No Spark. MSD? Coil? What did I do?

[rhk109]

While in the process of tuning my Webers I was lifting plug wires off my distributor one at a time to check for cylinder response and after about the 4th or 5th wire the engine died. I put the wire back and and the car wouldn't start. I pulled the coil wire and cranked it, but there was no spark at all. Did I kill (short) something in the process of pulling plug wires? What is the best way to troubleshoot this?

FYI, the car is set up with MSD and Blaster II coil.

[jluetjen]

My understanding is that when you increase the gap you also increase the demands on the MSD box. For example running excessive spark plug gaps can cause premature failure of the MSD box. Removing the wires when the engine was running would have been like intermittentaly increasing the gap beyond spec (prior to the gap being so wide that it was an open). I wonder if you blew out the MSD box. I doubt that you "shorted" it since it wasn't a problem of shorting it to ground. But you might have killed it.

That's my theory. As far as I know the best way to troubleshoot would be to individually troubleshoot the components.

1) Measure the primary and secondary resistance at the coil.
2) Check the resistance of the wires
3) Check the MSD documentation for how to troubleshoot it.

[RoninLB]

did you loosen or gound the dizzy trigger wire between the dizzy and the case?

[kach22i]

Originally posted by rhk109
pulling plug wires?

This is second hand information, but my father-in-law warned me that pulling plug wires off the spark plugs without using a "pull tool" could break the carbon filiments conducting and or isolating the wire. If that happens no-spark gets through.

Perhaps pulling the wires off the distributor could do the same thing on the opposite end.

Can you check the conductivity of the plug wires, or am I missing the point?

[RoninLB]

Originally posted by kach22i

, or am I missing the point?

in his opening post "I put the wire back and and the car wouldn't start" assumed that one damaged plug wire still would allow engine to start. So I also assumed that he did something to stop total ignition or destroyed the coil wire input to the cap. Jluetjen also figured he did something to stop total ignition and gave a good explain on the logic of cause and then on to next step.

and you didn't miss that you can check the condictivity of wires ..even thou the Beru plug connectors can still mislead you into thinking a good routine conductivity wire test confirms that the Beru is ok.

[rhk109]

Sorry for the confusion. The whole ignition appears dead. So I assume it is the MSD box and/or the coil. I'll doublecheck the coil wire tonight.

[rhk109]

Where do I measure the coil resistance and what should it be?

[rhk109]

Primary resistance is 0.9 ohms and secondary is 10.6k ohms.

Both are off from spec of 0.7 and 4.70k ohm but it should still work, right? Probably a good idea to replace it though.

Looking like the MSD box to me. Is there anyway to check it?

[Yellowbird RS]

BLASTER 2
Output Voltage: 45,000 Volts Maximum
Operating Voltage: 12VDC
Primary Resistance: 0.7 Ohms
Secondary Resistance: 4.7K Ohms

You can call MSD TECH LINE: 915.855.7123
If it is possible can you send the unit in for review? There is repair charge, which runs from $15 to $85 plus shipping. I will also supply you with an address to ship the unit to.


Customer Service Department
Autotronic Controls Corporation
12120 Esther Lama, Suite 114
El Paso, Texas 79936

[Yellowbird RS]

[Yellowbird RS]

The following test will determine if your MSD is producing a spark.

White Wire Trigger:

If you are using the White wire (points or electronic amplifier) of the MSD to trigger the ignition, follow these steps.

1. Make sure the ignition switch is in the Off position.

2. Remove the coil wire from the distributor cap and position the terminal so it is approximately 1/2" from a good ground.

3. Disconnect the MSD White wire from the distributor points or the ignition amplifier.

4. Turn the ignition to the On position. DO NOT CRANK THE ENGINE.

5. Tap the White wire to ground several times. Each time the wire is pulled away from ground a spark should jump from the coil wire to ground. If spark is present, the ignition is working properly.

If there is no spark:

A. Inspect all of the wiring.

B. Substitute another coil and test again. If there is now spark, the coil is at fault.

C. If there is still no spark, check to make sure there is 12 volts on the small Red wire from the MSD when the key is in the On position. If 12 volts are not present, find another 12 volt source and repeat the test.

D. After inspecting the test procedures and inspecting all of the wiring, there is still no spark, the Ignition is at fault.

Magnetic Pickup Trigger:

If you are using the 2-Pin Magnetic Pickup of the MSD to trigger the ignition, follow these steps.

1. Make sure the ignition switch is in the Off position.

2. Remove the coil wire from the distributor cap and position the terminal so it is approximately 1/2" from a good ground.

3. Disconnect the MSD Magnetic Pickup connector from the distributor.

4. Turn the ignition to the On position. DO NOT CRANK THE ENGINE.

5. With a small jumper wire, short the Green and Violet magnetic pickup wires together then pull the jumper off. Each time the short is removed a spark should jump If spark is present, the ignition is working properly.

If there is no spark:

A. Inspect all of the wiring.

B. Substitute another coil and test again. If there is now spark, the coil is at fault.

C. If there is still no spark, check to make sure there is 12 volts on the small Red wire from the MSD when the key is in the On position. If 12 volts are not present, find another 12 volt source and repeat the test.

D. After inspecting the test procedures and inspecting all of the wiring, there is still no spark, the Ignition is at fault

[rhk109]

Thanks Yellowbird.

I'll try it tonight or tomorrow. Luckily, I am planning on attending the NHRA event at Maplegrove this weekend. MSD tech support told me that they would have a truck their to test my components if needed. They also will be able to sell me new parts if needed.

[rhk109]

Update:

MSD tested my box at Maplegrove and it was shot. Bought and installed a new 6A and blaster 2 coil and it fired right up.