Re: Checking coils and wiring

Posted by John T on December 07, 2006 at 08:25:21 from (66.244.90.5):

In Reply to: Checking coils and wiring posted by relane on December 07, 2006 at 06:39:08:

Relane,

QUESTION:

"Hi, How do you check a coil to see if juice is getting to it.............."

ANSWER:

What I do is turn the ignition switch ON (DUH) and then place a test lamp on the coils high input (NOT to distributor) terminal and it ought to glow. Its better to use a voltmeter and then you can really tell more. Unless its a ballast resistor system (12 volt tractor and 6 volt coil) the voltage ought to be near the same voltage as the battery. With the ignition points closed (best way to do these tests) if all is good n wired correct if the voltage on the coils input (NOT to distributor) terminal is like a volt LESS then battery voltage, then I suspect a faulty resistive ignition switch and the spark is gonna be weaker. If the tarctor doesnt spark cuz theres low or no voltage getting to the coils input with th ignition switch ON its easy to simply "Hot Wire" the coils input n see if she sparks then ???

QUESTION

" .......and then going through it."

ANSWER

Place a test lamp over on the coils other low (to distributor) terminal. If juice is getting through the coil (its primary windign is good n continuous) then the lamp should glow ON when the points are open but be OFF when they are closed (where they normally are when setting) What I do is have the test lamp on the coils low (to distributor) terminal n turn her on n crank the engine over (have coil wire removed so she dotn start) and the lamp ought to flash On n OFF as she cranks. If the lamp never turns on, the coils primary is bad/open or the points arent opening or are shorted out but if it never turns off, the points arent good or arent closing or theres a wirign problem

QUESTION

Does the wire from the battery have to go to a regulator and then the coil or can it be bypassed and go directly battery(-) to coil

ANSWER

The ignition feed is usually fed off the ammeters load terminal or the LOAD terminal on a 4 pole Voltage Regulator,,,,,,,,,to the BAT input terminal on an Ignition Switch,,,,,,,,out the ignition switches IGN output terminal,,,,,,,,down to the coil. If the switch or circuit is bad you can "Hot Wire" the coils input from any hot batery voltage source such as the hot ungrounded battery post or the BAT terminal on a VR or Cutout Relay etc.

As far as your light problem, the light switch needs hot batetry voltage on its BAT input terminal which is typically obtained off the ammeters load terminal or the LOAD terminal on a 4 pole VR. Then when on its output terminal feeds the lights. Soooooooo you may not have voltage getting to the switch and you need to check where its coming from (ammeter load terminal or LOAD terminal if you have a 4 pole VR) and make sure its gettign voltage and then if so, the switch and its wiring to lights n lights also gotta be good.

NOWWWWWWW theres also simple tests to see if the coil is firing independant from any distrbutor i.e. see if the coil is good so post back if you need that HOWEVER shes never gonna spark until you get voltage on its input terminal so verify that first then we will troubleshoot the coil further if we need to

Let us know

best wishes n God Bless

John T

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