Only get spark when turning key off or to on position (1 Viewer)

[thejd23]

Hello all, I’ve got a 1967 fj45 that I’m having some issues with on the ignition/spark side, it’s getting fuel, air, and everything else except spark, but it does get one spark when I turn the key back to the off position, I’ve got power to the coil when the key is on but no spark when turning it over, it does have the electronic ignition conversion, I’m not sure where the problem is coming from. I’m suspecting the pickup or the ignition switch, but if anyone has dealt with this before, I’m an open book, I’m lost at this point. Thanks

 

[Steamer]

I’ve got power to the coil when the key is on but no spark when turning it over

Do you have power to the coil while cranking? It could be the ignition switch. You could jump a hot wire from battery to coil and try again.

 

[Steamer]

it does get one spark when I turn the key back to the off position

That makes sense. That is how the ignition system works. When the points open, or when the electronic ignition breaks the circuit, the magnetic field in the coil's primary winding collapses and induces current in the secondary winding which causes the plug to spark.

 

[thejd23]

Do you have power to the coil while cranking? It could be the ignition switch. You could jump a hot wire from battery to coil and try again.

I jumped a hot wire from the coil to the battery and tried cranking with no luck, and it does have power while cranking.

 

[Steamer]

it does have the electronic ignition conversion,

What type? Pertronix pherhaps?

 

[thejd23]

What type? Pertronix pherhaps?

It was on there when I bought it but I believe it is a pertronix or something similar

 

[1969FJ]

It was on there when I bought it but I believe it is a pertronix or something similar

Can you post a picture of the inside distributer ?

 

[thejd23]

Can you post a picture of the inside distributer ?

Yes I will get one in the am when I get back into the shop

 

[rghouse]

Can you return to stock ignition setup and try that? I’m not familiar with that conversion. Napa had a coil (40$) for my late model when I was dealing with spark issues but yours is a decade+ older.

Anything miswired to the coil can throw it off. Check the wiring diagram. The head scratcher in your case is ignition off = spark. Perhaps ignition is backwards or current is flowing the wrong way somewhere down the line.

 

[thejd23]

Can you return to stock ignition setup and try that? I’m not familiar with that conversion. Napa had a coil (40$) for my late model when I was dealing with spark issues but yours is a decade+ older.

Anything miswired to the coil can throw it off. Check the wiring diagram. The head scratcher in your case is ignition off = spark. Perhaps ignition is backwards or current is flowing the wrong way somewhere down the line.

I’ve been through all the wiring when I got the truck, everything ignition wise was fine, and I’ve driven the truck ~500 miles since I’ve gotten it with no issues. I just went to start it one day and nothing, I didn’t have time to work on it today but hopefully I’ll be able to diagnose a little tomorrow, even if I have to use a parts store universal ignition switch to see if that fixes it

 

[kerplunk]

Check the voltage on the battery when it's cranking.

While it might seem high enough with no load, it will drop under the load of the starter. Not sure what a normal number actually is though.

If it's too low, electronic stuff will stop working....

 

[45Dougal]

The fact that when you switch it off, you get a spark, indicates that the coil and connections to it are at least working correctly.
The problem therefore seems to be in the switching side.
Id check inside the dizzy to see if the shaft is worn (floppy in the bearing) or the pickup has moved (the distance to the trigger can be fussy). Check its all tight and good clearances.
...And take photos to help the next guy fix it quicker

 

[thejd23]

Can you post a picture of the inside distributer ?

Sorry for the late reply, been out of town for work all week

 

[45Dougal]

Sorry for the late reply, been out of town for work all week

View attachment 3428525

The black wire at the bottom is not crimped correctly, so might be worth a check, probably fine though as it looks to be soldered to the nut.
Is the screw tight?

 

[Rocky_LC]

Agree with 45D.

The fact that you get a spark when you switch the ignition off means the coil is charged.

That is pretty typical. What causes the major spark is an interruption in the voltage to the coil, once the coil is charged.

It has to be in the “interruption” portion of the circuit, not the power supply to the coil, I.e. the part in the distributor, or wiring of that portion of the circuit.

Rocky

 

[thejd23]

Hello to all that may have this issue now or later down the road. I’ve been away from the Land Cruiser for a few months now, life just gets in the way sometimes, but I diagnosed it as a bad igniter, so I ordered one from pertronix and got her back on the road, along with a new slave cylinder for the clutch, thanks for the help