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Check the open nozzle units > < Checking return flow rate of injectors with engine running

Leon Mk2

Checking return flow rate of injectors at starter cranking speed
Checking return flow rate of injectors at starter cranking speed
  Note
If the engine cannot be started, the return flow rate of the injectors can also be checked using the starter cranking speed.
Consult the equivalence table for tools and equipment according to applicability among Seat / VW / Audi / Skoda → Chapter.
Special tools and workshop equipment required
   
t  Injection rate tester -V.A.G 1348/2 B-, see equivalent → Anchor
t  4 hoses to fit return line connections on injectors (made up in the workshop).
Operation process
  Caution
Risk of malfunctions caused by dirt.
Observe → Chapter „Rules for cleanliness and instructions for working on fuel system“.
Each injector normally has a relatively low return flow rate. If the return flow rate at one injector is relatively high compared to the other injectors, that injector is probably defective.
  W00-0614
–  Remove engine cover panel -arrows-.
–  Clean all return line connections (e.g. with commercial cleaning solution etc.) before removing.
–  Dry all components after cleaning.
  E10-10127
–  Pull return line connections off injectors; to do so, press tabs -1- and -2- down and at the same time pull release pin upwards -arrow-.
  Note
Pay attention to absolute cleanliness. No dirt may get into the extracted injector return lines or the injector connections.
  A23-10455
–  Unplug electrical connector -arrow- at fuel pressure regulating valve -N276-.
  Note
This prevents fuel from being injected when starter is operated.
–  Connect the 4 hoses to the return line connections of the 4 injectors.
–  Run the 4 hoses into injection rate comparison meter -V.A.G 1348/2 B-.
–  Operate starter 3 times. (wait approx. 20 seconds between each start attempt in order to prevent the starter from overheating.)
t  Specification of return flow rate: 0 ml
–  If fuel comes out of one injector, that injector must be renewed.
–  Again connect the plug of the control valve for fuel pressure -N276-.
Installing fuel return lines
–  Push the return line connections carefully over the new seals and onto the injectors. The catch should engage audibly. Then press release pin down carefully.
–  Check fuel system for leaks → Chapter.
–  Erase fault in fault memory using diagnostic tester.
  A23-10406

Check the open nozzle units > < Checking return flow rate of injectors with engine running