Volkswagen Workshop Service and Repair Manuals

Checking injectors with vacuum   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. Special tools and workshop equipment required

t  Hand vacuum pump -VAS 6213-

t  Make an -adapter- from a return line. »Carry out the following work sequence« –  Collect escaping fuel with a cleaning cloth. –  Open return line connection of injector to be tested using a small screwdriver and long-nose pliers.

Always renew clips.

–  Pull off return line in direction of arrow.   WARNING t  The fuel and the fuel lines in the fuel system can become very hot (danger of scalding)! t  The fuel system is also under pressure! Before opening the system, place cloths around the connections. Then carefully loosen connection to release the pressure! t  Wear eye and hand protection when performing any type of repair work on the fuel system!

–  Undo fuel high-pressure line -2-. To do this, only undo union nuts on high-pressure accumulator -1-. –  Connect adapter to injector to be tested.

–  Use hand-operated vacuum pump -VAS 6213- to generate vacuum of approx. -500 mbar. If injector is OK, pressure remains constant for 30 s. If injectors are defective, the pressure drops within 2 ... 3 s to 0 bar –  Renew injectors → Chapter.