No power to fuel pump

Tiny
YJFANATIC
  • MEMBER

I am completely out of ideas on a solution for this fix. I have tried everything I know to test and diagnose my problem, and the Jeep still isn't running. Everything up to this point has led me to believe that the PCM is bad. I previously had a '94 wrangler that had this same problem. Running down the road one day and instantly lost power to fuel pump. The PCM was bad. I'm guessing that's what is wrong with this one. Any ideas would greatly be appreciated.

What I know:
1. Fuel pump is good (12V) connected to it and it runs.
2. Fuel gauge wire (tan/blk) has 7 volts on it and gauge itself is pegged full.
3. Ground is good.
4. When key is initially turned on, both the fuel pump and the ASD relay "click" and then there is an additional "click" immediately following, which I'm assuming is the ASD relay killing the power.
5. The jeep will run with the fuel pump wired directly to the battery, so I'm assuming the crankshaft sensor is good as well as any other sensor that could normally prevent the Jeep from starting or cause the ASD relay to kill power.
6. There is no check engine light on whatsoever and when I flash codes (ignition on-off, on-off, on-off), the only codes showing are 12 and 55, so not displaying any trouble codes.

I have literally tried EVERYTHING to fix this problem.
Anybody have any ideas?

Was this
answer
helpful?
Yes
No
Monday, October 29th, 2012 AT 2:42 PM
Tiny
HMAC300
  • EXPERT
  • 45,722 POSTS

A fuel pump will not set a code unless you are running lean. You need to see how much if any voltage is going to the pump. KH low sent you amessage on how to check if power is going to it. All you really need is a test light to see if you aregetting voltage or not. You need to see if the org/blk wire is gettingpwoer not the tan one. The tanoneis for fuel gauge. If you are getting power with the relay jumped you have a short in that wire someplace. If not then the pcm isn't turning the relay on or yu have a bad connection

Was this
answer
helpful?
Yes
No
Monday, October 29th, 2012 AT 7:12 PM

Please login or register to post a reply.

Other Fuel System Pump No Power Questions