Fault Code Woes - P1065 - Fuel Pressure Regulation Discrepancy

[Trenchman]

Hi All, 

I have more 2009 CR TDI 170 4WD woes, so hoping to pick some brains. 

Original woe turned out to be a buggered high-pressure fuel pump. Pump replaced but then my baby began to fuel weirdly once at motorway cruising speed. Ignition warning light flashes and into limp mode. Turn off/on engine. Light disappears then repeat. Eventually engine warning light comes on.

Mechanic checked it as fault code P1065 -  Fuel Pressure Discrepancy. 

 

I've been told it could be... 

* Newly fitted fuel pump not set up properly. 

* EGR Valve

* Fuel Pump Regulator and/or filter

* Knackered injectors

 

Any/all ideas welcome! 

 

Thanks

Trenchman

 

Edited 31 January, 2023 by Trenchman
Spelling mistake

[Derbyshirebod]

With it being common rail I don't believe the setting of the fuel pump is that critical and it's not difficult to set them correctly. I've had to do it when I changed the cam belt on my Superb.

 

When these type of high pressure pumps fail quite often it's the bearings start to break up and bits of metal get pumped into the fuel rail and damage the injectors.

 

The only way you will find out if the fuel injectors are okay is to remove them and have them bench tested at a diesel injector specialist.  Expect to pay around £25 to have each injector tested. I paid £840 for 4 remanufactured exchange injectors for my 2012 CR170 4x4  Superb.

 

A new fuel pressure regulator is around £25 and easy enough to change , 

 

 

Edited 31 January, 2023 by Derbyshirebod

[Trenchman]

Thanks for this. I read your thread on this (most helpful) but the thought of knackered injectors is terrifying! Up to a grand + that I haven't got for test and replace! Eeek! 😁 

[Derbyshirebod]

9 hours ago, Trenchman said:

Thanks for this. I read your thread on this (most helpful) but the thought of knackered injectors is terrifying! Up to a grand + that I haven't got for test and replace! Eeek! 😁 

 

If you had an EGR issue I would have thought when they scanned the car you'd have also had an EGR fault related fault code.

 

Changing the fuel filter is relatively inexpensive and it just might resolve your problem. Even if it doesn't,  it gives you the opportunity so see if there is any metal particles in the filter bowl. You said that you've had the pump replaced already and that might have pumped debris round your fuel system ? There isn't going to  be much point in replacing any more expensive parts of the fuel system until any debris if any has been removed. Which is the 1st thing I did after I bought my Superb with a low fuel rail pressure issue.

 

I also bought a new fuel pump pressure regulator which cost £25. Again still got low fuel rail pressure error code.  By this time the car had gone from going into limp mode every now and again to every day! 

 

I then removed the injectors and got them tested as they were easier and quicker to remove than the fuel pump. It cost me £100 to get told they were all leaking badly. Not cheap buying remanufactured injectors  but cheaper than new injectors I decided in the long run it was likely to more cost effective solution. On replacing the injectors when I came to clean the injector seats I could see they had all been re-cut rather badly ! So this wasn't the 1st set of replacement injectors my car had had! Okay the car had done 180,000 miles. 

 

I guess you could try your luck with 2nd hand injectors ? Though I personally think it's likely to be a false economy, from what I've read this type of injector used in these engines are prone to failing.

 

Had I know the price of new injectors at the time I would have tried to get the seller to lower his price even further or even walked away !  Though even after repairing it I still think I got a cheap car at just under £2500 all in. 

Edited 1 February, 2023 by Derbyshirebod

[Trenchman]

Thanks for the tips. 

Very much appreciated. Hopefully might give the mechanic a steer!