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So my T5 has a lumpy idle, i just started it up and it was lumpy, no warnings on the dash etc... once driving it runs fine until you drop down to around 1k rpm or below and its lumpy again, worse from cold and still there when warm
Plugged in VCDS and did a scan and its come up with a fuel pressure regulation, error code P106500, Regulation discrepancy error
Read somewhere that if you unplug the fuel rail pressure sensor and the engine idles nicely then the sensor is faulty
So i unplugged mine and the lumpy idle disapeared but the glow plug light started flashing, plugged the ful rail pressure sensor back in and the lumpy idle came back and the glow plug light whent out
Any ideas?
Replace the fuel pressure sensor.
Yes that's what im going to try next, just trying to find online instructions on how to depressurise the fuel rail system before removing the sensor
If you can't find any, it's possible you don't need to. If it looks like a Schräder fitting, then that's probably because it is! It certainly is for the aircon pressure sensors on VAG stuff.
If you're massively worried, pull the fuel pump fuse and run it until it cuts out - standard practice for mk5 GTI HPFP followers.
online instructions on how to depressurise the fuel rail system before removing the sensor
Set up two video cameras (in case one is taken out by a flying sensor) and crack on. IANAM
online instructions on how to depressurise the fuel rail
Diesel is virtually incompressible, no stored energy. So just unscrew the sensor slowly, allowing time for what pressure there is to escape, and you will be fine :o)
The glow plug light is a general "there's something wrong" warning. There is something wrong, the sensor has been unplugged.