My 1000th Post was supposed to be a tale of glee not DOOM! Xantia X2 Hdi109 Ongoing Issues

[Rhothgar]

All,

I was saving this post for something special. A story of how the 2.0HDi had been resurrected from over 2 years off the road. A tale of the trials and tribulations.

However, the tribulations are ongoing and it's not driving me nuts.

Car got its MOT in March 2020 and then after my having diagnosed and fixed the corroded ECU pin died as I went to pick it out and drive it home.

So it sat at my friends until the end of June when I finally got around to going to sort it out except I didn't sort it out, it just started again without issue.

I drove it to my brother's (20 miles) then to mine and lent him the car. Within days, the clutch had gone again. I fixed it! It went again. I fixed it! It was sorted. The master cylinder had just not been twisted enough in the bulk head to secure it. All is now fine.

Until...

days later. I get a call off my brother. "It's broken down at the end of the road and I cannot get it started!".

Days later, I managed to make the time to go down. It started then stalled. It started and I revved the nuts off it and managed to reverse at speed up the private road. It then died. I did Lexia it back on 30th June and it came up with many faults. Some permanent, some temporary. I got it to start and it reported around 300 bar pressure before dying. The faults show a reduced pressure of 71 bar.

I read the faults. I think they were the same as the ones from 30th June.

P1112 Temporary Fault. Fuel high pressure monitoring, Lack of pressure (Leak)
P1138 Temporary Fault. Fuel pressure regulator. Short circuit to earth or open circuit.
P1408 Temporary Fault. Fuel Pressure regulator. Short circuit to earth or open circuit.

Main parameters 1
Engine Speed 803rpm
306 bar
Open Cycle Ratio 19%

So let's put the Lexia session of 30th June aside.

Last week, I finally got to go down and take a look again.

I have Lexia'd it again after having to reinstall Lexia again because it only came up with a black screen. (BIG ROOKIE MISTAKE: Forget to enable the Network adapter - 5 hours wasted reinstalling several times!).

No faults cleared from previous session at this point. The car is now starting but only if you crank straight away from key off and it dies with a second of starting. You can only get it to restart if you turn key complete off and then crank up immediately after waiting for 5 seconds with key off.

So I Lexia'd it again and it now comes up with these faults.

P0100 Permanent Fault. Flowmeter signal. Short or open circuit. Flow too low.
P1138 Permanent Fault. Fuel pressure regulator. Short or open circuit.
P1112 Permanent Fault. Fuel high pressure monitoring. Lack of pressure (Leak) 71 bar 97.3% OCR (which is too high).
P1135 Permanent Fault. 3rd piston deactivation. Short or open circuit.
P1408 Permanent Fault. Additional heating circuit. Short or open circuit.
P1403 Permanent Fault. 1 additional heating circuit. Short or open circuit.
P0180 Temporary Fault (YIPPEE!). Fuel temperature signal.

I then erased those faults.

I turn ignition up to start position without cranking and it then reports:-

P1138 Permanent Fault. Fuel pressure regulator. Short or open circuit.

I then crank the car over. It's turning at 225rpm and only producing 47 bar of pressure. Not enough to open the injectors!

I erase the faults.

Ignition off.

Reading faults at each stage:-

Ignition on to accessories.
No faults!
Ignition onto start position.
P1138.
Ignition cranking.
P1138,
P1135,
P1408 and
P1403
All permanent!

I then used an Picoscope Oscillope to read the signal of the fuel pressure regulator. Strange things happening! Supply showing 16V and output only showing 3.75Volts to nothing on cranking. (It should be battery voltage down to nothing on cranking to build the pressure up). I jiggle the breakout leads about and manage to get battery voltage at the fuel pressure regulator and the waveform looks fine.

Today I borrowed a fuel pressure regulator from a mate. No change! If ignition is off and you crank immediately without waiting for transponder light to go it, it fires and dies immediately. Oscilloscope shows fuel pressure regulator waveform as soon as the key starts to turn for 300-350ms then the signal vanishes!

