1991 CHEVY S-10 ECM FUSE BLOWING WHEN IGNITION IS TURNED ON

  • Tiny
  • LadyStanwyck
  • 1991 Chevrolet S-10

Electrical problem
1991 Chevy S-10 6 cyl Two Wheel Drive Manual 273, 00 miles

Hi,

A few days ago I was out driving and stopped at a business for a few minutes. I turned my S10 off while I was there. When I went to leave my S10 would not start. It would try to turn over but acted like it was not getting fuel.

Fast forward, we have changed the fuel filter, checked all of the wiring under the truck leading back to the fuel pump. We have dropped the fuel tank and pulled the fuel pump to check the connections. The fuel pump works fine if you connect jumpers to it directly. (Fuel pump was replaced approximately 2 1/2 years ago.)

After all of this it was discovered that the ECM fuse was blown. A new fuse was put it and it blew the moment the ignition was turned.

We can not find any pinched or worn spots on the wiring. Someone else has now suggested that it might be the computer brain.

Are we on the right path? I do not want to waste more time and money tracking the wrong components. Friends that are trying to help mean well but some would pull an engine to change the spark plugs if you know what I mean. : -) I do not have a lot of money and I need my truck.

Thank you for your help. Jackie

Monday, September 28th, 2009 AT 10:58 AM

11 Answers

  • Tiny
  • Docfixit
  • Expert
  • 18,991 posts

Is fuse ECM1 or ECM B?

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Monday, September 28th, 2009 AT 11:14 AM
  • Tiny
  • LadyStanwyck
  • Member

Sorry for delay. It is the ECMB fuse. Thanks, Jackie

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Monday, September 28th, 2009 AT 12:48 PM
  • Tiny
  • Docfixit
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Pull out fuel pump relay on firewall to right of brake booster the second one. See if fuse does not blow

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Monday, September 28th, 2009 AT 12:57 PM
  • Tiny
  • LadyStanwyck
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Do you mean pull the relay and then try to start the truck? I just want to make sure I am following your instructions correctly. (BTW - Thank you for responding so quickly.) Jackie

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Monday, September 28th, 2009 AT 1:11 PM
  • Tiny
  • Docfixit
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Yes pull relay and turn key see if fuse blows. Going thrugh all things off that fuse till find what is shorted

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Monday, September 28th, 2009 AT 1:15 PM
  • Tiny
  • LadyStanwyck
  • Member

Okay. I will try that shortly. Battery died due to having door left open. ≪ Big Sigh> Taking it to get it charged.

What else runs off that particular fuse? Just so I know what I am dealing with. Thanks again. Jackie

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Monday, September 28th, 2009 AT 1:20 PM
  • Tiny
  • Docfixit
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Oil pressure switch and two leads to ECM

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Monday, September 28th, 2009 AT 2:09 PM
  • Tiny
  • LadyStanwyck
  • Member

Hi, We are waiting to pick up the battery when my daughter gets back. Just curious, is it at all possible that this fuse is blowing due to a problem with the fuel pump?

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Monday, September 28th, 2009 AT 3:28 PM
  • Tiny
  • Docfixit
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That's where i" m headed your smart are you a therapist?

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Monday, September 28th, 2009 AT 3:36 PM
  • Tiny
  • LadyStanwyck
  • Member

Ha, ha, ha. Not quite. : -) I was asking because someone in this little group has been pressing that it is the computer brain, not a fuel pump issue. They are a bit upset that I refuse to buy a computer brain until we are sure that is the problem. (I do not want to spend the money on an electrical part that can not be returned if it is not needed.)

I am standing firm that nothing else will be done until we pick up the battery and test the relay as you suggested.

I really appreciate the help. Jackie

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Monday, September 28th, 2009 AT 4:06 PM

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