Troubleshooting 73 Dart Slant 6 not starting.

[lsrguy2007]

I bought a chassis manual but still can't figure it out. I don't get any spark at the plugs or out of the coil. Both of the small terminals at the coil measure +12 Volts when the ignition is in both position 1 or position 2 (engine cranking). Is one of the coil terminals supposed to go to ground through the Electronic Ignition Module when in position 2? Any help would be appreciated.















volt

 

[67Dart273]

The electronic box is a switch that replaces the points. Anytime the key is in "run" and a working system gets power, the coil draws current as if the points were closed. When the distributor triggers the box, it turns off the coil for a short length of time, and this is what forms the spark.

Turn key to "run." Measure voltage from coil + to ground. It should NOT be full battery voltage, but, rather, about 5--8 or maybe 10V

If coil is at full battery voltage with key in "run" this indicates either the coil is bad (open), a wiring error or problem, bad connection at the ECU connector, or that the ECU is not grounded, or that the ECU is bad

Turn key to "start" while watching meter. Coil + should be close to battery voltage.

Separate distributor pickup connector. Take the end to the harness, not the distributor. Tap the bare terminal on ground, while having a spark gap rigged to coil +, and with key in "run." Each "tap" should make a nice snap single spark. use something else for a wire out of the coil tower instead of the coil wire, as it may be bad, as well

 

[lsrguy2007]

The electronic box is a switch that replaces the points. Anytime the key is in "run" and a working system gets power, the coil draws current as if the points were closed. When the distributor triggers the box, it turns off the coil for a short length of time, and this is what forms the spark.

Turn key to "run." Measure voltage from coil + to ground. It should NOT be full battery voltage, but, rather, about 5--8 or maybe 10V

If coil is at full battery voltage with key in "run" this indicates either the coil is bad (open), a wiring error or problem, bad connection at the ECU connector, or that the ECU is not grounded, or that the ECU is bad

Turn key to "start" while watching meter. Coil + should be close to battery voltage.

Separate distributor pickup connector. Take the end to the harness, not the distributor. Tap the bare terminal on ground, while having a spark gap rigged to coil +, and with key in "run." Each "tap" should make a nice snap single spark. use something else for a wire out of the coil tower instead of the coil wire, as it may be bad, as well

Thanks for the information. I measured +12 Volts from both the + and - coil terminals to ground when the ignition key was in the "on" and "run" positions. I'll run the tests you mentioned. Thanks again.

 

[AJ/FormS]

A quick test is this;
I call it the one-spark test.
1) Near Ground the coil tower, and cycle the key off/on/off.
Every time the key is turned off, you should get exactly one spark. If you don't get it,
2) First check the power supply line, from the ballast resistor for power, and
3) then the case ground back to the battery. If both are good,
4) sub in a different known to be working, ECU, and try again. For this test, You can sub in, ANY Ecu, regardless of application.
5) if you do get the one-spark, but no trail of sparks on cranking, then
Pop the cap and make sure the distributor driveshaft/reluctor is rotating during cranking,
6) that the reluctor gap is anything less than 020. If that is Ok, then
7) check the pick-up for continuity. IDK the spec, but I do know they work just fine at between 160 to 320 ohms, at summer temps, lol..
8) open circuit makes it junk.

If you suspect the coil, again near ground the tower, Run power to the + side and install one end of a long jumper onto the other terminal, all by itself. Then, watching the gap, swipe the other end of the wire on any good ground, looking for a spark. This will only work if you can make and break the ground connection very rapidly. So it may require a little learning curve.
I drag the jumper-wire over an old file, laying on a grounded surface, and watch the lightning show.. You can't hurt the coil during this procedure , so have at it.

 

[lsrguy2007]

Hi. I didn't get any sparks out of the coil. I traced the wire from the - side of the coil to the ignition control module with my ohm meter and it Read 0 ohms. I then placed my voltage meter on AC and monitored it to ground while cranking the engine. The meter read erratic voltages which told me that the ICM was pulling the - terminal from the coil to ground but there was no high voltage coming out of the secondary of the coil. This told me that the coil was bad and it was. Cheap fix. I went ahead and replaced the coil and it fired up. I ordered an ICM and a ballast resistor module just to have them. Thanks for everyone's advice.