80 series 3FE voltage and electronics issues (1 Viewer)

[Sam Haring]

I recently sold my fj60 and purchased a project 1991 fj80. It ran and drove but it had a hard time starting and its exhaust had a rich fuel mixture. It seemed like it had a hard time accelerating but I am unfamiliar with the 80. After its first 20 mile drive it wouldn't start again.
I took a closer look under the hood and found many faulty wires leading to the ignition system. All 3 distributor wires were spiced twice with twists and the NE signal wire was frayed and touching the metal part of the insulated sleeve. On top of that the insulated oil pressure signal wire was damaged and touching the distributor wires(wire was melted at a connector before the ecu). The other two wires from that part of the harness were cut and loose and I am having a hard time deciphering what they go too. One wire is a thick black with red stripe and the other wire is a thin black with a white stripe. Any help here would be appreciated. Again, these are the wires grouped with the oil pressure signal and the tach.

The wires leading from the harness to the ignition coil were spliced as well as 2 of the wires leading to the igniter. Also in this loom, the condenser wire coming from the tach signal was cut and loose and presumably arced into the steel wheel well. I discovered the efi relay was removed from the box and was only wired to 12v and ground, I still haven't found the real relays location and predict the previous owner bypassed it entirely. This lead me to the fuel pump which was now barely working only when I jump +B and FP. Voltage at the pump was around 8v. Voltage at +B on my diagnostic block was only 11.5v. I am perplexed as to why I have these electrical issues and how they all seemed to manifest simultaneously.

Symptoms:
Cel lights up
code flashed 51 once and stopped
NE pickup coil tested at 31 ohms instead of around 160
Ignition coil tested at .6
AFM seemed to test fine

I soldered and heat shrunk all offending wires, rerouted the condenser wire and bought a new ignition coil and a tested used igniter and I bought a used tested oem distributor. I'm waiting on the distributor to ship currently and will update future findings

Questions:
What should fuel pump voltage be at the tank harness?
Could I have a damaged ecu?
The truck has a push button starter installed instead of a starter relay, could this be a problem?

thanks very much for reading

 

[jonheld]

This truck sounds like a real hack job. I would STRONGLY suggest getting the factory EWD and FSM so you know what things are supposed to be.
Voltage at the B+ terminal of the diagnostic connector, the feed to the FP as well as all sensors on the engine all originate from the EFI relay circuit. You need to figure that out first or nothing will be right.

 

[jonheld]

What should fuel pump voltage be at the tank harness?
Voltage originates at the EFI relay circuit.

Could I have a damaged ecu?
Unlikely since the engine runs

The truck has a push button starter installed instead of a starter relay, could this be a problem?
There is no starter relay on a US spec 80 Series

 

[Dave 2000]

Is it possible it has had a loom fire, and the correct loom was not available, so a lash up was called for to move it?

Pump voltage would be expected as at the battery less a small drop for distance.

ECU's are pretty hardy, difficult to screw one up, are you prone to bad luck?

Regards

Dave

 

[Sam Haring]

Thank you for the expedient response Dave 2000 and jonheld.

jonheld- I found an FSM and cut out the leads to the distributor to test it free from the hacked harness and the NE pick up tested 0 ohms (G+ tested well at 167), I suspect the cracked wiring was crossing the signal and took out the NE. I will trace the efi relay circuit wiring and see what I come up with, I have wiring diagrams now and should be able to come up with some solution. I suspect the low voltage fragged the old fuel pump and potentially causing more damage, a remedy is certainly in order here.

Dave 2000- My gut tells me I have an FJ62 3fe swap in my truck, but relying on your gut for answers can be fool hardy. No fire but the wiring seems dry to the a brittle point in places, my gut again tells me that this is a motor that may have sat out in the dry Arizona heat, hence the weathered harness . I might be lucky, but the facts aren't all in to be honest, but this $1000 fj80 might not share the resemblance. I bought the truck because it had a newish OME HD lift, new A/T tires, ran and stopped after installing the previous owners already purchased parts. Figured at the very least I could part it out, but the truck has something about it and I want to try and bring it back.

 

[Sam Haring]

Wow, I received the replacement distributor and tore down the old one to discover this mess. The NE pick up coil unwound during the last drive and found itself wrapped around the distributor shaft. I pulled out both pick up coils and they immediately fell apart. I have never seen this much corrosion in any distributor, much less a vehicle that was running not to long ago.

The "excellent" condition distributor I bought off some proprietary bidding program was damaged during shipping, rendering the shaft bent and the main body broken. I am currently sorting out the low voltage issue and swapping pick up coils