sharran 1998 1.9tdi engine code AFNvehicle has been to vw agents for lack of power,they have replaced injector pump and air mass sensor and also looks like egr valve,to no avail. When vehicle is driven there is absolutely no boost at all,totaly flat. i had it in today, checked cleaned and refitted egr valve (ok) checked turbo wastegate operation with vac gauge (ok) stripped and checked valve and pump timing (ok) removed turbo pipes from intercooler and checked boost pressure (by hand) plenty of boost pressure (or at least enough to feel it boost). boost pressure controll valve resistance and operation is fine. now one thing this vehicle does dowhich i think could be related is when the engine is started with no throttle the revs instantly go up to 2500rpm for 2 or 3 seconds and then back to good idle??? i have 4.1volts at the maf when reved stationary,good 5v and 12v and good earth at plug. only dtc that is flagged and does reappear is (01237 p0004) fuel cut-off valve-N109 malfunction. i believe this to just control fueling on the overun??? could i have an ecu related fault causing this poor power. list of snapshots taken. heelllllllpp. would like to sus this one out.
IDLE
INTAKE AIR MASS DESIRED 285MG/H
INTAKE ACTUAL 300MG/H
EGR DUTY CYCLE 58%
IDLE
INTAKE AIR MASS 300MG/H
AT PRESS 1020MBAR
INTAKE MAN PRESSURE 1020MBAR
2000RPM WOT
INTAKE AIR MASS 875MG/H
AT PRESS 1020
INTAKE MAN PRESSURE 1744MBAR
3000RPM WOT
INTAKE MASS 875
AT PRESS 1020
INTAKE MAN PRESS 1958MBAR
ACC POSITION 100%
3000RPM WOT
INTAKE AIR MASS DESIRED 850
ACTUAL INTAKE AIR MASS 920MG/H
EGR DUTY CYCLE 4%
SORRY FOR LONG POST BUT HOPE SOME OF YOU CAN THROW ME SOME MORE IDEAS
many thanks
sean