1999 Ford Mustang Repair Question
Mileage: 72,580 miles.
Have no power to the ground wire of fuel injectors
Asked by morris1299Answer
Possible the injector ground driver/s of the computer or wiring problem
If you use a normal test light to test the injector pulsing, you are not going to get anything.
You need a noid light to detect the pulses.
So how do I test the ground driver of the computer, do i just follow the steps of disconnecting all the injector plugs and single test one by one until i loose signal to pin point the faulty injector, if so what does this have to do with the driver and how do i test the driver itself. Also whats the difference in a noid light and normal test light, and is it easy to find a noid light???
You can get the noid light from parts stores. Normal test lamp requies a high voltage to light and the pulsing of the injector circut is too fast for the test light to be able to show.
When engine is running, the computer wuld ground the injector circuit to operatethe injectors. Do you have battery voltage to the injector wire harness?
when you say battery voltage to the harness are you refering to voltage when the ignition switch is on not crancking if so than i do have battery voltage to the harness.
would it be perferable that i should use a volt meter instead when conducting the fuel injector test.
Use the noid lite on the injector harness if it doesn't flash its either no powwer to it or the computer is not driving it or wiring problem
I ran another test today i located a noid lite and conducted a test and this was my outcome. I first started with one injector it has constant power with ignition switch on (no cranking) i reversed polarity to test pulse power and initially found no pulse when cranking, i disconnected all injector wire harness and still got no pulse power during the cranking process. when ignition is in the on position and your just about to full turn key to crank engine it has a quick may quarter of a second power to pulse side, than as you continue to crank engine all power is like cut off. I had also connected a OBDII diagnostic reader and it pulled a code (fuel rail pressure sensor high output)i think if i rember correctly code was (P0194). after attempting these procedures i plugged back injectors and tried cranking engine again and it wanted to start(it almost started) but just couldnt get it to run. Please help me as to where will turn to next in checking or to diagnose, im getting lost here it seems at times.
sorry i got that trouble code wrong and data it said (P0193 – Fuel Rail Pressure Sensor Circuit High Input) is this sensor located directly on top of the fuel rail (driver side) and what does this normally mean that this sensor needs replacing. also there were no other codes listed only this one.
P0193 can be due to disconnected fuel pressure sensor hose. It can also be caused by excessive cranking without engine starting so we should not worry about this as it is the injectors that are not working.
Lets try this.
With test light connected to injector RED wire.
Turn ignition on.
Test light should come on.
Crank engine.
Test light shoudl remain on. If not, you have a ower supply interruption and it could be a faulty ignition switch.
Disconnect injector wireharness.
Attach noid light across the two terminals.
While cranking engine, the noid light should flash, if not, the PCM is not grounding the circuit.