Injector 4 open fault - water found to be dripping onto injector

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My Name: SHK53

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Posts: 4
Joined: Sat Mar 13, 2021 4:35 pm
Model: C3 2002-2005, Original shape model
Year: 2005 (05)
Engine Size: 1.4 i
Fuel Type: Petrol
Mileage: 43000
Trim Level: Desire
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
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Car has been v reliable for its entire life till now, failed a few times with Injector 4 open fault. Rainwater found to be dripping onto inj 4 today after seeing its a common design fault on this helpful forum. Both washers sealed to bonnet with clear silicone and engine bay side of bonnet. Water found on injector and nearby. Injector plug looks mint inside but injector pins very slightly corroded especially near back of the pins - cleaned up meticulously and sprayed with fully evapourating solvent, left to dry, inj resistance was 12 ohms, - reassembled. Car ran fine for a few miles and parked up. When returned to have another test journey fault came on and engine would not run properly at idle. Car has done 43K miles. When it failed recently and RAC recovered it, it was after a short journey that it would not run properly after being parked up. But after a delay because of the recovery the car then ran up ok and was driven up the recovery vehicle.
Although the inj plug looks mint it could be corroded inside where the cables meet the pin sockets, it looks sealed up and not accessible? I could do with a schematic to check continuity & resistance of wiring loom to No 4 inj pls?
Thanks.
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My Name: Ozvtr

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Joined: Wed Jul 10, 2019 3:31 am
Model: C3 2002-2005, Original shape model
Year: 2003 (53)
Engine Size: 1.4 (8v)
Fuel Type: Petrol
Mileage: 80000
Trim Level: Other
Gearbox: Automatic PRND
DPF: No
LHD or RHD: RHD
Engine name: TU3 (75 PS)
Location: Brisbane, Australia.
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Hi and welcome to the forum.

I have found the following site helpful for circuit diagrams however it's in french and the diagrams are a bit small.

http://www.c3manuel.com/injection_allumage-151.html

If you provide your VIN Arfur might supply a more clear diagram.

Just asking, but do you know the cylinder numbering is from flywheel to crankshaft pulley?
My Name: SHK53

Member
Posts: 4
Joined: Sat Mar 13, 2021 4:35 pm
Model: C3 2002-2005, Original shape model
Year: 2005 (05)
Engine Size: 1.4 i
Fuel Type: Petrol
Mileage: 43000
Trim Level: Desire
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Been thanked: 2 times

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Thanks for your reply, I know that No 4 inj is adjacent to timing belt side. Vin is VF7FCKFVB27250425 . I am thinking of testing resistance of No 4 inj when hot but in situ, seeing as it runs okay from cold for up to 10mins, and was the same when it broke down and had to be recovered. No 4 is reasonably easy to get to in situ. fault codes stored: P1336,Misfiring
P0300,Random / multiple cylinder misfire detected
P0204,Injector Circuit Malfunction - Cylinder 4
Thanks.
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My Name: Ozvtr

Moderator
Posts: 936
Joined: Wed Jul 10, 2019 3:31 am
Model: C3 2002-2005, Original shape model
Year: 2003 (53)
Engine Size: 1.4 (8v)
Fuel Type: Petrol
Mileage: 80000
Trim Level: Other
Gearbox: Automatic PRND
DPF: No
LHD or RHD: RHD
Engine name: TU3 (75 PS)
Location: Brisbane, Australia.
Has thanked: 36 times
Been thanked: 250 times

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Try swapping the #4 injector with one of the others. If the fault moves you will know its the injector. If not then it will be the wiring.

If it fails when hot it sounds like the insulation on the injector coil wire is breaking down.

If that's correct I don't think you will be able to test the injector. It will need voltage across it and current flowing through it, a multimeter wont do it. The other thing is that being a coil, when switched on and off, a large voltage (called back EMF) will appear across the coil and this causes the insulation to break down. Again, a multimeter wont simulate these conditions.
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My Name: Arfur Dent

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Model: C3 2002-2005, Original shape model
Year: 2002 (52)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 100000
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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Ozvtr wrote: Sat Mar 13, 2021 9:24 pm Hi and welcome to the forum.

I have found the following site helpful for circuit diagrams however it's in french and the diagrams are a bit small.

http://www.c3manuel.com/injection_allumage-151.html

If you provide your VIN Arfur might supply a more clear diagram.

Just asking, but do you know the cylinder numbering is from flywheel to crankshaft pulley?

TU3JP Injection - Injectors to ECU diagram


Citroen C3 TU3JP Injector to ECU diagram
Citroen C3 TU3JP Injector to ECU diagram
injector_to_ECU.png (39.07 KiB) Viewed 228 times


32V is a 32 Way plug, GR is Grey (Gris) - 32Way Grey Plug on ECU




power is from the engine bay fuse box (BSM) on pin 16 - wire marked in blue (its the wire that disappears off the page in the diagram above)


Citroen C3 TU3JP Injector power supply
Citroen C3 TU3JP Injector power supply
TU3JP_Injection_power_supply.png (30.05 KiB) Viewed 226 times
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My Name: Ozvtr

Moderator
Posts: 936
Joined: Wed Jul 10, 2019 3:31 am
Model: C3 2002-2005, Original shape model
Year: 2003 (53)
Engine Size: 1.4 (8v)
Fuel Type: Petrol
Mileage: 80000
Trim Level: Other
Gearbox: Automatic PRND
DPF: No
LHD or RHD: RHD
Engine name: TU3 (75 PS)
Location: Brisbane, Australia.
Has thanked: 36 times
Been thanked: 250 times

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Thanks Arfur.

