C5 not starting

[aneesh84]

I have a citroen C5 II 2005. It doesnt have a DPF. Over the last few occasions I have had a few instances of the engine not starting. These were always after a long drive usually when the car is quite hot. There was no stalling, car worked perfectly, but after a long drive when ignition was turned off, the car refused to start. In all those occasions waiting for 1 hour to let the car cool down would make the car start and function perfectly. I never faced this issue during short city drives.

Yesterday I faced the same problem on a trip and managed to connect a lexia immediately after the car refused to start and got this error:

exhaust gas recycling electric valve control mechanical blockage

even after clearing the error code the car was not starting, but waiting a ten minutes the car started normally and gave no trouble after that.

Any suggestions/help?

[Hell Razor5543]

That suggests the EGR has (as stated) a blockage. You can get cans of cleaner that does work when used properly. Here are a few choices from Amazon;

https://www.amazon.co.uk/s/?ie=UTF8&key ... ysje5cfu_b

[411514]

Were it not for the fault code, the usual suspect for poor hot-starting is the HP fuel pump (assuming that this a diesel). Although this isn't necessarily a common failure, the symptoms are usually as you describe.

[Paul-R]

Presumably the engine spins over without catching. Or are you saying that it won't turn over at all?

[GiveMeABreak]

An you post up your VIN, there's something I'd like to check.

[aneesh84]

it is a diesel. it spins but didn't fire. but other than the occasional starting issue no problem while trying. i wonder if it's the egr why does it happen only when the engine is very hot. usually after climbing a mountain. no it doesn't overheat and the cooling system is working well

[aneesh84]

The VIN is VF7**************[VIN obfuscated, can be read by forum staff]

[GiveMeABreak]

Yesterday I faced the same problem on a trip and managed to connect a lexia immediately after the car refused to start and got this error:
exhaust gas recycling electric valve control mechanical blockage

OK, just checked the engine type from the VIN - DW10BTED4 without FAP
Can your remember the exact error code that Lexia gave?

[aneesh84]

i was a bit worried not to get stranded so i forgot to enter the error and see the details. after i got the error i went to clear it. but even after clearing the car didn't start immediately. next time i will note the details!

[GiveMeABreak]

Clearing the error doesn't actually do anything - if there is an ongoing problem it will simply return until the cause is resolved. Some can be permanent errors and others intermittent. If you get a chance to hook up the Lexia again, come back with the actual fault code.

I'm wondering if it could be the Fuel Temperature Sensor - if this is faulty and is sending the wrong temperature info to the ECU, it may affect the fuelling (like when the choke on older cars was in the wrong position and the engine was warm; it would cause starting issues). It is part 1922 G4 and is 13 on the diagram

Fuel Temp Sensor

[411514]

My bet would be that the EGR fault code is a red herring.

If it were me, I would start with checking battery terminals and power supply to the starter (these can be effected by a hot engine bay). Then check the starter motor itself (the HDi seems quite particular as to cranking speed and if the starter is on its way out the heat from the engine may be enough to reduce its effectiveness). Finally, I would explore HP diesel pump.

[aneesh84]

Today I drove the C5 up a high mountain and then turned off the engine. After that the car refused to fire. No errors were logged. So while cranking i measured the following parameters:

PARAMETERS WHILE CRANKING

Engine speed: 288 rpm
Cam crank synchronization: yes
Fuel pressure reference: 251 bars
Fuel pressure measured: 94 bars
Open cycle ratio Pressure regulator: 48%
Open cycle ratio flow regulator: 40%
Injected flow measure: 12.34 mg/stroke
injector flow correction, cylinder 1: 93.33%
injector flow correction, cylinder 2: 93.33%
injector flow correction, cylinder 3: 97.25%
injector flow correction, cylinder 4: 116.08%
Pre injection advance: -0
main injection advance: -0
injection time: 1.03ms
Engine coolant temperature: 100 degree celcius
fuel temperature: 81 degree celcius
measured air flow: 322 mg/cp
atm pressure: 788 mbar
turbo pressure: 788 mbar
egr valve open cycle ratio : 0%
egr throttle electrovalve open cycle ratio: 10%


After waiting about 40 minutes, the car was still not starting but started after i pressed the accelerator.

PARAMETERS AFTER STARTING DURING IDLE
Engine speed: 736 rpm
Cam crank synchronization: yes
Fuel pressure reference: 243 bars
Fuel pressure measured: 243 bars
Open cycle ratio Pressure regulator: 15%
Open cycle ratio flow regulator: 24%
Injected flow measure: 5.14 mg/stroke
injector flow correction, cylinder 1: 98.04%
injector flow correction, cylinder 2: 91.76%
injector flow correction, cylinder 3: 102.74%
injector flow correction, cylinder 4: 107.45%
Pre injection advance: -0
main injection advance: -0
injection time: 0.51ms
Engine coolant temperature: 85 degree celcius
fuel temperature: 53 degree celcius

Does it help with the diagnosis?