Over pressure on fuel blow off pipes
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One question per topic.
No Gearbox questions
Diesel engine related problems
Think: Diesel engine, diesel fuel system, diesel injectors and glow plugs
One question per topic.
No Gearbox questions
Diesel engine related problems
Think: Diesel engine, diesel fuel system, diesel injectors and glow plugs
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- Posts: 6
- Joined: Sat Jul 10, 2021 10:29 am
- Model: C3 2006-2009, Facelift model
- Year: 2007 (07)
- Engine Size: 1.4 (8v)
- Fuel Type: Diesel
- Mileage: 90000
- Gearbox: Manual 5 speed
- DPF: No
- LHD or RHD: RHD (UK)
- Engine name: DV4 diesel (70 PS)
- Been thanked: 1 time
Hi all, help needed please and thanks for looking. Noticed a diesel pool under car & after taking off air box noticed fuel around injectors. Changed the blow off pipes as one had a little tear and also did injector test which seemed ok. So I now have no leak, but upon start up the blow off pipe that fits to injector on battery side of car almost doubles in size & then blows off, obviously got some over pressure going off somewhere? Anyone out there had same sort of problem, Don't really know where to start from here, any help much appreciated, thank you..
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- Posts: 3308
- 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
- Gearbox: Manual 5 speed
- DPF: No
- LHD or RHD: RHD (UK)
- Engine name: DV4 16-valve diesel (90 PS)
- Has thanked: 259 times
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Hello StevieStevie wrote: ↑Sat Jul 10, 2021 10:50 am Hi all, help needed please and thanks for looking. Noticed a diesel pool under car & after taking off air box noticed fuel around injectors. Changed the blow off pipes as one had a little tear and also did injector test which seemed ok. So I now have no leak, but upon start up the blow off pipe that fits to injector on battery side of car almost doubles in size & then blows off, obviously got some over pressure going off somewhere? Anyone out there had same sort of problem, Don't really know where to start from here, any help much appreciated, thank you..
Typically the blowing off of the leakoff connectors are due to worn out injectors.
How did you do the injector test?
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-
- Posts: 6
- Joined: Sat Jul 10, 2021 10:29 am
- Model: C3 2006-2009, Facelift model
- Year: 2007 (07)
- Engine Size: 1.4 (8v)
- Fuel Type: Diesel
- Mileage: 90000
- Gearbox: Manual 5 speed
- DPF: No
- LHD or RHD: RHD (UK)
- Engine name: DV4 diesel (70 PS)
- Been thanked: 1 time
Thanks for the quick reply, did the test with injector kit, not a DIY one. All seemed pretty close to one another.
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- Posts: 3308
- 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
- Gearbox: Manual 5 speed
- DPF: No
- LHD or RHD: RHD (UK)
- Engine name: DV4 16-valve diesel (90 PS)
- Has thanked: 259 times
- Been thanked: 112 times
Yes, they all do look similar. Not the usual one that towers above the others.
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 

-
- Posts: 6
- Joined: Sat Jul 10, 2021 10:29 am
- Model: C3 2006-2009, Facelift model
- Year: 2007 (07)
- Engine Size: 1.4 (8v)
- Fuel Type: Diesel
- Mileage: 90000
- Gearbox: Manual 5 speed
- DPF: No
- LHD or RHD: RHD (UK)
- Engine name: DV4 diesel (70 PS)
- Been thanked: 1 time
The car drives fine, even when it was leaking fuel, plenty of power, to be fair it pulls even harder with air box off, so this doesn't draw me to a bad injector. Would a failed fuel pressure regulator cause the pipe to blow off? Thanks
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- Posts: 1854
- Joined: Sat Apr 30, 2011 7:40 pm
- Model: C3 2002-2005, Original shape model
- Year: 2003 (03)
- Engine Size: 1.4 i
- Fuel Type: Petrol
- Mileage: 79984
- Gearbox: Manual 5 speed
- DPF: No
- LHD or RHD: RHD (UK)
- Engine name: TU3 (75 PS)
- Has thanked: 85 times
- Been thanked: 65 times
Is there a pressure difference in the fuel tank? Can you remove the fuel filler cap and listen for a sound. Also does the leakoff pipe still blow off after or with the fuel filler cap removed?
