Reatta V6-231 3.8L VIN C SFI (1990)
The injector balance tester is a tool used to turn the injector on for a precise amount of time, thus spraying a measured amount of fuel into the manifold.
This causes a drop in fuel rail pressure that we can record and compare between each injector. All injectors should have the same amount of pressure
drop (+/- 10.0 kPa). Any injector with a pressure drop that is 10.0 kPa (or more) greater than the average drop of the other injectors should be considered
faulty and replaced. Any injector with a pressure drop of less than 10.0 kPa from the average drop of the other injectors should be cleaned and retested.
STEP 1:
Engine "cool down" period (10.0 minutes) is necessary to avoid irregular readings due to "Hot Soak" fuel boiling.
Disconnect harness connectors at all injectors, and connect injector tester J-34730-3, or equivalent, to one injector. With ignition "OFF" connect fuel
gauge J347301 or equivalent to fuel pressure tap. Wrap a shop towel around fitting while connecting gage to avoid fuel spillage. At this point, insert
clear tubing attached to vent valve into a suitable container and bleed air from gauge and hose to insure accurate gauge operation, by applying B+ to fuel
pump test terminal. Repeat this step until all air is bled from gauge.
STEP 2:
Apply B+ to fuel pump test terminal until fuel pressure reaches its maximum, about 3.0 seconds. Record this initial pressure reading. Energize tester one
time and note pressure at its lowest point (Disregard any slight pressure increase after drop hits low point). By subtracting this second pressure reading
from the initial pressure, we have the actual amount of injector pressure drop. See NOTE below.
STEP 3:
Repeat step 2 on each injector and compare the amount of drop. Usually, good injectors will have virtually the same drop. Clean and retest any injector
that has a pressure difference of 10.0 kPa, either more or less than the average of the other injectors on the engine. Replace any injector that also fails the
retest. If the pressure drop of all injectors is within 10.0 kPa of this average, the injectors appear to be flowing properly. Reconnect them and review
DIAGNOSIS BY SYMPTOMS.
NOTE: The entire test should not be repeated more than once without running the engine to prevent flooding. (This includes any retest on faulty
injectors).