1999 Ford Explorer 99 explorer fuel relay voltage drop

1999 FORD EXPLORER
16,600 MILES • 6 CYL • AWD • AUTOMATIC
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JCFOSHE
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  • 2 POSTS
I have a 99 explorer that I purchased. They said the timing has jumped, so before pulling the motor I have changed the spark plug, fuel filter. It will hit and run a little off starting fluid. So I started looking at the fuel system. I noticed that the voltage going to the inertia switch is only 6.70 volts. I get the same volts at the fuel pump. I changed the relay and still get the same volts. I can jumper the power across and get 12volts and the pump runs. Why am I losing 5.3 volts through the relay?
Jul 3, 2010 at 4:34 AM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,240 POSTS
Have you checked for bad or corroded connections? Bad grounds can cause this too as well as a partially broken wire.

Let me know.
Jul 4, 2010 at 5:56 AM
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JCFOSHE
  • MEMBER
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Why could it be a bad ground or broken wire when I can jump the hot over to the the post when I have removed the relay and can get 12 volts? It only drops when the relay is in place. Also the repair manual states when I turn the key on one post on that relay should have 12 volts for a few seconds then drop but mine stays on constant. Can I be having a pcm issue?
Jul 4, 2010 at 7:54 AM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,240 POSTS
It could be the PCM. However, I feel that there is a wiring issue that is cutting power. As far as the ground issue, if it works properly when you run a jumper directly, then the ground isn't an issue.
Jul 4, 2010 at 3:02 PM
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