740 L4-2.3L SOHC VIN 88 B230F (1985)
Fuel Injector Resistor: Description and Operation
Ballast Resistor
Sent by the fuel injection ECU:
A fuel injector is designed to operate at its best with a 4 volt current. Therefore the 12V battery supply needs to drop to 4 volts before it reaches the
injectors. This voltage drop is performed by the ballast resistor (located in wiring harness on front of driver side fender in engine compartment). There is
one resistor per injector in the ballast resistor pack.
The fuel injection ECU sends a current to the system relay which controls the suppressor relay. The battery supplies the voltage for the ballast resistor
via the suppressor relay. The ballast resistor has a resistance of approx. 5.5 - 6.5ohms. This reduces the battery's 12V supply to about 4V in the injector
wiring.
