2000 b4 runs 1 bar on primary but only .7 on twin mode ? thoughts

[lachlan]

first step was check codes

got

21 vehicle speed sensor

22 knock sensor

65 differential pressure sensor

reset ecu , test drive 22 comes back

fix knock sensor plug . re test drive , 1 bar primary . .7 bar on twin . very consistent . runs fine other wise . is it possible the differential pressure sensor is backwards ?

seems odd as it has turbo back exhaust from both turbos .

i see the ecu will go to a standard fuel map and pull 5 degrees timing if the knock sensor is mia

any other thoughts ?

[Rosssub]

Secondary relief valve not sealing properly? The Differential pressure sensor should be marked/labelled 21/22 each side.

[lachlan]

good point

yeah surely it would have a spaz if the ecu saw boost from the 2nd turbo first . didnt look that closely .

was odd as it had no intercooler bracket on primary side and there was nothing holding the pipes to the diff pressure sensor

so i think jonny 20det and tama have been in there at some stage

might inspect 2ndary relief valve . as both bovs split the diaphragm on my bg5a.