Checking return flow rate of injectors with engine running

Special tools and workshop equipment required

• Return flow meter - VAS 6684- and adapter C5

Procedure

• Remove engine cover panel ⇒ 3 Engine cover panel.
• Clean all return line connections (e.g. with standard commercially available cold cleaning solvent) before opening them.
• Dry all cleaned parts.

• Release catch -1- and pull return line connections off all injectors in -direction of arrow-.

• Fit adapter C5 from return flow meter - VAS 6684- firmly onto return line connections of all 3 injectors.
• Connect hoses of return flow meter -VAS 6684- to adapters.
• Start engine, and allow it to idle for several minutes.

• When the engine is warm and running at idling speed, the return flow rates at each of the 3 return lines must not differ by more than a small amount.

• 1) Injector units OK. Return flow rate of all injector units approximately equal.
• 2) Injector of cylinder no. 3 is not OK. The return flow rate is more than three times the lowest measured return flow rate.

• If one injector has a significantly higher return flow rate than the others (example -2-), it must be renewed ⇒ 3.3 Checking return flow rate of injectors with engine running.

Installing fuel return lines

• Carefully press connections of return lines onto injectors. You should hear them click into place. Then, carefully press the release pin downwards.
• Checking fuel system for leaks ⇒ 1.3 Filling/bleeding fuel system.
• Fit engine cover panel ⇒ 3 Engine cover panel.