Disabling EGR

stumo

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Diesels aren't all that good on really short running at the best of times so this can only make it worse in that regard.
Yeah, that's what I'm thinking.

I mean for normal usage I'd disable the EGR right away no questions asked.

But with our current usage, I'm in 2 minds as to whether the longer warm-up (without EGR) would do more damage, rather than keeping the EGR and hence the faster warmup it provides.

Actually 3 minds....
Maybe for our usage the fuel economy would be better if I kept EGR too. hmmm.

In any case I will go ahead and fit a new thermostat - thanks for all the responses on that. I only ever saw 85 on the dial when it was 45 outside last summer!
 

toby1

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Right! Having a go at the mod tomorrow. Pictures will be taken along the way.

Fingers crossed I can sort this myself :???:
 

toby1

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I think it's worked!

Right gents, after a quick visit to Halfords to grab a few odd and ends, I had a go at this yesterday. Unfortunately I'm not too good with a camera, so apologies for slightly out-of-focus shots, as I think I was too close to the subject.

My electronic engineer friend pre-wired the diode/resistor assembly as I wasn't confident in doing this, plus he has all the bits, so I can't show you what he did as it's covered in heat shrink wrap.

Stage 1: Open bonnet

Stage 2: Cup of tea and a cigarette.

Stage 3: removed the cover of the ECU box (4 Philips screws).

Stage 4: My notes I took off the forum (image wire4).

Stage 5: I relied on Alexander patient's description for wires as I couldn't tally the pin number with the wire going in - so I just went on wire colours. Probably not the best idea but he had the same model so I took the risk.
 

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toby1

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Stage 6: I can see that MAS pin 5 was yellow/white (image wire2). Note the chaffing of all wires into the connector. This could well need attention soon but I don't have the tools to do this so this is one for the garage.

Stage 7: Back to the ECU box. Unplugged the row of plugs and looked for matching wire colours. Image wire3 is plug 2 and I found the 2 wires required.

Stage 8. I don't have a soldering iron or any skills with one, so I took the Scotchlok route. I know these things can be frowned upon but needs must. I connected my pre-wired shunt harness. Image wire5.

Stage 9: Snapped these together and tidied up a bit. Image wire6. Image wire7 just a view from further back.

Stage 10: Locate EGR transducer on NSF inner wing, image wire8, and disconnect, image wire9.

Stage 11: Put the cover back on the ECU box and put my working MAS in, as I've been running around with a faulty one to prevent smoke screens.

Stage 12: Road test. Initial reaction was "great it now revs past 2500 rpm" but what about the smoke?

No smoke to talk about on light load, which is an improvement so once the motor was warmed up, I took it along the A34 for some kickdown tests. Still a fair amount of dark smoke but less than before, so this is probably due to "coking" up plus it's a 99,000 mile motor. I'll stick with it and see if the kickdown smoke lessens, although TBH, this is such an improvement on light load I think this shunt mod has worked nicely.

So big thanks to oigle and everyone on here, dieselman, Alexanderfoti and Alexander Patient and anyone else who assisted.
 

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maxx2it

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Hello everyone,

I am going to make a change in my e270cdi W210, but you can tell me

if the three wires (map, EGR and 12 V) is better that they are completely broken (as he did dieselman) by cutting and welding parts to parts which remain out of the unit leaving the wiring that goes to the engine, or you can just add components to the diagram is not totally cut the wires?

thanks
 

maxx2it

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another question:

in Schedule I of the pins 37 and 50 are the two wires going from the ECU connector to the EGR valve vacuum, then if they cut the wires to fully implement the components
for editing, you need to disconnect the plug on the vacuum valve?
 

toby1

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another question:

in Schedule I of the pins 37 and 50 are the two wires going from the ECU connector to the EGR valve vacuum, then if they cut the wires to fully implement the components
for editing, you need to disconnect the plug on the vacuum valve?

I don't know the answer 100%, I was following oigle's post on page 1 of this thread.
 

maxx2it

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I don't know the answer 100%, I was following oigle's post on page 1 of this thread.

toby, you've done it correctly, why do not you cut the 3 wires but you only have connected the new circuit without interrupting the wiring.

but on the first page is clearly seen from the photos that dieselman cut the wiring and connects to the circuit built.

I wanted to know if it is correct what I read the box mercedes and that is that the pin 37 and pin 50 are the two wires that go from the vacuum unit to the egr valve so if they interrupt the control unit for connecting the circuit I do not need unplugging the connector on vaccum.

than I do as you did, and we do not interrupt the wires connect the circuit with two resistors and the diode.
 

Alex Crow

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you need not cut any wires at all, just make the 3x connections and disconnect the plug at the vacuum modulator.
 
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dieselman

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but on the first page is clearly seen from the photos that dieselman cut the wiring and connects to the circuit built.
I didn't cut any wires, just disconnected the EGR transducer.
 
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dieselman

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No smoke to talk about on light load, which is an improvement so once the motor was warmed up, I took it along the A34 for some kickdown tests. Still a fair amount of dark smoke but less than before,
Try a strong dose of injector cleaner to reduce smoke.
 

alexanderfoti

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Try a strong dose of injector cleaner to reduce smoke.

Also check the swirl flap linkage, when mine comes undone it causes more smoke...
 
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dieselman

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Not trying to be negative, but interested in the advantages of doing this, compared to not doing it.

By the way, I am really impressed by the work you put into this Dieselman, I would never have the enthusiasm to do a similar, although not on this subject !
Being fair, a Guy called Kartech did the investigation.

The advantage is no recirculated exhaust gas, which causes engine problems and reduces efficiency.
 

Alex Crow

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the only real disadvantages will be increased NOx emissions at certain engine speeds/loads. also it is possible that increased exhaust gas temperatures may cause increased wear and tear on eg turbochargers over time, the jury is out on this second point.
 
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dieselman

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Re circulating gas is great for the planet,
Even that is debatable given that NOX is a local pollutant and EGR reduces engine efficiency so more CO2 is produced.
 

maxx2it

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I didn't cut any wires, just disconnected the EGR transducer.

I saw you at the vacuum sensor. but the control unit, where you have the hardware, you cut the wires or you just do not cut the hardware?



you're right I made a mistake .. I thought you had cut the wires from the photo, but you only linked your wiring harness to the car.

the wires that you see in the pictures 2 and 3 are threads that you've added are not the wires of the cable car.

in reality it's not clear from the lack of a photo where you see how to connect cables in your wiring harness to the ECU
 
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