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Ron, ASE Certified Technician
Category: Ford
Satisfied Customers: 33023
Experience:  23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs
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Ford F150 Pickup 4x4 no fuel injector pulse 1990 f150 5.0

Resolved Question:

no fuel injector pulse 1990 f150 5.0 automatic
Submitted: 5 years ago.
Category: Ford
Expert:  Ron replied 5 years ago.
Hello and Welcome to Justanswer,

My name is XXXXX XXXXX I am here to try and assist your with your question.

Do you have key on 12 volts on the red wire at the injector connectors?
Customer: replied 5 years ago.
Expert:  Ron replied 5 years ago.
The power to the injectors come from the EEC relay , go to the EEC relay and see if the red/green wire and the yellow wire are both hot with the key in the run position>.

Te EEC relay is on the LH Side Of Engine Compartment, On Relay Bracket (brown one)
Customer: replied 5 years ago.
Expert:  Ron replied 5 years ago.

Yes what?


If the red wire out of the relay is hot and not at the injectors, then you have an open circuit from the relay to the injectors in the harness some place.

Customer: replied 5 years ago.
there are two relays side by side what does the other relay operate ?it has a large yellow wire and 3 small wires
Expert:  Ron replied 5 years ago.
The brown one is the EEC relay and the other one is the fuel pump relay.
Customer: replied 5 years ago.
any suggestions as to where to look for the open circuit left side or possibly a fussable link on the right side near the battery?
Expert:  Ron replied 5 years ago.
If the red wire coming out of the EEC relay is hot , the fuse links are fine, the relay get power on the yellow wire from the fuse links. I would take a look at the harness from the relay to the injector and over to the PCM as the red wire supplies power to both. In most cases it just easier to overlay a new wire. The red wire splices togater at the Rear of the LR fender apron.
Customer: replied 5 years ago.
i the pcm has power to it .with snap-on modis scan tool , i can check koeo circuit. run a wire from theeec relay to one of the injector's red wire?
Expert:  Ron replied 5 years ago.
Yea eaither that or open the harness up on teh LH rear side and fine the splice S121 and add it there. Try it to the injectors first , this should get you your pluse .
Customer: replied 5 years ago.
Expert:  Ron replied 5 years ago.
That makes my day when I hear this, great job and it was my pleasure for sure. Your very welcome and thank you very much as well.
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