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I have had a brain wave on how to bypass the differential pressure sensor on the 2.2HDi engines, I am desperatley seeking the resistance values of the differential pressure sensor for the particulate filter on a 2.2 HDi engine.

My idea is incredibly simple and I can't believe how long it has taken me to think of it and I need the values to test the hypothesis.

If anyone has these values or has a 2.2HDi and a multi meter and can read them you will doing the world a service. My car is one of the first to have this nightmare system which when the car is shiney and new works fine but many cars with this system will soon be getting to the age when these things start to go belly up.

I could do with a set of values at different revs, e.g. idle, 1500, 2000, 3000, 4000

Quick note to the greenies before I get slated . . . .
I am not looking to remove my filter just bypass the bit that keeps going wrong. My car was MOTed last week and even though my 'Antipollution System Is Deffective' my emmissions were to low to measure.

Stuff the greenies, rip the bugger off, it's what we all want to see done!

you will never be able to bypass the system that way, the exaust pressures are constantly changing with rpm, load, road speed etc..
throwing a variable resistor at it wont change a thing

But doesn't that depend on what the system's actually looking for? If it's got some sort of map to go by then we're screwed, however, if it's only looking for a difference in value in certain ranges (say, normal running<eolys addition<recycle) then maybe it is possible.

Sorry, try that again with my message . . . .

jameslxdt wrote:you will never be able to bypass the system that way, the exaust pressures are constantly changing with rpm, load, road speed etc..
throwing a variable resistor at it wont change a thing

This is the exact point (I didn't mention fitting resistors!) I have had a completely different and much, much simpler idea to get around the problem, people trying to fit resistors are waisting their time unfortunatley as this will never work.

The way they are trying to bypass the sensor is totally flawed. I know for a fact the engine management checks the readings from the sensor before it is started and will throw up an error if it gets a reading it is expecting to see while the engine is running (i.e. if you just stick a resistor on it). This is how it checks to see if the sensor needs replacing (they get gunked up and stick when they get old. The pressure diifrential should also be different at different rev ranges.

Over complicated it a bit by saying resistance values, all I actually need is a list of voltage readings from a multimeter on the sensor at different revs.

Can you tell us your idea Paris or is it top secret

No secret, just sounds too simple but I can't at the moment (until I test the theory) see any reason why it wouldn't work!

what I want to try to do is block the rear pressure outlet and split the front into two pipes and connect both to the sensor. I want to constrist the pipe that goes to the rear side (with something complicated like a jubilee clip) with a small pressure release after the constriction, by changing the amount the pipe is constricted should be able to balance the pressure between to two sides of the sensor until it reads the correct voltage at idle. This will mean the sensor will read right when the engine is off and the pressure diiference 'should' vary natually between the two sides when the engine is revs.

Absolutley no idea if it will work in practice but definatley think it is worth playing with.

Well good luck with it!

OK, really stuggling to get these voltages for testing. Anyone who has a 2.2 HDi engine with a FAP please let me know how much you want to read these values as I am starting to get desperate!