Peugeot 206 hatchback (1998 - 2006) - 06 1.6HDI FAP DPF Removal Experiment

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Fri 25 Dec 2009 23:09
06 1.6HDI FAP DPF Removal Experiment - schnakvanopen
I have a Peugeot 206 with a 1.6HDI FAP engine, manufactured in 2006, with 68000 miles on the clock. I am aware of the well documented problems that the diesel particulate filter may cause as the car gets older. Filter blocking up, EOLYS fluid needs replacing, forced regeneration / replacement filter etc etc.
To avoid these problems, I am thinking, why not just remove the DPF, maybe cut out the filter inside the can, or replace the DPF entirely with a straight through pipe. I can't find a straight through pipe for sale anywhere, but there is a small exhaust manufacturing company local to me who can fabricate up a straight through pipe relativley cheaply.
The question which needed answering was will the ECU go into fail mode if there is no DPF in the exhaust pipe, and prevent the car from working properly. My hunch was that it should be OK, because the differential pressure sensor that triggers a regeneration cycle, will never register a differential pressure (indicating a blockage), if the 2 small hoses are in free air. My other hunch was that with the DPF removed, maybe the engine will gain a bit of performance with the massive blockage in the exhaust pipe taken out, the exhaust gases can flow a bit more freely.
Only one way to find out, take the DPF out and see what happens. Removing the DPF was much easier than I anticipated. Bit fiddly but straightforward. Once out, the pressure sensor pipes were just hanging in the engine bay. There is also a sensor (a temperature one I am assuming) situated just above the filter in the can, and that stayed in place. So with the filter out, went to start the engine......and no problems at all. No lights on the dash, everything was fine. Went for a drive in it, and it was good. It seemed to me as well to accelerate harder from 2000 to 3000 revs.
My next step is to get a staright through pipe from the back of the turbo down to the main pipe made up and try it with that. I don't really want to cut out the honeycomb filter element inside the DPF, it is too valuable an item for that I think.
Some questions I have no answers for yet, is what the ECU will do when the EOLYS fluid tank runs empty. Maybe I should try removing the magnet sensor in the fuel flap, to stop the EOLYS dosing taking place each time I fill up.
Any comments would be appreciated.

Edited by Dynamic Dave on 26/12/2009 at 00:54

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Sat 26 Dec 2009 00:18
06 1.6 Peugeot 1.6HDI FAP DPF Removal Experiment - gordonbennet
I have no expert knowledge to offer you, but i look forward to hearing how this goes and wish you the very best of luck with it.
What you say makes sense, whether the ECU will agree is another question entirely.

Hopefully others that have these systems will take heart if you are succesful long term and we could end up with a small list of cars able to be so modified...that can only be a good thing.

People are successfully modifying their cars to take common devastating faults out of the picture before they happen....BMW Diesels inlet manifold flaps being one example that works.
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Sat 26 Dec 2009 09:37
06 1.6 Peugeot 1.6HDI FAP DPF Removal Experiment - steve_earwig
I'm surprised you didn't get a fault up the moment the ecu saw the up and downstream pressure sensors were outside design parameters - looks like you got lucky. Removing the magnet will give you a fuel tank open warning, either add a magnet next to it or short the wires. If you get any issues you could try to find someone to change the settings in the ecu so it doesn't look for the FAP. Good luck!

