83VR, 1 plug not firing, I've tried stuff, but nothing's working, IDEAS?

[Droneh8tr]

So I started my Venture the other day, noticed it didn't sound right or idling quite right. The left rear cylinder wasn't warm. Pulled the plug and thought it was pretty dirty, so I switched it out.. Still no spark.

Primary and secondary coils tested OK

Pickup coils tested OK

Removed/cleaned the plugs to the TCI, NO CHANGE, still no spark

Switched the spark plug boot with another one, NO SPARK

Nipped the ends off the spark plug wire, NO SPARK

 

Shouldn't I be able to read a voltage from the TCI to the coil from the orange and red/white wires? If so, what should it be?

 

Any other ideas?

[MiCarl]

If I recall correctly the red/white will have +12v on it with the key on. The TCI triggers it by interrupting the ground on the orange wire.

 

You should be able to test the coil by putting +12v on the red/white wire and bumping a wire connected to the orange to the (-). You just want to bounce it across, if you keep it energized you can potentially overheat the primary.

 

To a large extent the TCI has four separate circuits in it. Just because it fires 3 of your cylinders does not mean it is good.

[Droneh8tr]

If I recall correctly the red/white will have +12v on it with the key on. The TCI triggers it by interrupting the ground on the orange wire.

 

You should be able to test the coil by putting +12v on the red/white wire and bumping a wire connected to the orange to the (-). You just want to bounce it across, if you keep it energized you can potentially overheat the primary.

 

To a large extent the TCI has four separate circuits in it. Just because it fires 3 of your cylinders does not mean it is good.

Interesting.. I thought their must be a voltage amount going into the coil.. Ill try that tomorrow.

Now, as for the TCI. Can the TCI be repaired? I suspect the answer is no, but, maybe something inside just needs to be unsoldered and a new electrical component installed. Whats your thoughts on this?

[syscrusher]

Diodes can be replaced but must be done before they fail.

With pre-1990 the diodes should be replaced just in case.

I know nothing more about it.

[Droneh8tr]

Diodes can be replaced but must be done before they fail.

With pre-1990 the diodes should be replaced just in case.

I know nothing more about it.

During my extensive tear down, that was one of my projects. So I have done the diodes and a capacitor. Thanks for reminding me about them though.

i think I recall seeing the procedure for testing the TCI. I'll try to find it.