Your leakoff test shows either 4 bad injectors or 4 good ones. There isn't one that stands out as bad.
Did you time the test and measure the RPM so we could work out if the leakoff is excessive or to be expected?
You should get fault codes stored if the fuel pressure regulation isn't working correctly, are there any codes stored?
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- Posts: 6
- Joined: Sat Jul 10, 2021 10:29 am
- Model: C3 2006-2009, Facelift model
- Year: 2007 (07)
- Engine Size: 1.4 (8v)
- Fuel Type: Diesel
- Mileage: 90000
- Gearbox: Manual 5 speed
- DPF: No
- LHD or RHD: RHD (UK)
- Engine name: DV4 diesel (70 PS)
- Been thanked: 1 time
Hi c3drive, yesterday i did take filler cap off while running & made no difference or sound, no hiss of pressure when unscrewed either. I didn't time the pressure test, just did it on idle for couple minutes. However, it's thrown a couple of codes up today, Po238 boost sensor circuit high & Po203 injection circuit open cylinder 3. Very much doubt all four injectors gone at same time & it's not lost any power & actually runs fine. Very strange it runs fine while leaking, but stem the leak & seems to build to much pressure somewhere. Thanks
-
- Posts: 1854
- Joined: Sat Apr 30, 2011 7:40 pm
- Model: C3 2002-2005, Original shape model
- Year: 2003 (03)
- Engine Size: 1.4 i
- Fuel Type: Petrol
- Mileage: 79984
- Gearbox: Manual 5 speed
- DPF: No
- LHD or RHD: RHD (UK)
- Engine name: TU3 (75 PS)
- Has thanked: 85 times
- Been thanked: 65 times
Can you get pressure into the leak off pipe to the fuel tank and will it hold? I'm expecting it should leak away, back into the tank.
I think the leak off fuel will go through the fuel cooler and back to the tank.
If the return pipe is damaged by crush or crimp, or just blocked, the engine would run OK, the leak off pressure would build up quickly and blow a connector.
I think the leak off fuel will go through the fuel cooler and back to the tank.
If the return pipe is damaged by crush or crimp, or just blocked, the engine would run OK, the leak off pressure would build up quickly and blow a connector.
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- Posts: 6
- Joined: Sat Jul 10, 2021 10:29 am
- Model: C3 2006-2009, Facelift model
- Year: 2007 (07)
- Engine Size: 1.4 (8v)
- Fuel Type: Diesel
- Mileage: 90000
- Gearbox: Manual 5 speed
- DPF: No
- LHD or RHD: RHD (UK)
- Engine name: DV4 diesel (70 PS)
- Been thanked: 1 time
Thanks buddy, will have a look at this tomorrow, wanted an easy day, not pissing about with that again.. A mate said there's a game on tomorrow or something??
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- Posts: 6
- Joined: Sat Jul 10, 2021 10:29 am
- Model: C3 2006-2009, Facelift model
- Year: 2007 (07)
- Engine Size: 1.4 (8v)
- Fuel Type: Diesel
- Mileage: 90000
- Gearbox: Manual 5 speed
- DPF: No
- LHD or RHD: RHD (UK)
- Engine name: DV4 diesel (70 PS)
- Been thanked: 1 time
Update on problem. It's the little black non return valve that's given me the grief, seized up a little, very hard to push open. Was obviously putting pressure on fuel harness which led to my leaks. Done my head in, but grateful it's a couple of quid part and not an injector or other expensive bit. Hope this may help someone in the future. Thanks for the replies, no doubt I'll be back soon, it's a Citroen....
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