Diesel EGR delete mod

Dieselman

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For some while I've been thinking about stopping the EGR pumping exhaust gasses back into the intake manifold, to stop the intake, valves and piston rings from coking up as well as possibly improving engine efficiency.

For any car fitted with a MAF you can't just block the EGR valve as the MAF detects the reduced airflow when the valve operates. If it fails to report this reduction the ECU throws a code and engages Limp Home mode.
The EGR valve is operated in varying degrees whenever the engine is in cruise mode.

A circuit has to be designed that reduces the MAF output voltage whenever the EGR valve is called to actuate.

Having seen a mod on another forum I decided to give it a go and installed it last night.

The circuit is really simple. The EGR valve transducer is fed with constant 12v which is proportionately shunted to Gnd to create the potential to activate the transducer, so apply vacuum to the EGR valve in varying degrees.

Here is the circuit.



Taken from this thread.
Thanks to KarTek for this.

I used the ECU pin 55 for the constant 12v supply as it was convenient.
Rather than cut the wire from the modulator, I just disconnected the modulator connector for easy reversal, if required. I also blocked the EGR vacuum line for good measure and as absolute proof that it wasn't in operation any more.

I suspect the 12v feed isn't really required if the modulator is left connected instead, with the resistor and diode used to drag down the MAF output on demand.

Having driven 130 miles so far what do I think.?

It appears to work flawlessly with no errors reported. One thing I have noticed is that the EGT temperatures are approximately 50c lower than normal when cruising at 70mph. I believe this is due to the engine drawing cool, fresh air instead of hot exhaust gas.
I'm not sure whether this will improve efficiency or not, but suspect more air is being drawn into the cylinders as a result, so theoretically it should.

It will be interesting to see whether it assists with fuel economy, but the high speed testing last night probably won't help with that..:eek:
 

renault12ts

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Do you think this will apply to any diesel with an EGR, ie 320cdi?
 
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Dieselman

Dieselman

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Yes, but may need adapting to suit electric EGR valves.

Basically the circuit forces the MAF signal to dip about 0.4v when the EGR valve is supposed to be in operation.
 

yachtman

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clk 320cdi
Interesting post

will be interesting to see how much it improves the mpg.

one thought ,does this contravine construction & use regs,afterall turns a euro 3 back to what euro 2 or lower.

In commercials it is an offence to run a euro 4 or 5 vehicle without add blue if it is required. (add blue is part of an after engine exhaust treatment required by most engine manufacturers to meet the eu standards now required)
 
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Dieselman

Dieselman

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one thought ,does this contravine construction & use regs,afterall turns a euro 3 back to what euro 2 or lower.
Technically, probably. But the Cat is still there to keep most pollutants under control, it's just Nox that suffers, so it won't regress back to EuII spec.

If MPG increases the overall volume of pollutant is probably lower, but different.

The Ad-blu is a bit different as that enables the particlate trap to work so is vital to operation.
 
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lynall

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Oh you naughty boy dont go inside the M25 or you will get charged:p

I have always blanked of my egr, on TDI discos it was a case of buy and fit a plate very easy, TD5 engine much cleverer and could tell you had blanked egr, it would store a fault but not put the lamp on.

Wonder how it works on the petrols?, not that it matters as i blanked mine as soon as i got it!

On the trucks Daf and Volvo are adblue and Scanie and i think Man are egr.



Lynall
 

Olivier

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Thank you DM

Today I received the EGR mod made by DM. With the easy instructions that DM wrote me, I was able to put the Mod in place without bother.
The EGR vaccum as been disconnected and I went for a ride on highways, city, country roads and no bother at all, no limping mode. All is good.
The EGR deleted mod work. Now my engine is breathing clean air, not recycled. Yeepee!!!
Again thank you to DM for your time and explainations. You rock :rock:

Happy day to all.
Olivier
 

AANDYY

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Would this mod. be beneficial to us veg runners?
 

alfabm

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do you still do the kits for the egr mod ? if so i would be interested in buying one from you
cheers

Dave
 

jobela

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Am I correct assuming more clean air into the admission/Air filter will improve MPG?
 

jobela

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Please...

I really would apprecioate your help. Does this mod improve MPG?
 

joecud

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hi i have the same problems with my s320 diesel can i install this same mod and where can i get the mod from
 

peapod

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Dear Dieselman,

Your EGR deletion mod looks fascinating, thank you. My car is on its second exhaust the first lasted to 100k a costly item. most runs exceed 20 miles. Will the drop in EGT result in much slower exhaust warm up I wonder ? Also what are all the potential benefits? I guess it must incresase the boost pressure as dilution with hot air is avoided. Is it correct that EGR only operates when cruise control is set? Will appreciate your comments Peapod
 

renault12ts

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Dieselman no longer posts on here so will not be answering your questions.
 

ringway

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That's a shame, he was so helpful in explaining things.

Hope he is ok, do you know if he posts elsewhere?
Yes, he posts on the other side.

Will is a great bloke and his knowledge is phenomenal.

What a great shame it is that he can no longer log on to this forum. :(
 

Sp!ke

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But he can log onto this forum. :dk:

He may choose not to but lets just make that point clear.
 

momomo

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^+1
 

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