SOLVED - Died while driving - fusible link blown (1 Viewer)

[lumbee1]

A week and a half ago coming home from a friends house, the Cruiser suddenly died on me when I made a right hand turn. There was no stuttering or anything. I rolled to a stop and tried to start it again. It cranks but never fires. It was dark and I couldn't see that well. I called AAA and they towed me the full 1/4 mile to my home.

I've checked the EFI relay and the Fuel Pump relay with new units. I've carefully removed the "factory" alarm and installed a new fusible link. There were no signs the fusible link was burnt or bad. The truck started immediately however after driving less than 50 yards, I made a right hand turn and it died again.

I had a friend pull the Cruiser back home so I could begin testing. I examined both the original fusible link and the new fusible link. The AM2 link (gray connector) was blown on both of them.

I ordered a new DMM to test the ignition coil. Initially I thought I had my smoking gun when the coil tested bad on both the primary and secondary coils. I ordered a new coil that arrived today only to find out the new DMM is bad and not the coil. Now I have a trail spare and I've got to get another DMM.

I know that most shorts occur due to the EGR pipe burning a hole in the harness and shorting the wires. I removed my EGR pipe in 2017 and my harness looks great with the factory wrapping still on it.

I need some ideas on what to check next.

I have the 96 FSM and I'm looking over it now.

 

[MoJ]

You’ll receive several good suggestions. A quick one to check is the wiring harness that exits the ecu and then rubs against the metal support near the bottom of glovebox opening, eventually wearing through the insulation.

 

[lumbee1]

I'm all about pictures. The thick covering over the wires was still intact. Underneath I had to push the same black covering out of the way to view the wires.

With no EGR pipe, I have lots of room around the engine harness.

 

[lumbee1]

The tear in the wrap around the harness was done by me earlier. The wrap was intact but I pulled on it just to examine the wires. The wrap is very fragile and tore easily.

 

[inkpot]

Does the Check Engine light come on breifly when you first turn the key to the RUN position?

 

[lumbee1]

Does the Check Engine light come on breifly when you first turn the key to the RUN position?

Fusible link AM2 is currently disconnected. I have two spares that I picked up today.

 

[bigredmachine]

if you have access to a ewd youll want to check out the power source page and see what gets powered by the am2 in the fuseable link to start checking chasing down your short

 

[MoJ]

You’ll receive several good suggestions. A quick one to check is the wiring harness that exits the ecu and then rubs against the metal support near the bottom of glovebox opening, eventually wearing through the insulation.

I’ll add that I’m a fan of the braided split loom such as the below for any situation wear abrasion of wire insulation is a concern.

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[lumbee1]

I made a jumper wire with spade connectors and a 15A fuse attached to AM2 connector. With the key in, ACC is fine but turn once more to On and my fuse pops. I will check the EWD to see what gets energized with key at On.

 

[bigredmachine]

am2 powers your injectors, igniter, coil, ignition switch and other stuff. check in the circled area for your issue, they are all powered by the am2

 

[fourtrax]

Might check for a loose alternator wire.

 

[lumbee1]

I'm closing in on the issue. Blade fuses are cheap so I built this little guy.

Thanks to @Kernal 's similar experience with his truck dying, I tore the cover off the harness.

From reading and my own experience, the outside can look normal, but the wires inside the bundle can get melted and the only way to find them is to remove or fully open the wrapping and dig into the wire bundle a bit.

The fact that it died while turning says, obviously, that there is a short somewhere, and the main thing that moves when you go around a curve is the engine I think, so it makes sense it's a wire bundle that is connected close to the engine (seems to be logical).

Some, like me, it's the harness bundle near the EGR pipe. Mine occured when I accelerated after taking a right turn onto a highway on ramp, as soon as I tried to accelerate (movement of the engine?) the engine shut off and the alarm started blaring and lights flashing.

It was melted and shorted wires inside that harness section, but the mechanic totally missed it for a week, and tried bypass the short (not knowing where the problem was) until he opened up that harness.

I removed the harness tape and setup my jumper. With the key in the ignition, the wife turned it to the ON position. My blade fuse didn't pop. Success. When I grabbed the harness and moved it, the blade fuse popped indicating the short is in the wire bundle.

The black residue on the wires is the tape. I need a solvent to clean the wires but not melt the jackets. Any ideas?

 

[lumbee1]

Well, things have not progressed well. I did not find the short and and now cannot recreate the issue with my jumper and fuse. I've tried shaking the harness and pushing the wire bundle around. Nothing seems to work. While this might seen good news, it also means the Cruiser will run but could short the fusible link and die at any second.

 

[lumbee1]

SOLVED!

My harness looked great and I couldn't find anything wrong with it. Injector #6 also looked great. While I was in there, I decided to check injector #5. After removing the connector (and breaking the tab) I noticed the plastic covering over the wires was worn in one spot. That wear spot was also up against a nut on the valve cover. I lifted the wire and briefly saw bright copper in the hole. I cut back the covering and found not one issue but three. Both wires going into the connector were completely exposed.

I've got to get some quality electrical tape and some liquid electrical tape to fix the short and exposed wires.

I hope this thread helps others in a similar situation.

 

[Sc0-]

Would only hope that one day an aircraft electrician might get bored one day and make a bunch of harnesses for the 80 series with OEM connectors...

 

[bigredmachine]

I need a solvent to clean the wires but not melt the jackets. Any ideas?

throttle plate cleaner.

also I would think that it may just be easier to get a pig tail with the connector and just splice it in instead of trying a repair or just taping it up. just taping it is fine as a temporary fix but it will lead to corrosion and issues down the road

 

[lumbee1]

There were four sections of exposed wire on injector #5 connector wire. I taped up the two shorts and then applied a double layer of friction tape. I used liquid tape on the exposed wire at the connector itself. The final step was to zip tie both wires for injector #5 and #6 to the main harness to pull them into the channel away from metal surfaces. Both injector #5 and #6 were cleaned and diaelectric grease applied.

The main harness was wrapped with friction tape followed by DEI Cool Tape.

 

[lumbee1]

Big thanks to @Kernal and @bigredmachine for pointing me in the right direction. This fix would have been free if I discovered the source sooner. It's good to have trail spares though.

 

[Kernal]

Glad you found and fixed the problem.

FWIW: I use CRC Electronics Cleaner, regular tall can (lots of pressure, wear eye protection) or the quick dry (QD) version) when working with wires, connectors, etc.

 

[inkpot]

Would only hope that one day an aircraft electrician might get bored one day and make a bunch of harnesses for the 80 series with OEM connectors...

Still available from dealer, AFAIK.