.
 

amb67

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Sorry guys completely forgot about this until it just popped up in the new posts section.

I'm still OK for this but work is kind of taking over my life and I'm probably not going to be able to do this until November. I have a family holiday planned for October and don't want to be tampering with the car so close to the trip.

Has anyone else stepped forward that's nearer to you and willing to assist in testing?
 
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Alex Crow

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no sweat alan, plenty of takers!!
 

NACHO_COOPER

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Hello.

I'm new in this phorum. Excuse me for the language. I have a W211 E280CDI V6. I don't know what kind of motor i have. I recently have to change the particle filter in the exhaust.
I'm very interesting in eliminate the working of EGR.
The electronic scheme, could does it work in my modell?

Thanks very much.

Nacho
 
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Alex Crow

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the short answer is probably not, as you have 2x airmass sensors.

it might work if you double up the diodes (one for each sensor) and tweak resistor values.
 

NACHO_COOPER

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the short answer is probably not, as you have 2x airmass sensors.

it might work if you double up the diodes (one for each sensor) and tweak resistor values.

OK. I would wait for something who make it for his vehicle. I have not access to a star diagnisis machine :(.

If i could access to a machine i make the cirucuit, is very easy and without a cupper boarf can be make it very fast.

Alex,

whe you said tha to obtain a 643 resistance put them in serie, you coud say parallel? because resistances in serie are added the individual value and in paralell was the sum of inveres? because the electricity in the car is continues, not? not altern current? Is only a doubt i have.

Excuse for mi poor english. :(

Thanks very much
 
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Alex Crow

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.....when you said tha to obtain a 643 resistance put them in serie, you coud say parallel?.............

yes yes, so sorry, i did mean in parallel, just a silly typo i am afraid.
 

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