Hi,
I have an periodic problem with limp mode after fuel rail pressure increasing. When I releaseing the gas pedal I see on my live samplings that the fuel rail pressure goes down instantly, but goes up after a second, and sometimes goes very high. When this happens it goes into limp mode.
it does not happen every time when it has one of the periods, a couple of days. It can work fine for months the it comes 3-7 days. I will attach two pictures, the blue one was without problem, no limp mode. The red one caused a limp mode problem, solved by restarting. The dip in the pictures is when I released the gas (removed the foot) and never touched the gas again. The pressure increasing, why?
what can be the problem?

 

You wont get much help here since North America didn't get any diesel engines, most high pressure related issues are due to a failing high pressure fuel pump.
Its an expensive and fiddly item to replace so i'd go thru all the other checks first like fuel rail pressure sensor and fuel filter before omitting to replace it.

 

Ok, I didn’t know you didn’t have so many diesels. Yes replacing the high pressure pump is expensive so I will look for other reasons first. The weird thing is that is coming and going. It’s away several months, that give me the impression that’s not anything mechanical.

 

I'm in Australia where they are mostly diesel, the internment nature of the fault is usually how they fail. It will gradually get worse until it goes into limp everytime you stick the boot in.