Looks like 1331 is injector 4. 1332 is injector 3 and so on.

In the rubberized pre-formed injector loom pin 1 of all the injectors is common power. Pin 3 of the 6 way connector is power in, so pin 3 is connected to all the number 1 pins of the injectors.
Pin 2 of injector #4 goes to pin1 of the 6 way connector. Pin 2 of injector #3 goes to pin2 of the 6 way connector. Pin 2 of injector #2 goes to pin5 of the 6 way connector. Pin 2 of injector #1 goes to pin6 of the 6 way connector. Pin 4 is unused.

The rest of the wiring is apparent in the circuit diagrams.

Hmm its funny how all the wire and pin numbering points to 1331 being injector #1 but its in cylinder #4!? Silly French people. :D
My Name: SHK53

Member
Posts: 4
Joined: Sat Mar 13, 2021 4:35 pm
Model: C3 2002-2005, Original shape model
Year: 2005 (05)
Engine Size: 1.4 i
Fuel Type: Petrol
Mileage: 43000
Trim Level: Desire
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Been thanked: 2 times

Post

Thanks for the info , I would have thought 1331 was inj 1 moving along to to 1334 being no 4? Another more generic question am I right in saying I can pull ECU connectors out with the batt connected providing the ignition is off? I think so. Also if I trace it to an injector any makes that are recommended or ones to avoid? I presume no programming is required for a new injector.
Thanks,
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My Name: Arfur Dent

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Posts: 3303
Joined: Sat Jul 23, 2011 3:47 pm
Model: C3 2002-2005, Original shape model
Year: 2002 (52)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 100000
Trim Level: Exclusive
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Engine name: DV4 16-valve diesel (90 PS)
Has thanked: 258 times
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SHK53 wrote: Sun Mar 14, 2021 3:56 pm I presume no programming is required for a new injector.
You are correct, no programming is needed to add or swap injectors.

Another more generic question am I right in saying I can pull ECU connectors out with the batt connected providing the ignition is off?
Yes, the ignition system is powered down so it is safe to disconnect them with the ignition off.
You can add an avatar to your account - Avatar or change your vehicle details - Car Bio or even add a signature to your posts - Signature. But this is not all you can do in the User Control Panel :)
User avatar
My Name: Ozvtr

Moderator
Posts: 936
Joined: Wed Jul 10, 2019 3:31 am
Model: C3 2002-2005, Original shape model
Year: 2003 (53)
Engine Size: 1.4 (8v)
Fuel Type: Petrol
Mileage: 80000
Trim Level: Other
Gearbox: Automatic PRND
DPF: No
LHD or RHD: RHD
Engine name: TU3 (75 PS)
Location: Brisbane, Australia.
Has thanked: 36 times
Been thanked: 250 times

Post

SHK53 wrote: Sun Mar 14, 2021 3:56 pm Thanks for the info , I would have thought 1331 was inj 1 moving along to to 1334 being no 4?
On that french C3 site it shows the location of the injectors. 1331 is in cylinder #4 and so on. Go figure.
SHK53 wrote: Sun Mar 14, 2021 3:56 pm Also if I trace it to an injector any makes that are recommended or ones to avoid?
LOL! I had 2 injectors blocked in my car when I bought it. That's why they sold it cheap, they didn't know what was wrong. Engine barely propelled the car.
I got a set of 4 cheap Chinese injectors off Ebay and installed them. Kept the 2 good original ones and salvaged the orings off the others.
About a month later the engine began to act up. Just slightly "missing" at highway speeds. Like you "indeterminate misfire" no clues but I suspected the injectors.
I replaced the injectors one at a time, with one of the original injectors. Laborious, as the injector only failed at high RPM and only sporadically. So I had to run the car between changing the injectors to see if it worked! Guess which injector it was? The fourth injector! Not injector #4 the last injector I swapped! :lol:
Salvaged the orings and threw it in the bin!

What can I say? Original injectors blocked by internal failure. Cheap Chinese injector fails too. Sorry, you will have to draw your own conclusion. However the cost of 4 Chinese injectors is 1/2 the cost of one original!
My Name: SHK53

Member
Posts: 4
Joined: Sat Mar 13, 2021 4:35 pm
Model: C3 2002-2005, Original shape model
Year: 2005 (05)
Engine Size: 1.4 i
Fuel Type: Petrol
Mileage: 43000
Trim Level: Desire
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Been thanked: 2 times

Post

UPDATE: Injector problem fixed with thanks to members on this forum and a video on UTube where at the end the mechanic mentions to check the injectors when warm for open circuit as that is when they fail. It did not take long and a minimum of tools to change No4 injector and reassembly was even quicker. It took me longer to diagnose and replicate the fault than to actually change the injector. I found out it would fail or run very rough after getting to full working temp then at 10 mins after stopping engine then trying to restart, not 2mins or 5 but 10. I made up a set of test leads to quickly plug onto injector, it was open circuit then dropping to 1200, 800/700 ohms which confirmed it for me. injector changed and its been fine since and runs well. The bonnet washer has been sealed up twice - bonnet to washer {both sides of} and washer pipes to washer, as it was leaking rainwater and washer fluid onto injector 4 area.
Thanks for your help....
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