After a fresh run tonight I got

[stu9]

The P1112 code...."high pressure fuel monitor (leak)

Now I know it'll probably be a hose, but where ?

I thought this Lexia thing was supposed to tell you exactly what and where the fault is, that's what I was told

Ok, so it's maybe a hose...if it's a split or tear, something I see, then fine...if it's a bloody pin hole and only happens when running and under boost (which is when it's cutting out).....I'm fkd!

[stu9]

Anyone....again i was sure after putting this up and 30 vierws later, someone would know.......think i'm on my own now. Infact i might stick to the wee Pug as that site/forum is alot more active

[citroenxm]

Did the the car cut out, or go into Limp mode?

Ive got a more scarey problem in that under hard accelleration the car simply cuts out and stops!! The error I have is "Loss of fuel pressure " .. Im leading to beleve its the engine fuel pump.. as Ive changed all the sensors for known ok ones..

DickieG is pretty good with HDi fault codes.. I would of thought he may have been able to help.

[stu9]

Cut out, but start in a few minutes with eml on but drives as if nothing's happened....till go into turbo again, then the same thing

I though since last night someone would have known too

Dont think much of the lexia kit either btw...if that's the way it works!


It was a waste of time putting it up....in the other thread some said put up the codes, I do and get nothing!

[citroenxm]

Theres not many who have HDi's on here that have experianced faults with them, they tend to be very good!

You have the same issue as my car.. She cuts out, starts after 5 seconds ingnition off and will carry on with EML on...

I beleve it to be the Engine Pump, failing to supply enough pressure at higher revs.. Ive not confirmed this yet as Im yet to get a pump to fit to the car...

I find the lexia rather usefull, if not direct. But certainly does help in areas where you could be days finding a fault..

[RichardW]

We're only enthusiastic amateurs mostly, Stu. Just slapping a fault code up and expecting an "It's XY bit" response within minutes is a bit much In the case of HDi engines, they have given remarkably few problems to date on here, so our experience is a bit thin. The Lexia is a fab piece of kit compared to a generic OBD reader - but it needs time and knowledge to get the most out of it. In your case you need to watch the live data repeatedly for fuel pressure, fuel flow rates, engine speed, anything else you can find in the Lexia to give clues. The fault code is probably being flagged due to a discrepancy on the flow rate into the rail vs the pressure or something. Could be a cracked injector causing a high leak off rate - have you checked the leak off rates? If you have a high pressure leak it will be obvious - the rail runs at 300 bar at idle, rising to 1500 barg at WOT. Do NOT go looking for an HP leak with your bare hand.

[citroenxm]

Richard, he has the same issue as my car.. Cutting out under acceleration.. I have had this for some time now, and tackled it myself due to what you say, no one has had it here..

Ive changed all the sensors for the fuel etc.. still there. Im confidant its a Pump fault... As I said, Ive not got a spare one I know is good to try..

Soon as I have some spare cash to get a pump I shall.. I have no leaks, etc at all.. Its a pressure reading, the only thing that pressures the rail and can cause it to drop out is the Pump as its next down the line. So thats what Im looking at next.

[djadams]

No specific HDI experience, but it could be a clogged fuel filter or other low-pressure fuel supply issue. If the HP pump cannot get enough fuel, it can't generate the required pressure at high flows (high engine speed and high load). Worth checking the filter and if it's not known to have been changed lately giving that a try, I'd say. HP pumps usually pretty reliable for lots of miles if system well maintained and kept free of contamination. They can be quickly trashed by miniscule quantities of dirt though.

[stu9]

We're only enthusiastic amateurs mostly, Stu. Just slapping a fault code up and expecting an "It's XY bit" response within minutes is a bit much

I know, same as me

It's just that a few said to get the codes and put them up, I guess I was expecting them to help....I've also been in in contact with Jim, I've texd him a a couple of times, but now doesnt answer, maybe he's away or busy but I wont hassle him again....so I guess I'm on my own now.

What's pissing me off with the lexia too is that after being told how great it is (and maybe it is) I expected it to be very accurate in the diagnosis and not just sying "high pressure fuel monitor (leak)"...if it said high pressure fuel hose, and said where it was, then I'd have a better idea

[Hell Razor5543]

The thing to remember is that a Lexia is so much more than a simple fault code reader. From what I have been told (and read on this forum) a Lexia can provide live data and trigger various actuators. However, fault codes can narrow down where the problem is (or eliminate where it isn't, which is just as useful). Understanding a Lexia is more an art than a science, but when you do it really is a great piece of equipment. I am intending to get one in the New Year (probably the one the knowledgeable members are raving about, with great aftercare), once Christmas, birthdays, and Gracies' insurance have been dealt with.

[Mandrake]

Depending on the type of fault (particularly partial faults like poor running) I don't actually find fault codes that useful, I find the live sensor data and actuator tests a lot more useful in tracking down faults.

The problem is not the Lexia as such but the the way ECU's log faults, or don't as the case may be. I've had both severe engine running problems on my V6 and gearbox problems, not a fault code between them!

Through good old fashioned investigative work I've found a missing inlet manifold gasket, two broken spark plug leads, a missing hose clamp on the idle control valve inlet hose, and I also believe the oxygen sensor and MAP sensor while not completely faulty are at least somewhat impaired. No fault codes logged despite very poor running, lack of power, hesitation and stuttering under load etc...

The gearbox is changing gear erratically, the lockup clutch seems to be intermittently malfunctioning, (seemingly slipping) and its making nasty noises under load which lead me to believe its days are numbered, no fault codes logged!

Many faults such as oxygen sensor, map sensor and so on typically require a complete failure of the sensor to log a fault code, but the common failure mode for many sensors is only partial failure or inaccurate data. Just because there is no fault code logged for something doesn't necessarily mean it's ok and isn't imparing the running of the car...likewise a single fault code will not necessarily lead to a "replace this part to cure the problem" outcome, but should be considered just as a clue in the troubleshooting process. The Lexia is not going to hold your hand and do the entire troubleshooting and diagnosis process for you unfortunately.

For the problem in the original post I would be going for a ride in the car as a passenger with the Lexia showing live sensor data and watch for any correlations between the behaviour of the car and the sensor data.

[KevMayer]

The pressure output of the diesel pump is controlled by a pressure regulator on the pump outlet. The ECU controls the regulator and the effect is that low pressure is achieved when the regulator is fully open so fuel returns to the tank and high pressure is achieved when the regulator closes up so very little fuel returns to the tank. These regulators can go faulty, but, I'm fairly sure they can be replaced quite easily (famous last words and all that).

[Chlorate]

The lexia is an excellent tool for diagnosing Citroen engine management problems.
Unfortunately as with all engine management diagnostic tools the error codes etc will only only point to what the engine management system "sees", for example if you lose fuel pressure for whatever reason the ECU will likely say "fuel pressure fault" and little else, it won't tell you "fuel filter blocked" or "fuel pump broken" etc.
A lot of over-reliance on diagnostics and the too common knee-jerk reaction of blaming the sensor is quite a problem these days, I recall a recent post here of some chap who had spent a lot of money on a diagnostic session, error codes pointed to the cam and crank sensor, both were replaced but the problem persisted - turns out the timing belt had failed.

But I digress, if you were leaking fuel out of the high pressure system it'd be quite obvious. It could be the pressure regulator dangling off the fuel rail or the sensor itself. Worth plugging the Lexia in again and looking at live readings whilst the car is running.

Alex