Not sure how you put the noid light across the coil? Do you mean use test pins in the two wires leading up to the coils connector. Then connect the noid light to those pins? If you watch YouTube some people ground a test light and then connect the other side of the light to the connector pin going to the DG/OR wire.If they crank the engine or jumper the ASD relay contacts the test light comes on steady. They then take a led test light and connect one end to ground and the other end they attach to a paper clip that is inserted to where the gray wire goes to the backside of the coil connector. If the light blinks while cranking everthing is good. Another coil test is to measure the primary and secondary resistances. One ohm on the primary and 15k ohm on the secondary is supposed to be good. A third test is to dissconnect the PCM connector and put 12V on pin 57 and tap pin19 to ground. If a spark is produced the coil is good. This last test seems to be an interesting and quick way to see if the coil is good. What are your thoughts on these different approaches? Also can you use a test light to test the PCM operation without causing damage? Thanks again. Louis

 

You've basically got it; test pins in the two wires (back prod to keep the coil in circuit), and then try to crank and start; it should flash.

The PCM disconnect would also tell you.

OTOH - from the FSM, check the pages I attached.

RwP

 

The primary resistance is 1.2 ohms but there is no measurable resistance on the secondary. I assume its an open circuit. I have ordered a new part but I'm curious if this is a common failure for ignition coils. I thought the more common failure was a short on the secondary which lowers the resistance and also the voltage which produces spark. Any thoughts? Louis.

 

It can fail that way. But where were you measuring to and from for the secondary?

RwP

 

I measured from both pins on the ignition coil connector and the spark tower where the cable from the distributor connects. Louis

 

Next is of course what range were you testing on?

Primary is .95 to 1.20 ohms normally for factory coils; secondary is 11,300 to 15,300. Secondary is normally from the + terminal to the center cap.

If you were set to measure (typically) 20Kohms, and it was open, it's bad, you've found at least part of your problem.

(If you were set to 200 ohms, it'd measure open circuit because, well, 20K is 100x higher than the top end of 200 ohm ... )

RwP

 

Well a new ignition coil did not fix the problem. I disconnected the coils connector and hooked an incandescent test light to the socket hole where the green orange wire goes in. The other side of the light to ground. When i cranked the engine the light lit up so 12V was present. With the coil still disconnected i put a noid light across the two connector holes. But when i cranked the engine the noid light did not illuminate. Question: does the coil have to be connected to its socket for the noid light to illuminate when cranking. Someone on youtube tested for 12V with the coil disconnected but tested for the PCM grounding pulse with the coil connected and the gray wire connection backprobed with a paper clip and then attached to and LED test light. Please advise. Louis

 

Noid light in the connector should work just fine. You should see power for a few seconds at initial key on, and while cranking the engine. PCM controls the ground side of the circuit to fire the coil. (it breaks that side of the circuit to fire the coil.) If the noid light isn't even coming on for a few seconds, or while cranking, then the ground side of that circuit is open, and you need to find out why. Start by testing that wire for continuity between the coil, and PCM.

 

Continuity between pin 19 of the PCM connector and the ignition coil is fine. Also the PCM still generates error codes 12 + 55. So I assume the PCM is working. Could this have something to do with the camshaft or crankcase position sensors? Thanks. Louis

 

the 12 code indicates the battery has been disconnected in the last 50 times the power has gone to the PCM. 55 code is "End of codes" Try saving this link to get definitions of your codes in future
http://www.dakota-truck.net/CODES/codes.html