MY 94 RANGERS FUEL PUMP WILL NOT COME ON. NEW PUMP & FILTER. CAN CONNECT FROM BATTERY TO PUMP AND COMES ON BUT NOT WHEN YOU TURN THE IGNITION KEY. TRIED EVERYTHING I CAN THINK OF ANYONE ELSE HAVE ANY SUGGESTIONS.
Here are a few suggestions: - Check the fuel pump relay
- Low voltage in pump power supply
- ground connection
- faulty pump wiring
Also, make sure your inertia safety switch is not triggered.
You'll need a wiring diagram to help you.
If you haven't checked the fuel pump relay yet, that's where I would start.
August, 30, 2008 AT 4:59 PM
Thanks, Tried the fuel pump relay and inertia switch reset wasn't tripped. What do I do if low voltage in the fuel pump power supply?
September, 2, 2008 AT 12:50 PM
Usually, if you have a low voltage, it means there is a high resistance somewhere in the circuit.
'Somewhere' is the word here. It's impossible to tell which part is defective until you check all the components of the circuit for high resistance (wires, relay, fuse, etc).
Keep in mind that a component that 'looks' good is not necessarily working right.
DON'T check components by doing a continuity test; it will only tell you if there's current going thru the component but not if there's ENOUGH current going thru it.
You need to find what the normal resistance is for each component, and then do an Ohm test and compare what you have with what it should be.
I'll be honest, troubleshooting an electrical problem can be a pain in the butt.
I would not do this until I've rulled out any other possiblities.
If your voltage reading at the pump is normal when you turn your key to 'start', low voltage is probably not the problem.
September, 11, 2008 AT 12:28 PM
I have the same problem and have been to two ford techs. So far we think that something is keeping the PCM from completing its functions. I fill like a anti thelf module is in the circuit somewhere but even the ford tech manuals will not show it in the diagrams. Good luck. I have replaced the PCM twice. Iwill let you know if I find the problem.
November, 25, 2008 AT 9:47 PM
I have replaced fuel pump assembly, new fuel pump relay, all fueses are good. If I bypass the relay the fuel pump cycles but truck wont start but with new relay in place and turning the key nothing happens I have been told that its in the ECM im kinda lost as of what to do now this is my only vehical and im about to loose my job because of this this has become very stressful so any help would be great
December, 4, 2008 AT 8:15 AM
Problem Solved. Had a buddy who hooked it to a diagnostics computer. He was getting absolutely no readings from my ECM. So I replaced it and it fired right up and hasnt missed a beat since. Hope it helps. Thanks for all the help recieved from the forum.