Another Non Starter, turns over but won't fire

Questions specifically about a Diesel powered C3 (usually engine or fuel related problems)
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Diesel engine related problems
Think: Diesel engine, diesel fuel system, diesel injectors and glow plugs
My Name: kerabo

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Our C3 16V HDI failed to. start .

It spins over but is not attempting to start.

There are no warning lights on.

I have tried both keys just in case if was the immobiliser .

Checked the cambelt .

Removed and checked every fuse All ok .

The fact its not even smoking says its not fueling to me but it has clean low pressure fuel to the injectors
My Name: kerabo

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Sorry this posted before it was complete. My code reader won't read 2002 its too early. So any common problems. Thanks Ken
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My Name: C3driver52

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Model: C3 2002-2005, Original shape model
Year: 2003 (03)
Engine Size: 1.4 i
Fuel Type: Petrol
Mileage: 79984
Trim Level: VTR+
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Engine name: TU3 (75 PS)
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Hi Ken.
Ken wrote:The fact its not even smoking says its not fuelling to me but it has clean low pressure fuel to the injectors
Its this bit that is misleading you. The C3 Diesel engine is a 'HDi' or 'Common rail'. This system works differently than the previous design diesel engines that has a pump that distributed the diesel to each injector in turn at a (by modern standards) low pressure.

The Common rail is full of very high pressure diesel (that is high enough to be dangerous to people) and this fuel is sent to all 4 injectors constantly while the engine is turning. The injectors are electronically controlled and are fired under control of the engine ECU.


Left: Injector Electrical Signal Connector and Right: Injector Leak-off Connector

Injector electrical connection on a Citroen C3 diesel 16v
Injector electrical connection on a Citroen C3 diesel 16v
The problem I see is that there shouldn't be any low pressure diesel at the injectors, they are fed with very high pressure fuel and you should never see this as disconnecting the injector feeds while the system has pressure (engine running) is prohibited because of the danger of high pressure fuel.

The only place low pressure diesel may appear is the leak-off pipe from the injector, its a plastic pipe and carries the leak-off back to the tank. The trouble with leak off is that its not necessary, but more of a by product of a faulty (leaking internally) injector. More leak off means a more worn out injector.


Testing the leak off quantities can identify the faulty injector.


The point? - too much leak off reduces the pressure in the common rail which operates the pressure sensor, which tells the engine ECU to not fire the injectors because the fuel pressure is too low.

Leakoff:
Citroen C3 diesel injector Leakoff testing results
Citroen C3 diesel injector Leakoff testing results
My code reader won't read 2002 its too early
Yes, the C3 diesel needs to be about a 2004 to read on OBD2. Although I often find a coffee helps me if 'its too early.' The problem is best solved with a Lexia, find out about the lexia/diagbox system here. It will read all 3 models from 2002.
My Name: kerabo

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Joined: Fri Mar 09, 2012 4:30 pm

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Hello and thanks for your reply.
I do understand the common rail system and have noticed on most that if you rotate the engine with pipes off or loose you get primary pressure fuel out. I was asking if there is anyting unique to the Citeron say a Saftey switch it shut down in an accident.

I do see what you saying but its unlikley to loose that amount of fuel through the leak system failing between stopping when running well and the next restart. By low pressure I mean with an injector pipe slack and cranking there is clean fuel shooting up not high pressure as I have a pipe loose. i have since taken this into a local Citeron specialist and he cant solve it although like me his EOBD reader wont talk to a pre 2004. Its been suggested that the ECU may have failed or lost its memory or the imobiliser is faulty but again apart from the low battery light (the battery is charged) No warning are showing. The injector electrical connections look tricky to remove but i have a set of NOID lights that would show if its getting a signal (I dont think it is) but why.
Do you know if the ECU can be used from another vehicle and re programed?

Thanks again Ken

C3driver52 wrote:Hi Ken.
Ken wrote:The fact its not even smoking says its not fuelling to me but it has clean low pressure fuel to the injectors
Its this bit that is misleading you. The C3 Diesel engine is a 'HDi' or 'Common rail'. This system works differently than the previous design diesel engines that has a pump that distributed the diesel to each injector in turn at a (by modern standards) low pressure.

The Common rail is full of very high pressure diesel (that is high enough to be dangerous to people) and this fuel is sent to all 4 injectors constantly while the engine is turning. The injectors are electronically controlled and are fired under control of the engine ECU.


Left: Injector Electrical Signal Connector and Right: Injector Leak-off Connector
Image

The problem I see is that there shouldn't be any low pressure diesel at the injectors, they are fed with very high pressure fuel and you should never see this as disconnecting the injector feeds while the system has pressure (engine running) is prohibited because of the danger of high pressure fuel.

The only place low pressure diesel may appear is the leak-off pipe from the injector, its a plastic pipe and carries the leak-off back to the tank. The trouble with leak off is that its not necessary, but more of a by product of a faulty (leaking internally) injector. More leak off means a more worn out injector.

Testing the leak off quantities can identify the faulty injector.
https://citroenc3owners.com/diesel-citro ... -t314.html


The point? - too much leak off reduces the pressure in the common rail which operates the pressure sensor, which tells the engine ECU to not fire the injectors because the fuel pressure is too low.

Leakoff:
Image

My code reader won't read 2002 its too early
Yes, the C3 diesel needs to be about a 2004 to read on OBD2. Although I often find a coffee helps me if 'its too early.' The problem is best solved with a Lexia
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My Name: C3CAR

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Model: C3 2002-2005, Original shape model
Year: 2002 (02)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 140000
Trim Level: Exclusive
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Engine name: DV4 16-valve diesel (90 PS)
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kerabo wrote: EOBD reader wont talk to a pre 2004
kerabo wrote: I was asking if there is anyting unique to the Citeron say a Saftey switch it shut down in an accident.
Nothing unique that I am aware of. All standard delphi stuff.


A Lexia reader is required for early diesel C3 error code reading.
lexia code reader for all C3 models
kerabo wrote:Its been suggested that the ECU may have failed or lost its memory or the immobiliser is faulty but again apart from the low battery light (the battery is charged) No warning are showing.
There could well be codes stored, without any warning showing. lexia code reader will be my first choice to look for stored codes.

kerabo wrote:Do you know if the ECU can be used from another vehicle and re programmed?
The non dealer way to replace the engine ECU with one that has already been used is to change the whole kit, the BSI, ECU, Keys and Transponder. This removes the need to match the BSI to the ECU as they are already matched. Kits appear on ebay. Reprogramming the injector attributes into the replacement ECU will be required after the switch which is a lexia/dealer job.


I don't think much of your Citroen specialist not having tools to read the fault codes, not really a 'specialist' as OBD2 readers are 'generic'. :o
My Name: kerabo

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Yes I was supptrised he has no reader for it. Like mine his is 2004 onwards But to leave it with a main dealer would cost a fortune. I may have. access to a works Peugeot dealer reader I hope it may read it . Regards. Ken
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