No spark at coil

[Malleus]

I have a 1977 with a new Pertronix 1.5-Ohm coil and an unknown ballast resistor and igniter. I have no spark from the coil to any ground when the key is in the START position.

I have 12.56VDC at the battery. I have 11.75VDC at the (+) coil terminal and (-) battery terminal, with the key in the ON position. I have continuity between the W/B ground wire at the coil bracket and the battery (-) terminal. I have 12.56VDC at the upstream end of both green connectors, with the key in the ON position.

I have tried to bypass the igniter, by connecting the (+) coil terminal directly to the battery and by connecting the ballast resistor (+) terminal to the battery. No spark with any connection.

I'm stumped. Any suggestions?

Here is the evidence:

 

[B y r o n]

I would check for spark at a plug when cranking and not at the coil.

 

[Malleus]

I would check for spark at a plug when cranking and not at the coil.

Thanks. That didn't work either. That's why I went back to the coil. I'm trying to find the golden screw that's preventing the spark from showing up at the plug.

 

[1969FJ]

Try bypassing ballast resistor as well.

 

[Malleus]

Try bypassing ballast resistor as well.

I tried that, first. Then I tried bypassing the igniter, by connecting the coil, through the ballast resistor. No luck there either.

What I haven't tried is connecting the coil to the battery, without any connection to either the ballast resistor or igniter. I can't think of how that would matter, but I mention it for the sake of completeness.

 

[Pighead]

What I haven't tried is connecting the coil to the battery, without any connection to either the ballast resistor or igniter. I can't think of how that would matter, but I mention it for the sake of completeness.

So, obviously, what you need to try next.

 

[Malleus]

So, obviously, what you need to try next.

So other than the fact that I haven't tried that, what would be the difference in the two connections?

 

[Pighead]

what would be the difference in the two connections?

I have absolutely no idea. I do know that i ran a Pertronix for many years with just a coil.

 

[Malleus]

I have absolutely no idea. I do know that i ran a Pertronix for many years with just a coil.

OK, but I'm not there yet. I'm still trying to get spark out of the coil, so I can then determine whether I have a working distributor...I have a PerTronix module on the shelf, waiting for its turn in the barrel.

 

[B y r o n]

You may have a bad coil, it needs to be tested. Just because it has voltage going in does not mean and can transmit voltage going out. Testing will tell you if it is bad.

This may help with the test process.

 

[Malleus]

You may have a bad coil, it needs to be tested. Just because it has voltage going in does not mean and can transmit voltage going out. Testing will tell you if it is bad.

This may help with the test process.

I have two coils on hand, the new PerTronix (1.5-Ohm) and the OEM coil (1.5-Ohm) which was on the 40 when I got it. I have tested both coils, prior to starting this exercise. They are both good and neither produces a spark.

 

[Steamer]

How bout hooking up the Pertronix “Ignitor” without the Toyota “igniter” like Pighead mentioned and how I also ran mine for years. With your 1.5 ohm coil you need to use the resistor. If you bypass the resistor, only do it for starting.

 

[Pin_Head]

The coil only makes a spark when the + is energized and the - side is momentarily ungrounded. Disconnect the wire at the - side and see if it makes a spark when grounded. If so, there is a problem at the - side, such as it is always grounded.

 

[Malleus]

How bout hooking up the Pertronix “Ignitor” without the Toyota “igniter” like Pighead mentioned and how I also ran mine for years. With your 1.5 ohm coil you need to use the resistor. If you bypass the resistor, only do it for starting.

View attachment 3016168

That's my plan, eventually. Right now, I'm stuck at "the coil won't produce a spark", so simply replacing the points with the PerTronix signal generator doesn't help me. At this point.

 

[S.CarolinaFZJ80]

I went through this on my '79. Ended up being a bad ignitor box. Do you have another one to swap in?

 

[Malleus]

The coil only makes a spark when the + is energized and the - side is momentarily ungrounded. Disconnect the wire at the - side and see if it makes a spark when grounded. If so, there is a problem at the - side, such as it is always grounded.

So, I have connected the coil to the battery, via the harness, so that the key and ENGINE 15A fuse are inline. The load resistor was not in this test circuit, and the engine was not started; I used only the key ON switch to activate the circuit. I'm also using the battery (-) terminal as the ground point, to minimize any resistance in the circuit.

The coil does produce a spark, although a very weak one - the sparks at the (-) coil terminal when I connect/disconnect the circuit are much more pronounced. That tells me that at least the harness, with respect to the power supply circuit, is not at fault.

So now I'm looking for a ground fault. It's possible that's in the igniter module.

At first I thought that the rust between the coil bracket, where the harness is grounded, and the igniter was at fault, but if I'm looking for a continuous ground, that can't be it, since that would have been a open circuit.

FWIW, the coil passed the resistance check in spec, 1.6-ohms between the primary terminals and 11.9-kohms between the primary (+) and the secondary (-) [my FSM says between 0.5 and 0.7-ohms between the primary terminals, which is puzzling because it's a 1.5-ohm coil (typo?), and 11.5 and 15.5-kohms at the secondary terminals. The primary coil wire (the one between the coil and distributor) measures 1.2-kohms, which is less the maximum 25-kohm allowable.

 

[Malleus]

I went through this on my '79. Ended up being a bad ignitor box. Do you have another one to swap in?

Unfortunately not. I'm holding out for a hail Mary from David Miller.

 

[Malleus]

So, after a little fiddling, here is what the innards of a 89620-60012 igniter looks like:

No printed circuit board, just a breadboard. Or maybe a cracker board, it's pretty small.

As advertised in the EWD, two resistors (18-ohm & 100-ohm, if my electrical shop learnin' from high school hasn't failed me), a pair of capacitors (EQC01-170) (the EWD says one diode) and two transistors (NipponDenso 05Q06 TP5022 and Sanyo B509N 6G). The 18-ohm resistor is inline with the ND transistor and the 100-ohm is inline with the Sanyo. The black wire goes directly to the coil (-); the other four wires are connected to a 15kohm transformer coil, mounted under the hood of the igniter, upstream of the ballast resistor and coil, resp.

The undisturbed creature, fresh out of its natural habitat:

Everything demounted, ready for disassembly:

 

[S.CarolinaFZJ80]

No smoking gun there.
There wasn't with mine either.
You might be able to send it off to @Engineer8000 at Cape Fear Electronics for check / repair

 

[1969FJ]

So, after a little fiddling, here is what the innards of a 89620-60012 igniter looks like:

View attachment 3016387

View attachment 3016389

No printed circuit board, just a breadboard. Or maybe a cracker board, it's pretty small.

As advertised in the EWD, two resistors (18-ohm & 100-ohm, if my electrical shop learnin' from high school hasn't failed me), a diode (?) (EQC01-170) and two transistors (NipponDenso 05Q06 TP5022 and Sanyo B509N 6G). The 18-ohm resistor is inline with the ND transistor and the 100-ohm is inline with the Sanyo. The black wire goes directly to the coil (-); the other four wires are connected to a 15kohm transformer coil, mounted under the hood of the igniter, upstream of the ballast resistor and coil, resp.

The undisturbed creature, fresh out of its natural habitat:

View attachment 3016404

Everything demounted, ready for disassembly:

View attachment 3016407

I thought the whole purpose of Pertronix was to replace the igniter , so why use it.

https://images.carid.com/pertronix/products/pdf/1183-installation-instructions.pdf