PerTronix Coil only at 8.6V?

[brw1994]

Hey, been around this forum for a bit now but never needed help till now. I have recently installed a PerTronix Flame-Thrower 3.0ohm coil and electronic ignition. Today I was about to throw out a pamphlet of instructions from the coil and had a quick read over and I didn't do the last thing n the list, check the Volts that are coming from the coil and whether I had a resistor or not. Turns out I should be getting 12V from the reading and I'm only getting 8.6. Has anyone got any idea where I can get an online copy of how to counteract this or know themselves?

Thanks.

[taslucas]

I have the flame thrower2 coil and it doesn't need a resistor. I had problems with my ignitor module (was faulty from the factory). They sent me test instructions for the module and the negative ground test for the coil. I can send them as a PDF if you want? But it sounds like you already know that it's not putting our enough volts. Maybe you don't need the resistor? Do you have an ignition module, and if so, does it seem to be working correctly?

Tap, crackle, pop

[brw1994]

I wouldn't know really because I haven't been able to do timing on the car after installing both items. But I have the lobe sensing electric ignition module and the coil but what comes of me only having 8.6 volts am I not getting full bang for my buck kinda thing?

[taslucas]

Is your battery putting out 12 volts?

Tap, crackle, pop

[Yendor]

If you still have your ballast resistor fitted this will be why the voltage is low at the positive side of the coil......or are you measuring on the negative side of the coil?

[brw1994]

Ok i've been away for schoolies but I'm back now. I did a few tests this arvo to try and work out whats happening.

I have 4 wires running to the negative side of the coil and 2 running to the positive.

Negative:
Blue and Pink & Blue and Silver, both dissapear in a loom to I don't know where
White and Black Stripe, runs to the 12v Gas unit
Blue, straight to the ignitor

Positive:
Red, ignitor
Thick Red wire to the ballast resistor.

Now here's the thing, If I test the volts from the Thick Red wire coming off the resistor I'm getting a 12v reading so by rights I should be getting 12v through the coil? But I just had a brain wave, does the resistor earth itself? Because when I take the wire that runs to the resistor and go straight to the coil I still only get 8v. Why is this so? Do I need to run the other White with Black stripe on the resistor to the negative on the coil?

P.S I get 12v from the coil when I run 12v from the battery the to positive on the coil.

[taslucas]

I'm pretty sure that your ment to remove the resistor when fitting that coil. Double check that. Mine is the flamethrower 2 coil and the instructions are to remove tv ballast resistor.

Tap, crackle, pop

[Yendor]

Now here's the thing, If I test the volts from the Thick Red wire coming off the resistor I'm getting a 12v reading so by rights I should be getting 12v through the coil?

With the engine running, on one side of the resistor you should see about 12 volts on the other side of the resistor you will see the 8 volts. At the positive side of the coil you will also see 8 volts.

The resistor is in series with the coil. There is a wire that links the positive side of the coil to one side of the resistor.


But I just had a brain wave, does the resistor earth itself?

No



Because when I take the wire that runs to the resistor and go straight to the coil I still only get 8v. Why is this so?

Because the resistor is still in series with the coil. If you did this with the other side of the resistor you will see 12 volts at the coil.




Do I need to run the other White with Black stripe on the resistor to the negative on the coil?

NO.....The original White with Black stripe large wire at the resistor is the 12 volt feed from the ignition switch. If you connect this to the negative side of the coil you will more then likely blow up your electronic ignition module.




P.S I get 12v from the coil when I run 12v from the battery the to positive on the coil.


If the fitting instruction say to run it without the ballast resistor all you need to do is bypass it.

The easiest way is to take the wire from one side of the ballast resistor and connect them with the wires on the other side of the ballast resistor.

[brw1994]

Yeh it's all sorted now Yendor thanks mate. I figured out that was a live wire so it didn't end up on the negative side it ended up on the positive and it fixed the whole issue. I'm now getting 10 - 11v better than 8

[Robo]

Yeh it's all sorted now Yendor thanks mate. I figured out that was a live wire so it didn't end up on the negative side it ended up on the positive and it fixed the whole issue. I'm now getting 10 - 11v better than 8

Is that correct 10v on a 12v system?.
From a wire that's coming via ign switch from the battery.
shouldn't it be reading 12v ?.
Or is it weak voltage and needs fixing with a direct power via a relay, and using the old power supply cable as the new switching source for the relay ?.

[brw1994]

I don't know I haven't run over it again but I think my battery was low when I was doing it from constantly checking etc ill check again tonight

[Robo]

I don't know I haven't run over it again but I think my battery was low when I was doing it from constantly checking etc ill check again tonight

I would hazard a guess my results of 10v are accurate.
Checked coil engine running, coil positive pole to an earth making only 10 volts.

I only charged mine a couple of days ago, and the smart charger shows 100% charge, not a cheapy charger.
The battery cranked the motor over last week comp testing with flying colours, 14 cylinder checks x 8 compression strokes each, and my charger afterwards recorded batt dropped to only 80% capacity, convinced my AGM battery is A ok.
I'm wondering, is the voltage drop to 10 volts the way it's supposed to be ? , I would think that's not the case.
cheers

[brw1994]

Yendor should know he's a tip top auto sparky, IDK if it's his trade but damn he's smart..

[Robo]

Ignition contacts read 12 volts on input and start, ok good result.

Engine off and test position contacts,
Ign position run and ballast resister contacts read 5.75 volts.

engine running diff readings mine 10v and your 8.6v may just be your suss battery and or genuine to a/market ballast .

[happygu]

Not sure what is inside the unit itself, but you will lose half a volt going through a diode, so if there is a few diodes inside, would could well only read 10V at the output

[Robo]

Not sure what is inside the unit itself, but you will lose half a volt going through a diode, so if there is a few diodes inside, would could well only read 10V at the output

Ballast resistor seems to be dropping voltage to 10v at coil while engine running.
ok, that sounds about right ,as that's the purpose of a resistor.

And there should be 12v when starting, as the resistor is bypassed while starting engine.

I only wanted to know is 10v correct while running ?.

[Yendor]

On a vehicle with a ballast resistor fitted these are the voltage readings you should see (negative lead of your voltmeter connected to the negative of the battery and engine running).

The ignition supply to the ballast resistor (The White wire with a Black trace on Patrols) 12-14 volts.

The other side of the ballast resistor 8-10 volts (Red wire on Patrols)

The positive side of the coil 8-10 volts (Red wire on Patrols) This should be the same reading as the second side of the ballast resistor, they are linked by a wire.

On a vehicle with no ballast resistor fitted (or resistance wire) you should see 12-14 volts at the positive side of the coil.

There is no real use in measuring the negative side of the coil. If the engine is running you know the points are opening and closing or the trigger module is working. Plus your multimeter will be way too slow to get an accurate reading you will need a scope.

Things to remember when using a multimeter.

Most of the multimeters that we use are at the lower end of the scale and more then likely have never been calibrated since it was manufactured so they might not be reading 100% correct. If you get a reading of half a volt lower or so, then it not going to matter.

How is the battery in your multimeter? does it need replacing? If the battery is old and getting flat it will cause the multimeter to give an incorrect reading.