Real time help: stranded in grand junction, CO

[PabloCruise]

No resistor on igniter:

 

[PabloCruise]

From my 1978 Engine Manual:
I don't know if I have the external resistor or not. I will go find out!

View attachment 3613103

Primary resistance:

 

[PabloCruise]

From my 1978 Engine Manual:
I don't know if I have the external resistor or not. I will go find out!

View attachment 3613103

Secondary resistance:

 

[PabloCruise]

The coil is acting like a resistor model.

 

[PabloCruise]

For purposes of clarity, I disconnected the leads to the primary coil for measurements:

 

[PabloCruise]

I am not sure how definitive those specs are, but they look out.
I might as well clean up all my connections:

 

[PabloCruise]

Primary resistance:

View attachment 3613158

Secondary resistance:

View attachment 3613159

I am not convinced these numbers are the smoking gun I was looking for.

 

[PabloCruise]

The coil can fail with turn to turn shorts or it can just open up. It will change as it heats up. You can get a good spark testing it with an open plug but the spark will be weak when under compression. My old JD 140 with the 1 cylinder Kohler goes thru a coil about every 10 years, due to vibration I think since it is mounted to the engine. It will stumble like it is running out of gas when they fail. The first time I spent a few hours troubleshooting the fuel system before I changed the coil with a spare. It had good spark with the plug resting on the head.

I wonder if a coil would test good when cold, but bad when hot…

 

[Engineer8000]

Yes. that is possible.

 

[PabloCruise]

Yes. that is possible.

That will make testing more challenging…

 

[middlecalf]

Is all that electrical original to the rig?

 

[PabloCruise]

Is all that electrical original to the rig?

Yes.
That is how I got it from the original owner.
The tach signal lead is something I added.

 

[Tomba]

Yes.
That is how I got it from the original owner.
The tach signal lead is something I added.

Some great info in this sub travel thread. Thanks for posting @PabloCruise

 

[PabloCruise]

Is all that electrical original to the rig?

I am trying to figure out if what is on there is correct? There is no external ballast resistor on the coil, just the ignitor pictured above.
From these threads, I might perhaps have a resistor wire in place from the ign switch to the positive (+) terminal at the coil - I need to measure.
Also, what ignitor is that? I see earlier looking ones, and the 60 ones look silver with fins?

I have been reading in here:

OEM coil options - 1978 FJ40

Hi all Trying to source an OE coil for my 78 (Oz market) FJ40 Factory PN 90919-02004 (NLA) Substituted into 90919-02015 (Also NLA) Does anyone know a source for the 90919-02015, or indeed have a substitute PN for it? Many thanks

forum.ih8mud.com

'77 FJ40 - Ignition Coil replacement?

I would like to replace the aftermarket ignition coil on my '77 FJ40 with a Toyota OEM coil. I called C-Dan and understand that the OEM coil #90919-02077 is discontinued. I'd like to stick with OEM parts, but if you can't get them, well, you know............ Has any other '77 owners run...

forum.ih8mud.com

 

[PabloCruise]

I am not sure how definitive those specs are, but they look out.
I might as well clean up all my connections:

View attachment 3613172

I am guessing these crusty connections could have caused me trouble?

 

[PabloCruise]

Some great info in this sub travel thread. Thanks for posting @PabloCruise

Heck yeah! I am thinking I may start a sep thread on coils. We need more threads about coils in here!

 

[Tomba]

Heck yeah! I am thinking I may start a sep thread on coils. We need more threads about coils in here!

Agree. Plus, chicks dig dudes who know about coils.

 

[PabloCruise]

Agree. Plus, chicks dig dudes who know about coils.

Here we go:

Ignition Coil Questions - 1978 Fed Spec 40

I know there are a few coil threads out there already, I have been reading them! I am trying to figure out: What I have on my 40, If what I have is correct? And, is my coil the source of my recent troubles? Last item, if I have to replace my coil, what is a suitable replacement (OEM Toy p/n is...

forum.ih8mud.com

 

[PabloCruise]

Here is the diagram and schematic for the small-cap, electronic distributor for 1978 MY:

View attachment 3613093

I keep trying to move away from this thread, but looking at this scan from the FSM got me thinking - does the ignitor take a signal from the dizzy and then pulse signals to the coil to trigger spark?

 

[fjwagon]

Yep, suppose to be a stronger controled spark is my guess.

On your readings, you get 1.1 ohms on your primary and 13.48 k ohms on your secondary. That don't sound right if your the manual is correct to you fj40. It says primary should be: 2.6 - 4 ohms and the primary should be 6 - 9 K ohms. Almost looks like you have a good coil but the wrong application.....but I need more info before I can say that. Can you still see the part on the coil. I try getting the oem ones.

On a different note, I have seen coils stop working entirely, easy to troubleshoot. I have seen one where it only worked when the engine was cold and fail 20 minutes after it warned up. Have also seen bad wires cause it to back fire. Other times make it look like the rpms go down causing the engine to bog down and not go faster than 45 mph and all of sudden correct it self. And that was one sparkplug wire doing that.