no spark...I think? ...Anyone live in Frederick? (1 Viewer)

[Devilmans Hand]

Uh oh. Ignitor voodoo?

What type of ignition are you running?

 

[emorth]

The purpose of the resistor is to drop the voltage to the coil while the engine is running. When cranking the engine the resistor is bypassed to give the coil the full battery voltage. When cranking the engine, the battery voltage drops from the load of the starter motor just when you want the hottest spark to start the cranking engine. This is why the resistor is bypassed and full battery voltage is applied to the coil to create the hottest spark to help start the engine. After the engine starts, the resistor is in series with the coil to reduce the voltage to the coil so the coil runs at a lower voltage (6 - 9 volts) which is good enough for a running engine and the coil doesn't overheat. The wire from the ignition switch (start position) that goes to the starter motor solenoid also goes to the coil so when the solenoid is powered (engine cranking) full battery voltage is also applied to the coil.

Hope this helps,
Ed

 

[emorth]

One more thought... it is not uncommon for resistors to fail when they get hot.

 

[Stumpalama]

Boom. Ed dropping knowledge like Galileo dropped an orange.

 

[emorth]

The wire from the ignition switch (start position) that goes to the starter motor solenoid also goes to the coil so when the solenoid is powered (engine cranking) full battery voltage is also applied to the coil.

After I read this again it needs a better explanation. There is a wire that goes from the ignition switch to the solenoid and a wire that goes from the ignition switch to the coil. When the ignition switch is in the start (or crank) position, both wires have battery voltage on them. There is no direct connection between the solenoid and the coil.

Sorry for the confusion. I should proof read before I post.

 

[emorth]

Boom. Ed dropping knowledge like Galileo dropped an orange.

I'm dropping something. Not quite sure what it is.

 

[DustyFJ]

The purpose of the resistor is to drop the voltage to the coil while the engine is running. When cranking the engine the resistor is bypassed to give the coil the full battery voltage. When cranking the engine, the battery voltage drops from the load of the starter motor just when you want the hottest spark to start the cranking engine. This is why the resistor is bypassed and full battery voltage is applied to the coil to create the hottest spark to help start the engine. After the engine starts, the resistor is in series with the coil to reduce the voltage to the coil so the coil runs at a lower voltage (6 - 9 volts) which is good enough for a running engine and the coil doesn't overheat. The wire from the ignition switch (start position) that goes to the starter motor solenoid also goes to the coil so when the solenoid is powered (engine cranking) full battery voltage is also applied to the coil.

Hope this helps,
Ed

yes, so much. I now at least sort of understand understand how it is supposed to work. After reading some more on other threads I may be more confused than ever. The truck didn't have an ignitor or external resistor bolted to the side of the coil like I have seen in other posts.

uggg.

I posted more pics and started a thread here
https://forum.ih8mud.com/threads/no-spark-what-next.870505/

 

[emorth]

Can you post a pic of the inside of the distributor showing the points/electronics?

 

[DustyFJ]

Uh oh. Ignitor voodoo?

What type of ignition are you running?

whatever electronic ignition that comes in a troll hole dizzy

 

[Stumpalama]

Ed needs a cleaner close-up of the inside of the dizzy, I think.

 

[Stumpalama]

BTW, Ed used to teach automotive electronics. He knows his stuff and is one of the best guys to have on the case.

 

[rkymtnflyfisher]

Fredneck huh? If you haven't made any progress on this by the weekend I may be able to come down and lend a hand.

 

[DustyFJ]

Can you post a pic of the inside of the distributor showing the points/electronics?

little closer

 

[DustyFJ]

Fredneck huh? If you haven't made any progress on this by the weekend I may be able to come down and lend a hand.

That would be awesome, I didn't do anything with it today, not even sure what to do next really.

If my "new" 12v coil went bad. then running the truck with the older coil that requires the external resistor would start the truck but burn the coil pretty quickly????

Maybe I just need to order the right coil??

 

[jcj_78FJ40]

so, truck doesn't run again, sound as if spark is gone.

Are you sure it's the spark?

My favorite initial test is a shot of starting fluid in the carb to see if it fires.

And I also have one of these;
http://www.autozone.com/test-scan-a...oem-in-line-ignition-spark-tester/900800_0_0/

You can check the spark at the cap and the plugs.

And just because I have done this more times than I like to admit......
If you have removed the spark plug wires, double check that they are correct

 

[emorth]

I was going to suggest using a spark tester too. A timing light will also work. I would wire it like this:

 

[rkymtnflyfisher]

Spike Strip has a ballast resistor for sale in the classifieds right now if you need one. OEM.

 

[DustyFJ]

I was going to suggest using a spark tester too. A timing light will also work. I would wire it like this:

View attachment 1109022

I believe this is how it is wired minus the resistor. I was running a 12v (internally resisored?) coil

Is the smart move to buy another coil, or try to pick up a ballast resistor in the classifieds?

(either way I need a new coil right?)

 

[emorth]

Do you have an Ohm meter? If so, what is the resistance (Ohms) between the "+" and "-" terminals on the coil and between the "-" terminal and the high voltage output terminal on the coil?

If you don't have a meter, the $15 to buy one is a good investment.

Let me know what you find.

 

[rkymtnflyfisher]

Any progress on this?