Well, I have my first problem that I am hoping the forum can assist me with.
I have recently taken ownership of a 2012 build MY13 TDI with 138000 kms. I have only done around 500kms in it so far but have experienced an issue twice where the return fuel line from the injectors has blown off at the pressure retention valve.
Both times this occurred in similar circumstances.
- Had been driving the car for about an hour
- Accelerated reasonably hard and suffered a loss of power wth some shuddering
- No error codes were generated or warning lights came on
In both cases the same hose had blown off and fuel has leaked all over the engine and down into the V of the engine. ( the first time it happened, I was able to suck out over 2 litres of diesel from the v between the two cylinder banks)
In both cases, refitting the hose, allowed the engine to run properly again. If I drive the car 'sedately' then the problem has not re-occurred.
I have tried searching for similar problems with minimal success. I did find this thread
in another forum where the OP confirmed that a part in the fuel pump was replaced which fixed the issue (Possibly the Fuel Metering Valve ???)
One thing that makes me think the issue may have been there for the previous owner is that the 2 inlet hoses and the 1 outlet hose on the pressure regulation valve plus one hose connection on the right bank of cylinders (when standing at the front) have steel hose clamps fitted. All the other hose connections on the turn lines at the injectors are just hoses pushed onto the barbed plastic fitting. I have attached pictures (I hope)
I have read in VW SSP 820133 that the pressure retention valve generates a back pressure of between 3.5 and 10 bar to the injectors.
I am obviously getting too much pressure in these lines and it is causing the hose to blow off (even with a hose clamp).
So the question is, what could be causing the excessive pressure?
My thoughts are:
- faulty pressure retention valve restricting the flow and causing higher than normal back pressure
- one (or more) injectors having too much flow into the return line which then causes a higher than normal pressure drop through the pressure retention valve and results in too much pressure
- A restriction somewhere else in the fuel return line after the pressure retention valve. The hose out of the pressure retention valve runs to a banjo fitting on the injector rail where it tees in with the outlet of the Fuel pressure regulator valve N276 and then back to the fuel filter housing at the left rear.
- Pressure regulator valve N76 dumping high flow into return line causing higher than normal back pressure.
- Problem with something in the fuel pump as per the linked post above? There doesn't seem to be a direct connection between the pump and the return line so unsure how this could cause it.
But how do I determine which one it is?
I do have an OBDeleven (like VCDS) - Is there something I can measure?
Do others have any hose clamps on their return line hoses?
Has anyone experienced this or heard of it happening? Any links to threads?
Thanks in advance