Bypassing ballast resistor / Operation

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I've got points and condenser coming in today will try and report back

But if my coil isn't putting out a spark nothing else would matter, right?
 

fjwagon

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Yup. You said you are getting 12.3v at battery and 11.6v at the ballast resistor. And about 6 volts at the coil. This may be why the coil is not working. It would seem the resistor is at 1.9 ohms according to my math. Oem spec should be 1.3- 1.7 ohms which will give you about 7 -9 volts at the coil.... depending on the resistor ohms and if you have 12 v. I don't like to see 11.6v, should be higher. I suggest cleaning both ends on the + and - battery cables at the battery. If it does not have jumper ground from the frame to the starter I would install one. If it does clean both ends. Hopefully you can get it around 12.v. to the ballast resistor. Also good solid connections though out the circuit will help. I always follow tolerances the OEM.
 
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I'll check all the connections again.

So I did do some work to it which I thought was unrelated but maybe not. Replaced the rag joint, but I had to unbolt the steering column and drop it down and had it moving around quit a bit. I wonder if something with the ignition switch or another connection could of gotten messed up.
 

fjwagon

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I hear you brother, You can try checking the voltage before it does into the ignition switch. These 40 are old but once you get all the bugs out, they are very dependable. It may need a lot of cleaning of contacts and terminals, visual checks on the wiring. The fuse box is another area of interest but once start checking voltages you will have a better idea what to do.
 
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Not sure what year yours is, or if the dizzy etc is original, but the 1978-80 has a ballast resistance wire in the harness. If it has this wire it may drop the volts a bit . 11v with no load for example.
If this ballast wire is wired in series with another ballast resistor , it will drop the voltage too much.4- 6v under load from the coil for example.
 
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I hear you brother, You can try checking the voltage before it does into the ignition switch. These 40 are old but once you get all the bugs out, they are very dependable. It may need a lot of cleaning of contacts and terminals, visual checks on the wiring. The fuse box is another area of interest but once start checking voltages you will have a better idea what to do.
It's never had a single problem and now this all of a sudden. Fuse box was replaced when I got it a few years ago.
It's a 75 btw.

New coil, points, condenser, wires, ballast resistor, ignition switch and still nothing.
Not sure if that's bad or not but they're cheap so got replaced

20220105_182901_HDR.jpg
 

fjwagon

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Some of the components had be replaced, no doubt. Your voltage needs to be a little higher. Your ignition switch may going bad. Check the voltage there. You can jumper a ground directly from the battery to the coil and see if the voltage improves.
 
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fjwagon

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The other thing to watch for when installing the points and condenser make sure it does short our to the casing of the distributor. This happens more often then you think. You can check it by using a lamp or test light. Rotated it by hand and for the lamp to come on. Again if make sure the lamp will actually come with voltage you have. If it's a 12v lamp don't expect it to come on at 6 volts.
 
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I got one of those cheap [$50ish US] ebay 2f-3f reluctor type non-points dizzies and it works great so far. Set the timing and forget about it. Has only 2 wires and hooks up the same as the points one. I keep the old points dizzy in the truck for emergencies . Quick and easy replacement for the points.
 
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Laying in bed last night I remembered I forgot to put the rotor back on when I replaced the points.

That was too easy though, still nothing.
 
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That I haven't tried. Mentioned it earlier I think then someone said it could damage something. From what i've seen for a short period is fine.
I will try it later.
 
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@fjwagon @pthicus the cap looks good

Ok so I can get spark from the coil when I wire directly to battery. If I go ignition switched 12v directly to + on coil it's a very weak spark.
Will I damage anything If I try to run it with battery voltage right to coil?
 

pjohnson

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As I recall, some coils take 12v input. It sounds like you have some poor grounds in the system.

You could run switched 12v to power a relay that provides a direct 12v to the coil, or to a new ballast resistor to the coil.
 

fjwagon

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The idea was making sure the points and condenser was not shorting out to distributor. The other concern I see is the voltage is to low. We have to figure that part out. You have voltage drop before you get to the ballast resistor. And than after the ballast resistor it's way to low. I was hoping that cleaning both ends on the battery terminals would help the voltage go up. So than I suggested jumpering the ground to the coil from the battery And see if the voltage goes up. The other thing I wanted to suggest was run a jumper from the + of the battery to ballast resistor. All this suggestions are done in steps hoping you find the culprit.

I'm starting to think the reason the condenser was installed at the coil was to fix this low voltage issue. In electronics we usually see capacitors used to filter out "noise" or keep big surge out. And to avoid a bad signal which causes many other issues. And the other is to send a surge of current to start ac electric motoris one example.

The last thing I will say is you may want start a log on what you have done....you have done a lot of stuff to it. It may not seem like progress but it is. Just hang in there. Take a breather sometimes that helps.
 
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Ok so I got it running. Along with everything above, I went out and triple checked every connection, re-did some and new wiring.

Started up easier than it ever had. Replacing stuff isn't usually the best approach but it got a tune up in the process so can't be too mad lol

Thanks for all the input again.
 

fjwagon

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Sweet. Replacing those items needed to be done. It needed to be done sooner or later. Nothing last forever that's for sure. The Toyota OEM is very helpful especially the fact that the tolerances given actually help in figuring what needs replacing. I admit It can be overwhelming at times but it's not rocket science my friend. On another note I would suggest writing a date on the condenser and keeping a spare set points with the gap written on the box. You can even find something with the gap and drop it in the box.
 

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