to test it propertly.

1st
check the voltage's. (whilst engines running and alternator's workin) voltage's at battery, ecu and fuel pump, and check there all within a safe 0.3 volts, and all over 13.0 volts.


2nd
with a fuel pressure gauge, check the fuel pressure after the reg. (do this in the ignition priming 5 seconds)


3rd
Take the tank return off the regulator, and place it in a a 5ltr can, (clean oil can or gerry can)

remove the vacum pipe off the reg, and block it.

start engine, and rev slightly (to make sure battery's chargin),

now get another 5 ltr can, and place fuel line into that one, and time for 30 seconds.

then stop engine, and measure the fuel in the 2nd can.

then do it again to make sure you get the same result within 0.1ml/min.

now refit the return and the vacum pipe.


You can now play with the regulator pressure screw, and raise it to 5 bar, and do the same as above.

Then check the data to Bosch's rated figures (i can get you these if you want )