90S10NoFuel

Hello,
Have a 1990 S10 2WD 4.3 that is not getting fuel out of the injectors. Fuel pump has been replaced and is working. Getting fuel to the throttle body but nothing out of the injectors. Have changed out the relays on left side of firewall in engine bay. Have replaced the ignition switch. Have swapped in a known "good" PCM. Have checked all fuses. Any suggestions would be appreciated.

old_master

With the ignition switch in the RUN position, do the red and the white wires at the injectors both show battery voltage?

Do the dark green and the dark blue wires both pulse a negative signal when cranking?

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90S10NoFuel

When I tried to check voltage, I was checking across the pair of wires at each injector. Guessing that was the wrong way to go about this based on what you asked. I should be checking from each individual wire to ground then? Was not showing any voltage when I would try to read across the wires of each connector.

ctwright

Not sure how your vehicle is wired, but ones I have worked on each injector already has 12 volts on one of the wires going to them with the power on. They get their ground signal pulses from the computer. Put the key in the on position, and take a test light, put the clip to a ground on the vehicle and other end to each wire going into your injectors, one should light up. If it does that means that the injectors aren't getting the ground pulses from the ecm. If it doesn't light on either side that means you probably have a blown fuse some where. Make sure I am right though, your vehicle may be different it may have one wire going to each injector is supposed to be a ground and the other gets a positive pulse from the ecm instead, I haven't seen any like that but I'm not sure either. You can get a Haynes manual and look in the wiring diagrams you should be able to figure this out, look in the diagram that says engine control wiring diagram. You should also be able to figure out which color wires are supposed to be what and be able to trace it down and find the problem.

ctwright

Sry old master I wasn't trying to repost what you already told him, there wasn't any replies yet when I started typing I guess I'm a slow typer.

old_master

ctwright is correct, the injectors are supplied battery voltage from the ECM1 fuse, (10amp) when the ignition is in the RUN and START positions. The ECM receives a pulse signal from the ignition module and then the ECM supplies a pulse ground to fire the injectors while cranking and running.

__________________
The global warming agenda has never been about science or health or human life. The global warming agenda is about stripping us of our freedom and redistributing our wealth. The only things truly endangered are our rights.