1989 Dynasty 3.0 liter:
For the past year, I experienced a no spark condition when the weather gets cold. ( below 40 degrees guessing). If sunshine, warmth comes alive.
New coil and distributor ( surprise, as original distributor would not release pickup coil Hall effect sensor) done by local mechanic who has always been very good for 20 years.

After vehicle sat all winter with no spark , went back out when 55 degrees and still got no spark.

Test light result : no power to supply side positive terminal of ignition coil from ASD relay. Bad.

I connected jumper from battery (+) to ignition coil positive.
I immediately heard the injectors running nonstop. Q : Is that normal?
Cranked engine.
Result : No spark.
Seems like it should spark when power is fed to (+) ignition coil terminal if grounded and pulsing. Something not right?

I then connected 12v test light between ignition coil negative terminal and the battery (+).
I expected a result of " no test light up" assuming not grounded until it pulses while cranking.
Result : The test light lit brightly nonstop indicating that there was a nonstop constant ground in the ignition coil circuit w/o even cranking.

I cranked engine--> result : the test light went out for 2 seconds , then came on constant bright, nonstop.
Then, burned out test light bulb.

What's going on ?
Plan to get another functional 12v test light and do more testing.

What do these results imply?
I suspect that the constant lit test bulb at negative ignition coil to battery (+) even though it was not cranking is not good.
I expected flashing upon cranking, that did not happen.

Do not yet know if ASD is sending power ( from slave signal terminals ) or even receiving power ( master control switch terminals).
Plan to test ASD later.
In the meantime, bypassing the ASD should have allowed test light flashing if there had been a pulsing / flashing ground circuit; correct?

How to troubleshoot?

 

Tested the power supply to ASD via back probing the ASD heavy green wire with 12 v test light .
It is my understanding that heavy green wire should feed 12v to ASD when I turn key for 2 seconds or when cranking.
Connected 12v test light probe to green wire that feeds power to ASD while the other end of 12v test light connected to battery neg terminal.
Turned key to ON .
Result : No light up of 12v tester, but heard the fuel pump turn on for 2 seconds.
Conclude : no power to ASD during the initial 2 seconds turn to ON . BAD.
Why?

Then , tried cranking with same setup.
Result : still no light up of " test light / ASD green wire " probe.
Conclude: no power to ASD when cranking. BAD.
Why?

Will close this thread and start new thread to address the "no power to ASD".
CORRECTION :
I incorrectly tested the ASD power supply. wiring .
My error was that I incorrectly thought that the heavy green wire at ASD was the 12v supply to the ASD. Wrong.
I now believe that the heavy green wire is the 12v from the ASD to the ignition coil positive.
Upon testing the double white wire at the ASD, it did receive 12v supply to ASD from ignition key.
The ASD also triggered the slave circuit within itself correctly when the control master circuit was energized.
Conclude :
ASD receives power from ignition key switch.
ASD relay is fully functional.
Still mystery as to why the 12v do not reach the positive ignition coil terminal.
New post for that topic.

 

Is that wire controlled by the PCM?

 

RacerHog, I posted a correction to my post before reading your post.
My answer to your question : I believe that the coil negative black wire is grounded intermittently by the PCM.
The green wire receives power from ASD and should feed power to the ignition coil positive. FAILS. why?

I tried to get an exact used replacement PCM ($30 eBay) because I thought that perhaps my PCM had faulty solder joints that expanded/contracted with the weather.
Alas, the replacement PCM had different wiring , tried my best to match part number but failed even tho the eBay ad was marked for my model vehicle.
Will try to pursue mu issue in new posts.

 

For those that do not know what an ASD is:::::: The ASD relay is responsible for supplying switched 12-volt power to the vehicle's injectors and ignition coils, allowing them to provide fuel and produce spark.