my fap filter is missing ..HELP PLEASE !!

[Homer]

It does represent a material and major change in the anti pollution system which the motor has been certified with, not sure of the legal position

It doesn't matter because you are taxed on the manufacturers figures, not your actual emissions.

The manufacturers figures are based on the same tests as the MPG figues and we all know how accurate they aren't.

[cachaciero]

Hi guys,
many thanks for your replies,its much appreciated, but my original question was if the car will run ok without the fap in line. based on the info you've given me, im happy to do so, but will the ecu sense this and will i need to replace the ecu as ive read this may be the case. any definitive answers please !! the car is in limp mode at the moment, so is'nt drivable. regards Nick

Yes it will run without the FAP. The ECU will not know that the FAP is not present if the pressures across the FAP chamber are within the correct range. There is collectively some doubt about what that is, the differential pressure has to be close to zero but maybe not zero, possibly if it is zero the ECU will "know" that there is no FAP filter and raise an error.
Anyway it should be possible to fool the ECU by stuffing some coarse steel mesh into the FAP chamber to produce a small amount of differential pressure if required.

This may require a degree of experimentation and this is where your problems start.
It seems to me that you don't know the state of the sensor that monitor the FAP, without knowing that this is good and and that the pipes are on the right way around for sure and without access to a Lexia you have no way of really knowing of what is causing any errors that you may see.

Don't believe that FAP / EOLYS errors put the engine into Limp mode except possibly a blocked FAP.

So if the ECU is in Limp mode then you may have other problems.

The car is quite drivable in Limp mode just lacks any performance above about 2500 rpm.

Cachaciero

[wheeler]

Interesting point about the minimum diff pressure I did wonder about that but currently on my car which has a relatively new FAP the Lexia says the diff pressure is zero and there are no warnings. Of course it maybe that the Lexia looks for an offset in absolute terms which it equates to zero. If a diff pressure is required shouldn't be too difficult to stuff a bit of restriction into the empty FAP filter case.

I've checked an almost new (about a week old) FAP differential pressure with lexia & it reads 5mb at idle. Have you checked the pressure difference with the engine under load ? In theory there must be a difference if there is a filter in there. The ECU will only take any notice of of a constant invalid pressure reading & flag a warning. I would agree that it should'nt cause limp home mode unless it was blocked.

[cachaciero]

It does represent a material and major change in the anti pollution system which the motor has been certified with, not sure of the legal position

It doesn't matter because you are taxed on the manufacturers figures, not your actual emissions.

The manufacturers figures are based on the same tests as the MPG figues and we all know how accurate they aren't.

True but arguing the "Devils Advocate" as the tax authority:-

' It is you the owners responsibility to maintain the vehicle to the manufacturers standard. Any material change which you the owner make which takes the motor away from the manufacturers standard and by doing so increases the co2 emissions and hence put the vehicle into a higher tax bracket may if you do not declare such modifications be considered an attempt to defraud the excise. '

Don't misunderstand me those are my words but I bet that something very similar exists somewhere in the excise statutes.

Cachaciero

[reef2k]

thanks for the info and opinions. im hoping that the reason its still flagging a fault is because its not been on a lexia,although it could be that the ecu needs replacing. the pipes on the fap housing were connected up correctly and the sensors look ok,but could be faulty i guess.
the other problem i know of is what i believe is a vacuum solenoid that is mounted to the side of the air filter housing/box. i found one of the inlet/outlet pipes has broken off,and although ive repaired it,the fault is probably still on the ecu,so could be why its still in limp mode. power is very low and its hard work trying to keep up with traffic,and if the monitor is correct,then its only doing 16 mpg. it looks like a trip to the citroen garage for a session as i dont know anyone around here with a lexia.

[cachaciero]

t=
the other problem i know of is what i believe is a vacuum solenoid that is mounted to the side of the air filter housing/box. i found one of the inlet/outlet pipes has broken off,and although ive repaired it,the fault is probably still on the ecu,so could be why its still in limp mode. power is very low and its hard work trying to keep up with traffic,and if the monitor is correct,then its only doing 16 mpg. it looks like a trip to the citroen garage for a session as i dont know anyone around here with a lexia.

If / when you go to the garage to get a Lexia read out tell them that as well as a list of the faults locked into the ECU you also want a printout of the parameter pages for the engine and the Anti Pollution system. They may depending on the garage start mumbling about not producing such things for customers but they are going to charge you for doing the analysis and you have every right to the documentary results of that work.

That way should you have any doubts about what they are saying about the problems and solution you can come back here and post the results for further analysis and opinions.

Oh! and don't tell them that there is no FAP filter fitted.

Cachaciero

[reef2k]

thanks cachaciero, good thinking, i'll do that. its booked in for next wed, regards Nick

[cachaciero]

Nick

I've just re-read this thread and in your first post you said the following:-

bought a C5 non-runner,fitted recon injectors which got it running. diagnostics said particulate filter was blocked,so just removed the whole stainless steel box from below the flexible down pipe ,opened it up and ...nothing, its empty.should this box contain cat and fap ? will the car run without any of these ? i do less than 5k a year,so is there any bodge that'll work ok,money is very tight,so dont want to spend much more on it. i also understand i will probably have to replace the ECU and get it reset by citroen ? would appreciate any help guys, regards Nick

So do I take it from this that you have had it checked on a Lexia or similar before? (....diagnostics said particulate.......)

If so logic would say that if the FAP pressure sensor is piped up correctly and there is no FAP then the sensor (or the ECU) has failed.

There is no doubt that if the ECU "thinks" the FAP is blocked then it will be in permanent Limp Home mode.

It should be possible to disconnect the sensor and replace it with a couple of resistors that emulate the sensor. The sensor appears as a potentiometer to the ECU, one wire is ground one wire is +5 Volts from the ECU and the other wire is the signal back to the ECU. Not sure what the value of potentiometer you need though as the ECU may well expect to see a specific resistance between 5Volts and ground as a way of checking that the sensor is infact connected.

Cachaciero

[corsehf]

Maybe a way around the particulate filter??

http://www.ecuflash.co.uk/DPFRemoval.aspx

[dnsey]

I assume that the pressure sensor is resistive, in which case a possibly more elegant solution than faking-up the pressure differential would be to substitute a resistor of appropriate value for the sensor.