1978 FJ40 Distributor Wiring

[adistler1]

Was trying to replace my clutch slave cylinder. As I was spraying the hose connections with Blaster it slipped from my hands and fell into the engine compartment. It looks like I might have disconnected some wiring to my distributor. I have the red wire coming from the distributor that doesn't have anything connected to it then two bare wires coming out of the harness. Any ideas?

 

[adistler1]

It looks like a white/black wire should go from the fuse block to the distributor from the 78 wiring diagram. There is definitely a whitish black bare wire but also a solid black bare wire. What goes where?

 

[spotcruiser]

It's difficult to say without more info. You don't have the stock distributor, though, unless your truck is non-US. You have the early points or non-US distributor with the octane selector. Are you using an igniter with that distributor? Have you identified when the two wires from the harness have power and where they originate? The wire to the distributor should not come directly from the main harness on the fender; it would typically come from the coil or igniter. When you say harness, are you talking about a 2 or 3 wire harness dropping down from the ignition coil area?

 

[adistler1]

It's difficult to say without more info. You don't have the stock distributor, though, unless your truck is non-US. You have the early points or non-US distributor with the octane selector. Are you using an igniter with that distributor? Have you identified when the two wires from the harness have power and where they originate? The wire to the distributor should not come directly from the main harness on the fender; it would typically come from the coil or igniter. When you say harness, are you talking about a 2 or 3 wire harness dropping down from the ignition coil area?

There is one wire running from the ignition coil to the distributor. I'm not sure what distributor is on here. This was a build by FJ40Jim, so hopefully he can chime in and tell me what to do.

I haven't had a chance to check the 2 wires yet as to when they have power but they are coming out of the firewall on the passenger side. Everything is taped up so I'm not sure I'll be able to trace it through that hornet's nest.

 

[spotcruiser]

Yep, wiring can be a little difficult to follow through a harness. I'd check them to find out when they have power and possibly to identify a specific fuse that feeds them. I'd also clean off each wire a bit so that I could identify the exact colors. Land Cruiser wiring is typically (if not always) two-color; a main color and a tracer color. If the wires are solid colors, they are most likely not stock. You will probably find that non-stock wires will not even be in the harness, which makes hand-over-handing them easier. If you can identify a main color and tracer color, you can probably identify them by the W/D.

So, you already have one wire running from the coil to the distributor and this red wire is a second wire running into the distributor? Do you have an igniter or an aftermarket ignition of some kind? Does the engine start?

There is one wire running from the ignition coil to the distributor. I'm not sure what distributor is on here. This was a build by FJ40Jim, so hopefully he can chime in and tell me what to do.

I haven't had a chance to check the 2 wires yet as to when they have power but they are coming out of the firewall on the passenger side. Everything is taped up so I'm not sure I'll be able to trace it through that hornet's nest.

 

[adistler1]

The starter motor turns but the engine won't fire.

 

[sggoat]

Here's an orig. 78 diagram of the dist--
Hope this helps--

 

[vtgbeemer]

Aaron, this is just a guess but either one or both of those wires were "jerked out" of that empty connector. If those wires look to be the same length and both slide into that empty connector, that is probably where they live. The wiring on your rig is quite a gamble at best so any problem you encounter will be a crap shoot. Do you feel lucky? I would turn the key on and just touch those two together, if you get no sparks slide them into the connector and try starting the engine. Let us know what happens.

 

[spotcruiser]

The problem with the stock '78 wiring diagram, which shows the wiring for the fully electronic distributor, is that his photo in post #1 shows an earlier points distributor.

Here's an orig. 78 diagram of the dist--
Hope this helps--

 

[adistler1]

Aaron, this is just a guess but either one or both of those wires were "jerked out" of that empty connector. If those wires look to be the same length and both slide into that empty connector, that is probably where they live. The wiring on your rig is quite a gamble at best so any problem you encounter will be a crap shoot. Do you feel lucky? I would turn the key on and just touch those two together, if you get no sparks slide them into the connector and try starting the engine. Let us know what happens.

That's kind of what I wanted to do, Craig. I was just unsure about it. I assumed it had to be one, the other or both but was afraid I'd mess something up with trial and error. Thanks!

 

[FJ40Jim]

The wire that has popped apart is the power into the Pertronix module.

Check the two bare harness wires with a DVOM or test light. Color code says they are both ignition power (+12V w/ KOEO). But after one wire was stripped and crimped together, it was found to be dead. So the other wire was tested, found to have 12V ign power. It was stripped and crimped into that connector.
You want to get a new crimp connector and install it on the wire that shows +12V with the key on.

Ignore the other wire because it is broken/cut somewhere up in the harness.

 

[adistler1]

I found the hot wire coming from the harness and put new crimped, shielded connectors on it, however, it still won't start. The starter motor spins and spins, but the engine won't fire. It doesn't even try.

I got the test light out, checked my connection and there is power going through the wire all the way to where the wires connect to the petronix module in the distributor. Still nothing. Just cranks and cranks.

 

[adistler1]

You know, this problem seems an awful lot like the issue I had a couple of months ago with battery drain. I'm going to throw some cable on it tomorrow. It's been cold and the truck has just been sitting. There's a good chance that the issue still isn't fixed an my battery just doesn't have enough juice to get the engine to fire. Fingers crossed.