Onidlanor77
New Member
Hi I have vw transporter t6 cxfa engine 2017 when I bought van I did renew whole fuel system including pipes ,injectors new hpfp adter rebuild,in tank pump aftermarket and genuine rail with regulator and pressure sensor as one peace.Van drives fine but under hard acceleration, not always is going to limp mode with p0087 fault. After testing low pressure side it is obvious why i have around 3 bar when engine idling. Did all test according vw test procedures and it look like pump is ok so what i did last time was restricting return flow directly from hpfp to tank and I so perfect 4.5 bar steady pressure while engine was running so is it possible to test somehow check valve in hpfp which is opening to return unused diesel back to tank?I am thinking about blocking hpfp pipe to rail and just run pump from tank on its own but I am not sure if it is going to be valid test without running engine 