1995 5.8
#1
03-16-2016, 07:20 PM
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1995 5.8
I recently went and got a new motor for a 1995 f150. Got everything plugged in and connected. I turned it over to find that my injectors are not firing. I am getting the right amount of fuel . my problem is my harness that contains the injectors are only getting 0.14 volts whereas the rest of the vehicle is getting 12.0 volts as it should. I have changed my ecu, PCM, and the same problem still exist.... Please help
#2
03-16-2016, 07:24 PM
#4
03-16-2016, 08:48 PM
This may be getting a bit beyond me especially from a distance you understand. But things like the TPS run at 5 volts or thereabouts. Most of the computer controlled things like sensors etc. run at low voltage.
So best I can do to help you with that part is if you can figure out which pin (colour coded wires) runs the TPS, it should be showing 4.5 to 5 volts - that's the amount of voltage that goes TO the TPS, then the resistor in the TPS sends a signal back to the PCM which varies between .9 and 4.5 to 5 volts, depending on the throttle position.
The point is, don't expect to see 12 volts to any of the computer related things on the motor - lower voltage is to be expected.
I mentioned the TPS in the first post because there are 2 positions that eliminate the injectors - foot to the floor while cranking (to clear a flooded motor just like in the carburetor days - they designed it that way) and a signal below I believe it's about .8.
So that's a possibility for your no injector pulse problem.
The other situation is that (I believe) if the PCM doesn't detect a signal from the PIP in the distributor (however the signal gets routed) that tells it that the motor is turning, it won't send a signal to the injectors telling them to open - a fail safe also designed in.
I just mention those 2 things because either of them could cause your injectors to not be opening. There could be other causes, but those are a couple you could be looking at.
So best I can do to help you with that part is if you can figure out which pin (colour coded wires) runs the TPS, it should be showing 4.5 to 5 volts - that's the amount of voltage that goes TO the TPS, then the resistor in the TPS sends a signal back to the PCM which varies between .9 and 4.5 to 5 volts, depending on the throttle position.
The point is, don't expect to see 12 volts to any of the computer related things on the motor - lower voltage is to be expected.
I mentioned the TPS in the first post because there are 2 positions that eliminate the injectors - foot to the floor while cranking (to clear a flooded motor just like in the carburetor days - they designed it that way) and a signal below I believe it's about .8.
So that's a possibility for your no injector pulse problem.
The other situation is that (I believe) if the PCM doesn't detect a signal from the PIP in the distributor (however the signal gets routed) that tells it that the motor is turning, it won't send a signal to the injectors telling them to open - a fail safe also designed in.
I just mention those 2 things because either of them could cause your injectors to not be opening. There could be other causes, but those are a couple you could be looking at.