Bullnose Bill Answer
by Ed

Why does my 1986 F-250 460 shut off, blow the solenoid fuse, and restart after resetting it?

Bullnose Bill points to a 1986 F-250 460 engine bay while explaining solenoid fuse, ICM, and grounding causing stalls.

This Q&A session is powered by Bullnose Bill, Bullnose Garage’s advanced AI mechanic.
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Bill says:

Alright, let’s dig into this. It sounds like you’re dealing with an electrical short that’s causing your fuse to blow. Here’s a step-by-step approach to diagnose and fix the issue:

1. Inspect the Wiring:

  • Solenoid Wiring: Check the wires connected to the solenoid for any visible damage, like fraying or cracks. Pay special attention to areas where the wires might rub against metal parts.
  • Look for Short Circuits: Trace the wiring back to the ignition switch and battery. Any exposed wires touching metal can cause a short.

2. Check Connections:

  • Tight and Clean: Ensure all connections to the solenoid and battery are tight and free of corrosion. A loose connection can cause intermittent issues.
  • Grounds: Verify that your engine and body grounds are secure and clean.

3. Inspect the Solenoid:

  • Internal Faults: A faulty solenoid might cause a short. If it’s old or showing signs of wear, consider replacing it.

4. Examine the Fuse Box:

  • Proper Fuse Rating: Double-check that you’re using the correct fuse rating for that circuit.
  • Corrosion or Damage: Inspect the fuse box for corrosion or signs of damage that might affect the circuit.

5. Test Components:

  • Ignition Switch: Faulty ignition switches can cause intermittent power loss. Test or replace if needed.
  • Alternator and Battery: Make sure both are in good working order. Voltage spikes from a failing alternator could cause electrical issues.

6. Use a Multimeter:

  • Continuity Tests: Use a multimeter to check for continuity and find where the short might be occurring in the circuit.

Pro Tip:

  • Consult a Wiring Diagram: A wiring diagram for your specific year and model can help immensely in tracing the circuit and identifying potential problem areas.

If you’re still stumped, you might want to check out community resources like the Bullnose Ford subreddit for additional insights or see if there’s a related video on the Bullnose Garage channel.

Let me know if you need more details on any of these steps!

User avatar
User:

I’ve installed a new solenoid, ignition switch, ICM, rotor, cap, and plug wires — what else could cause the fuse-blow and stalling?

Bill avatar
Bill:

Alright, with those new parts, we can narrow it down further. Since the problem persists, it’s likely an issue with the wiring or connections. Let’s focus on those:

Further Steps:

  1. Re-check Wiring:

    • Inspect New Connections: Double-check the installation of your new parts. Ensure all connectors are fully seated and wires are properly routed.

  2. Trace Wires Thoroughly:

    • Look for Pinched or Damaged Wires: Follow the wires from the solenoid, ignition switch, and ICM to ensure none are pinched or damaged during the installation.

  3. Check Grounds:

    • Verify New Component Grounds: Make sure all grounds related to your new components are clean and secure.

  4. Fuse Box Inspection:

    • Thoroughly Inspect Fuse Box: Sometimes, issues can arise from within the fuse box itself, such as loose connections or internal faults.

  5. Multimeter Testing:

    • Check for Continuity: Use the multimeter again to verify there’s no short to ground in the circuits related to the fuse that’s blowing.

Pro Tip:

  • Consider Heat: Intermittent issues might also be heat-related. Check if any wires are close to hot engine components and could be causing temporary shorts when they expand or shift.

If the problem continues, you might need to go wire by wire. Electrical gremlins can be a real pain, but patience and thoroughness usually win the day.

Keep me posted on your progress!

This answer was written by Bullnose Bill, our AI shophand trained on hundreds of Bullnose-era Ford topics. He knows his way around old Ford Trucks.

As with all of Bill’s answers, it has been reviewed and approved by Ed Zenisek, the man behind Bullnose Garage and a real human being.

While we do our best to keep things accurate, always double-check any repair advice and use proper safety procedures. For real-world walkthroughs and more hands-on content, check out Bullnose Garage on YouTube or visit the BullnoseFord SubReddit.

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