Had problem recently with my jeep dying if I let it try and idle without keeping over 1200rpm or when driving and trying to accelerate too much(ie- 1//4 mile to get to 25mph). Was going to replace the pump after getting a fuel pressure test that barely moved the needle but on a whim I decided to check the voltage going to the pump. When first turned on one wire spikes to around 12v and goes off, the middle wire goes to about 6.5 and holds steady at that, the third is the ground I'm assuming. The volts do not change whether I use the third wire or ground the volt tester to the frame. Are these normal or what? The ballist resistor tests at 1.5ohm(normal from what I heard) and have replaced the relay without any luck. Any ideas what it may be?

 

The fuel pump is only energized for 2-3 seconds at key on.

The lower voltage your reading is the fuel level sensor, basically a rheostat.

 

So I guess it would be good to just replace the pump like I planned and see it thats my problem?