Edited by steve_earwig on 26/12/2009 at 09:38

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Sat 26 Dec 2009 19:29
06 1.6 Peugeot 1.6HDI FAP DPF Removal Experiment - schnakvanopen
With regard to the pressure sensors, and I stand to be corrected, I am sure that it is a pressure differential sensor, in that it does not measure the absolute pressure at the top and bottom of the filter, but only a difference in pressure between the 2.
I have a basic experience of these in my work, and looking at the sensor itself in the car, located near the intercooler front left of the engine bay; it looks like a simple diaphragm differential pressure sensor. If it is, then it will have a rubber diaphragm sheet that is sealed in its housing, on which the pressures act on either side of the diaphragm. A pressure differential will cause the diahragm to deflect and there is an instrument inside that will measure the amount of deflection, and return an analogue signal (4-20mA probably) back to the ecu.
On that basis therefore, I don't think the ECU will know whether there is a DPF present or not; unless it is programmed to recognise the small pressure differential present, caused by a clean filter, which will require an extra amount of complexity of programming, on the ECU, and may even be unmeasurably small.
I don't think the ECU can sense whether a DPF is present, or not, but only to trigger a regeneration cycle when the pressure difference reaches a certain point.
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Sun 27 Dec 2009 09:14
06 1.6 Peugeot 1.6HDI FAP DPF Removal Experiment - steve_earwig
Yeah, ok, it's a membrane (it's not raising a fault so I didn't think anyone would want detail...)

I managed to find some details for you:
There are three connectors - 1. pressure, ranging from 0.5 to 5 volts, 2. earth and 3. +5 volts supply.
Looks like the ECU is meant to raise an issue if the filter is either blocked (0.9 bar, 4.1 volts) or punctured (0 bar, 0.5 volts).
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Sun 27 Dec 2009 13:45
06 1.6 Peugeot 1.6HDI FAP DPF Removal Experiment - dieselnut
'Looks like the ECU is meant to raise an issue if the filter is either blocked (0.9 bar, 4.1 volts) or punctured (0 bar, 0.5 volts).'

If that is the case, your ECU will think the filter is punctured.

You could put a preset potentiometer (say 5k) across pins 2 & 3 with the variable wiper to pin 1.
That way you could set the output voltage anywhere between 0v & 5v.

I suspect the ECU will be a bit more sophisticated & expect the signal to vary, depending on the power output from the engine.

But well worth some experimentation.
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Sun 27 Dec 2009 19:37
06 1.6 Peugeot 1.6HDI FAP DPF Removal Experiment - WorkshopTech
The software on these is quite clever, I dont think a hardware mod will deafeat it.
You need it mapping out of the software, there are people can do this on VAG cars, dont know about Pugs though.
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Sun 27 Dec 2009 23:52
06 1.6 Peugeot 1.6HDI FAP DPF Removal Experiment - steve_earwig
The easiest way is to delete the option from the software, then you can stick the whole lot in the 'bin. There are more and more who can do this for you, for a price naturally.

I have heard of someone replicating the pressure differential with some sort of turbo bleed valve, although I'm not really sure what they meant.
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Tue 29 Dec 2009 19:37
06 1.6 Peugeot 1.6HDI FAP DPF Removal Experiment - schnakvanopen
Thank you all for he information and advice. I hope to have made up a straight through exhaust pipe piece to replace the dpf, in the next few weeks. I will update as to how it goes.
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Wed 17 Feb 2010 21:03
06 1.6 Peugeot 1.6HDI FAP DPF Removal Experiment - schnakvanopen
Following my experiment of running the car without its particulate filter, and proving that the car works well without it. I have had a special piece of straight through pipe from the back of the turbo to the main exhaust underneath, manufactured by a specialist exhaust system manufacturer.
The car works very well with it. It is marginally more noisy at the exhaust exit, but not really noticeable, and there is no more noise inside the car while driving. What is remarkable tough is the increase in performance. It accelerates much harder, and feels as if the engine revs much more freely. It was a relatively quick car beforehand and now more so. Still get 60 to 70 mpg. Very pleased so far.
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Thu 13 May 2010 18:23
06 1.6 Peugeot 1.6HDI FAP DPF Removal Experiment - Raman

Hi, schnakvanopen

Good write up thanks. Just wondering about emissions and passing the MOT?

Any thoughts on that please.

Thanks

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Sun 16 May 2010 12:35
06 1.6 Peugeot 1.6HDI FAP DPF Removal Experiment - dieselnut

By-passing the particle filter will give it similar emissions to other non filter cars.

Schnakvanopen says he has a new straight through pipe from the turbo, so he has also by-passed the cat.

Provided the engine is in good condition it will sail through the emissions test.

There is no difference in the MOT emissions pass standard for cars with or without a particle filter or cat, yet.

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