Thanks for the above,DickieG wrote:As follows;citroenxm wrote:Thats ok to test if you have appropriate equipment and details to test them, but when you haven't...
Good post DickieG, interesting to keep in mind next time I have an HDi playing up.
paul
PS: Incidentally, what methods of test did you do??According to the Citroën diagnostic manual for Xantia HDi's, fault code 1112 is a major fault which should illuminate the diagnostic warning light, has that occurred? The fault relates to fuel high pressure monitoring.howiedean wrote:I had a diagnostic check done today and it returned a 1112 code + (glow plug curcuit code also, poor starting problem?) which supports the above.
The list of items to check in relation to that fault are as follows;
-Fuel pressure too high (greater than 1450 bars) check the fuel pressure sensor and the fuel pressure regulator (seizure risk)
-Fuel pressure too low;
Lack of fuel
Clogging of the fuel filter
Check the fuel high pressure pump and the diesel injector return flow ( a diesel injector in good condition has a slow dripping return flow)
-Fuel pressure regulator control too large (Open Cycle Ratio >93%)
The fuel pressure regulator is unable to maintain the fuel pressure;
List of possible faults as above.
-Fuel pressure regulator seized; replace.
-Lack of pressure;search for any possible internal or external leaks.
-Fuel pressure too high; check the fuel pressure sensor and the fuel pressure regulator (seizure risk).
To test the fuel high pressure sensor with the ignition switched on (ECU connected) check the supply voltage between contacts 1 and 3 in the supply connector which should be between 4.8 - 5.15 Volts.
To test the fuel pressure signal voltage;
Connect a voltmeter between contacts 1 and 2 on the same connector ignition switched on;
Engine stopped 0.5 V
Fuel pressure sensor disconnected 5 V
With the engine running the signal pressure should vary between 0.3 V and 4.7 V.
To test the fuel pressure regulator on the high pressure pump;
Connect an ohmmeter between the two pins on the regulator where you should get a resistance of 2,3 ohms.
Check the continuity between terminal 50 of the engine ECU and terminal 1 of the relay 1304.
After the ignition has been switched off, the injection ECU controls the opening of the fuel pressure regulator. The engine should drop from 500rpm within 1.5 seconds. Otherwise the fuel pressure regulator is considered as being faulty (this was happening to the Picasso I mentioned above).
I appreciate the information above and will have a look, the diagnostic warning light illuminates then goes out after the engine has been running for a while. The engine will only cut out if the car is accelerating hard above 2500 rpm, to get it to start again it can take a few seconds.
I decided to change the tank pump as it was starting to fail, that is occasionally no output at the fuel filter. I then suspected the ignition relay for the engine cut out however it looks like I may have two faults as the diagnostic reader displayed a Glow plug circuit error (the temp was near freezing and the car took a couple more seconds to fire up).
Reference the items I have changed / looked at:
Fuel filter
Filter housing (from scrappy £5)
Fuel pressure sensor (from scrappy £14)
In Tank Pump (confirmed failure and it had done 100000 miles)
ECU removed and reseated
Various plugs disconnected / reconnected
HP Fuel pump and regulator (not yet arrived £60)
My view was that the cost of the various scrappy items that I've replaced have been a fair bit cheaper than getting a lexia check done. Generally unless you have spare sensors for diagnostic swaps then a mechanic will suggest replacing expensive items until they find the right one anyway.
The other problem that I have found is that with the car stationary it will not cut out regardless of how many revs you give it, therefore it needs to be on full boost which is when the car is demanding full fuel pressure.
Thanks for your replies, I will keep you informed as I progress through some of DickieG 's checks!!
Regards
Howie