Number 30 fuse keeps blowing

Tiny
LUIS RAMIREZ
  • MEMBER
  • 2001 FORD F-150
  • 5.4L
  • V8
  • 2WD
  • AUTOMATIC
  • 128,900 MILES
My truck cut out on me. Replaced fuel pump and started I didn’t drive it for a few days. I started the truck a few times for about 16 minutes it was fine but when I started to drive it wouldn’t go farther than a block and it keeps blowing the number 30 fuse under dashboard and when a soon as I turn the key it shorts out again. After I bring it to my drive way everything is fine it only blows it a few minutes after I drive it. Please help. Thank you
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Tuesday, September 15th, 2020 AT 9:38 AM

9 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi,

The fuse you mentioned has nothing to do with the fuel pump. Did this just happen since the pump was replaced? Also, I need to confirm something. Does the fuse blow as soon as you turn the key on or can you still drive a block?

Was there anything other done that included working with the electrical system before this started?

I attached two pics below. Please confirm that I have the right fuse that you are having trouble with.

Let me know.
Joe
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Tuesday, September 15th, 2020 AT 5:30 PM
Tiny
KASEKENNY1
  • EXPERT
I attached the list of things that this fuse controls. The way to figure this out is to unplug these things one at a time and drive the vehicle until the fuse no longer pops. Clearly there are other ways like tracing wiring or testing coils with oscilloscopes but most people don't have the time and tools to do this. Because of this it is best to get a bunch of 30 amp fuses and unhook each item one at a time until you find it.

Based on what it is doing, I suspect you have a failing coil as it is pretty common for a failing/shorted coil to pop a fuse because the secondary side is shorted to the primary side. The primary side of the coil is low voltage and the secondary is high voltage. When it is shorted it overloads the circuit and pops the fuse.

So you should have what are called coil on plugs on this engine so you just need to locate each coil and unplug them one at a time. There is no issue with running on 7 cylinders for a short time just to test this out. So I would bring the fuses with you and once it pops, unplug the next coil and plug that one back in while you are on the test drive rather then coming all the way back on 7 cylinders or at least plug that one back in once it pops and then drive back. Basically, just limit the amount of time with it unplugged. This will avoid driving any further then you need to and speed this process up a little bit.

Let me know if you have questions. Thanks
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Tuesday, September 15th, 2020 AT 5:38 PM
Tiny
LUIS RAMIREZ
  • MEMBER
Thank you Kasekenny1, I ll let you know the results.
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Wednesday, September 16th, 2020 AT 1:26 PM
Tiny
LUIS RAMIREZ
  • MEMBER
Hi Joe. Yes, you're right it has nothing to do with the gas pump and to confirm looks like it blows up the fuse only after 2nd or 3rd gear and it would only blow it and then put a new fuse and would drive back home. But now after it blows it and put a new fuse it blows it as soon as I turn the key I can hear and see when it shorts out. And the reason I replaced the fuel pump is because it cut off on me while driving a about 2nd gear and a mechanic told me it was the gas pump. I put a new pump and continue not starting. So I checked the fuse box inside cab and found a number 30 was short replaced and started right away but when drove off about a block from my house cut off again. Thank you for your help.
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Wednesday, September 16th, 2020 AT 1:35 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi,

What you will need to try is exactly what KaseKenny suggested. If you remove one fuse at a time until you find the one which allows the fuse to not blow, then we will know what circuit we are dealing with.

Joe
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Wednesday, September 16th, 2020 AT 6:17 PM
Tiny
LUIS RAMIREZ
  • MEMBER
Thank you guys, but looks like it was a wire that was touching the shock absorber by the battery and by the air conditioner where to add Freon to the system are a lot of wires and one of those was the problem.
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Wednesday, September 16th, 2020 AT 7:28 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi,

I'm glad to hear you found it. Electrical problems can be difficult. Regardless, please feel free to come back anytime in the future if you need help or have questions.

Take care,
Joe
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Wednesday, September 16th, 2020 AT 7:31 PM
Tiny
LUIS RAMIREZ
  • MEMBER
  • 2001 FORD F-150
  • 5.4L
  • V8
  • 2WD
  • AUTOMATIC
  • 128,000 MILES
Hi Joe, you answered a question about my truck. Yes, now I have the truck jacked on towers and as soon as I turn the key it shorts out and nothing else has been done except replaced the fuel pump. Thank you so much for your help.
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Thursday, September 17th, 2020 AT 1:40 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
Okay, I need you to recheck the wiring at the fuel pump. When you first turn the key to the on position, the fuel pump primes for a couple seconds. I suspect the power supply to the pump is shorted. Here is what I suggest.

Do this and let me know the results.

1) Remove the fuel pump relay from the fuse box under the hood. (See attached pic)

2) Replace the fuse.

3) With the relay removed, turn on the key and see if the fuse blows.

Let me know.

Joe
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Thursday, September 17th, 2020 AT 1:40 PM (Merged)

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