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Checking injectors with vacuum > < Testing injectors

Polo Mk5

Checking return flow rate of injectors (at starter speed)
Checking return flow rate of injectors (at starter speed)
  Note
t  Leaky regulating valves in injectors may lead to irregular engine running or may prevent engine from starting.
t  To check regulating valves for soiling (and with it higher leakage), further to the "classical" return quantity measurement, checking with vacuum is also possible.
t  Observe instructions for working on fuel system → Chapter.
»Carry out the following work sequence«
   
–  Open return line connection -3- of injectors to be tested at the fuel return pipe using a small screwdriver and long-nose pliers.
–  Collect escaping fuel with a cleaning cloth.
  N20-10829
0.5 bar fuel low-pressure system:
–  Seal open return line connection with a blanking plug -arrow-.
  N23-10478
6.0 bar fuel low-pressure system:
–  Seal open return line connection with a blanking plug -arrow-.
Continuation for all vehicles
–  Measure during engine start with starting speed ≥ 230revs/min.
l  Return flow rate specification: 0 ml
l  Droplets are allowed
l  If a flow rate can be measured, at least one injectors is faulty.
–  Check injectors with vacuum → Chapter.
  N23-10479

Checking injectors with vacuum > < Testing injectors