no power to fuel pump or inertia switch

50mustangs · #1 03-26-2011, 06:19 AM

I have a 1997 Ford Ranger xl 2wd with 3.0 liter. bought the truck with a blown engine. had three broken connecting rods. anyway, I installed a new engine and now I find that I have zero fuel pressure and I can't hear the pump when the key is turnd on. So, I checked the interia switch (GOOD). removed my bed to get to the fuel pump and found no power at the pump. went back to interia switch to check for power (I know, I should have did that before removing the bed.. live and learn..lol) (NO POWER). when I turn the key on I can hear the relays clicking but I can't hear the pump. not sure which is the fuel pump relay but all three have the same part number printed on them so I switched them (still nothing). can somebody tell me which is the fuel pump relay and where the fuse is. I have a haynes manual but it don't tell which or where the relay or the fuse is located. I checked all fuses under dash and in the power distrubution box and they are good. I found one fusible link (not sure what it went to) and it was good. how can I test the pcm? any troubleshooting tips? thank you

FireRanger · #2 03-26-2011, 06:30 AM

The computer doesn't run the fuel pump.

Underhood power distribution box....
- Top left relay is the fuel pump relay. It's probably fine.
- The 6th fuse down on the right side is the fuel system and anti-theft. I bet is blown.

50mustangs · #3 03-26-2011, 07:16 AM

nope.. all fuses are good. I read a couple forums that stated that the check engine light didn't come on when the key is turned to on position indicating the ecm is not getting power. I checked mine and the check engine light doesn't come on. maybe my pcm isn't getting power. from what I've read the pcm tells the relay when to energize the fuel pump. I followed the wire with the fusible link and I found it went to something not installed by Ford, probably a cb or some other accessery. where can I find the fusible link? thanks

87bullsnkranger · #4 03-27-2011, 12:19 AM

im sure there is a differance due to 10 years and a vulcan engine opposed to a 2.9l but not much.As far as fuseable link shouldn't be one find your wireing positive side it goes to the inertia switch then to the steering colum to ignition,ground goes up towards battery on mine the ground originally went to the silinoid on fender but has been rewired straight to battery,even a loose or faulty ground can cause your no power,all my no power to this system has been a wireing issue.

50mustangs · #5 03-27-2011, 07:58 AM

where is the PCM power Diode?

87bullsnkranger · #6 03-27-2011, 04:12 PM

if ford changed things past 93' and put the silinoid on your starter they wouldn't have moved the ground side of fuel pump anything connecting the wireing would still be on passenger inside fener,or fire wall.

FireRanger · #7 03-27-2011, 04:34 PM

Quote:

Originally Posted by 50mustangs

where is the PCM power Diode?

It's right next to the fuel pump relay in the underhood power distrobution box. Fuel pump relay is on the left. PCM diode next to it. ABS Diode in the middle. RABS resistor on the outside. Please see page 224 of your manual
http://www.fordrangerforum.com/frf/manuals/1997.pdf

50mustangs · #8 03-27-2011, 05:36 PM

FOUND IT!!!!! thanks guys the information you've provided me was very valuable and I've learned alot. two different thing were wrong. first thing was the wire at the fuel relay to the intertia switch and PCM (dark green an yellow wire) was very corroded under the distribution box. I cleaned that wire up and reinstalled. checked for power at fuel pump and I then had power. Still no noise from pump or fuel pressure. pulled pump and found wire broke. installed new pump and assembly. hit switch and heard hummmmmmm. bled air out of fuel lines. hit the starter and she fired up and purred like a kitten.

FireRanger · #9 03-27-2011, 05:48 PM

Awesome!