89 B2 died on the highway and never started back up

[89kcmob2]

So I've had good luck with my Bronco II so far. I've had it on long road trips (5 hours each way). It was relatively low miles when I picked it up, under 100k with records. I've swapped out almost all of the easy stuff from sensors to shocks.

On a recent trip, after making it the full 8 hours out –with a few days in between– it suddenly died on the highway in the 5th hour on the return trip.

Here's the weird stuff. When I turn the key to run, everything electronic works just fine. However I don't hear the fuel pump pressurize. Now that would tell me it's the fuel pump IF when I turned it to start the starter actually cranked. It doesn't. However, the starter will run if I bridge the two nodes on the solenoid with a screwdriver.

Something is causing both the starter and the fuel pump not to run.

I've replaced the ignition switch, the ignition relay, and the fuel pump relay. Nada. I've read about the TFI issues but that doesn't seem like it fits the bill. What else could be going on?

 

[gaz]

89kcmob2,

If it doesn't crank at all:

1) measure your battery voltage
2) inspect the power cable to the starter and the connection on the starter. They can actually loosen.

 

[bobbywalter]

Could be in the neutral start circuit

Could be the fitting on the post that goes to the starter ...it has a primary wire and secondary to the starter in it.

May just be a loose or burned ground to the pump relay....this assumes the check engine light comes on.

Check the pcm ground at the battery careful. Pull it apart and reassemble



All fuse good is the other assumption

 

[89kcmob2]

Oddly, no check engine lights yet.

Battery tests at 12.6. Keep in mind I can get the starter to crank by connecting the two nodes on the solenoid. It's just not cranking when I turn the key.

All fuses have been checked. I've heard of people replacing fuses even though they weren't blown, maybe I need to try that.

Neutral safety switch had crudely been bypassed by PO. But was operating just fine in that condition for a good while before this event. I'll try hunting these connections for loose grounds, etc.

Thanks y'all.

 

[RobbieD]

I've replaced the ignition switch, the ignition relay, and the fuel pump relay.

You replaced the electrical ignition switch down lower on the column, and not the ignition key cylinder, right?

The electrical ignition switch (where the wiring harness plugs in) on the older Rangers had a tendency to separate after some aging, and the symptoms you describe could be caused by a failing switch.

Beyond that, and what you've done to this point, I'd next start looking at the wiring harnesses and ground points for looseness, corrosion or damage. Check these same things at the computer in the pass kick panel, and it wouldn't hurt to pop open the ECM and look for corrosion or leaking capacitors.

Good luck!

 

[RonD]

It would be long odds that a fuel pump would stop working once running, so probably not the issue
So either spark stopped or injectors stopped, or 12volt power was cut
But neither of these share wiring with START circuit

You can manually ground the fuel pump relay in OBD1 vehicles
Find the OBD1 plug in, should be passenger side engine bay near firewall on main wiring harness to computer in the cab
Look at the drawing of the OBD1 connector here: https://www.therangerstation.com/tech_library/OBD_I.shtml

The Fuel Pump slot is labelled
GROUND that slot, this will ground fuel pump RELAY full time, computer normally grounds it
Turn on key and you should hear fuel pump running
Pull out Ground jumper and it should go off, put it back(key on) and it should run again
This is testing if the fuel pump relay has 12v from EEC relay

If fuel pump is running when slot is grounded you can try to START engine by jumping starter relay again
To see if spark and injectors are working

On the starter relay there are 2 larger posts, the one with battery Positive cable will have several other wires on it, this post is the 12volt Power Distribution for the whole vehicle
Alternator is connected there, Fuse Boxes, every system get 12v power from that post, but from different wires on that post
These wires are often Fusible Links, and can blow like a fuse, but they separate so easy to see if they "blow", except they are often taped up or in a wire loom
So you can lose some 12v power in some circuits but not others

 

[89kcmob2]

You replaced the electrical ignition switch down lower on the column, and not the ignition key cylinder, right?

Yup, that's the one I replaced.

 

[89kcmob2]

Here's the end to the mystery: a wire running from the ignition to the starter had come in contact with the driver side exhaust manifold. This melted off the insulation and faulted some other wires including the turn indicators.

Somehow the fuel pump was also dead, not sure if this wire melt/fault situation did it in, I'm just repeating what the mechanic said.

So there you go, trace your wires.

 

[RonD]

Thanks for the update and FIX

 

[ecgreen]

Here's the end to the mystery: a wire running from the ignition to the starter had come in contact with the driver side exhaust manifold. This melted off the insulation and faulted some other wires including the turn indicators.

Somehow the fuel pump was also dead, not sure if this wire melt/fault situation did it in, I'm just repeating what the mechanic said.

So there you go, trace your wires.

Thank you for the fix! So many people ask questions and never report back. Well done!