OK, Guys! I'd very much appreciate your input.

Where would you start given the above?

[Rhothgar]

Have I gone over everyone’s heads with talk of oscilloscopes?

Surprised not to have any replies.

Really stuck with this now.

Did a diesel leak off test today. All looks good.

The waveform on the fuel pressure regulator is correct as is the fuel pressure sensor.

I took the return pipe off the fuel filter housing and out my thumb over the housing outlet. Boost pump pressure seems OK. Apparently it should be 2.5+ bar? Engine bay got covered in diesel. Have wrecked my Mum’s drive with removing filter connections over the last week or so.

One dangerous thing I could do failing any advice is loosen off the injector nuts one at a time to see if there is high pressure but I really don’t want to do this as I’d be introducing more air into the system.

I’ve taken the fuel filter out for now and still no change so will leave it out until car starts again if it ever does.

What can cause the car to start and die immediately and not produce a fault code?

EGR valve? Turbo poressure solenoid valve? Engine speed sensor? Inertia switch intermittently playing up?

I am going to clear the fault codes again and do a complete global test.

£500 spent so far and it looks like the car may well still be scrapped. I’ll be gutted if that has to happen.

I hope someone has a bright idea.

[Hell Razor5543]

If you can get hold of him (he is currently bedridden) give citroenxm a PM. He knows what he is on about, and may well be able to help.

Definitely do NOT loosen off the injector nuts. If you were to get hit by a high pressure jet it could be injected into you (even without a needle), as it only takes around 30PSI to force fluid through the skin, and the HDi engines have much higher pressures (if my memory is correct, around 3,000PSI) at the injectors.

[Rhothgar]

I’m not going to touch them. Didn’t realise only 30psi can do penetrate the skin! I think it’s because of the atomisation.

Think I may be onto something.

Accelerator pedal hard spot signal 1 and 2 do. It change when the pedal is pressed?

I changed a couple of electrovalves over too but that made no difference. I jiggled the connector to the throttle sensor and I wonder if that did something because the car started and ran for more than 1 second this evening. Only about 3 seconds but it’s progress in the right direction.

[Rhothgar]

@Hellrazor5543

After all that, I clean forgot your comment about 30psi and I tested the low pressure side by removing the return pipe and placing thumb over housing outlet to feel for pressure. That should run at about 40psi.

Still alive at present...

I think it probably requires perhaps 80-100 psi minimum of atomised fuel to penetrate through the skin to achieve deadly results. Not sure.

[KennyW]

Looking at your faults have you checked the wiring to fuel pressure regulator for continuity. A broken wire could be the problem.The vibration in the engine maybe making it connect then disconnect.

Worth a check doesn't cost money to use a multi meter.

Kenny

[Rhothgar]

Hi KennyW

I believe I've done a load test with an H4 headlight bulb on the wiring. I'll check again just in case and give the wires a waggle whilst doing it.

I've started un-taping the loom but am going to be scoping the camshaft and crankshaft sensors hopefully today at some point and doing a current test on the low pressure pump.

I cleaned the engine speed sensor in the gearbox on advice from citroenxm as the clutch had failed and it could be clagged up. Further investigation may be required in that area if all else fails. He bought a non-runner HDi, blew the dust off that and it ran as right as rain until it departed... No such luck for me last night.

I must be closer to a solution. It just feels that I'm nowhere near though. Very frustrating.

Something is causing the regulator to switch off I think. Don't know if you've been following the story since February but a pin was corroded through on the ECU. Repaired that! Car started and has now died again. I re-soldered that temporary wire with a thicker one this weekend. I seem to recall shorting the in-tank pump out trying to test it with limited diagnostic knowledge back in Feb. It still works but until I do current draw test and volume test I've no idea if it is operating to full capacity.