7AL3/HVCII/ProBillet - 468 Chevrolet

[oldsman]

System has developed a miss that seems to increase with run time until
car will not start and there is no spark from coil.

It's a 468 Chevrolet @ 13:1 spraying NOX. Condition just developed.

Pro Street / Strip car. Wires are new, new plugs, timed perfectly.

Purged fuel system, new filter, fresh VP 116 race fuel installed.

Seems like it's heat buildup related - worsening as things heat up.

Where do I start troubleshooting?

I have a spare HVCII coil and can borrow another Pro-Billet distributor.

7AL3 would be a bear to change as it's buried under the dash. How do
I troubleshoot it?

All three components are brand new with less than three hours run time.

[msdtech1]

To start I would run the vehicle until you get the condition where the engine no longer starts and then perform the follow test. You need to do these tests right after the unit quits on you.

First, with an ohm meter check the resistance across the distributors magnetic pickup wires (Black/Orange and Black/Violet). The resistance should read between 400-1300 ohms.

Next, perform a spark test on the ignition as follows below. The following test will determine if your MSD is producing a spark.

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. See the Warranty and Service Page for Information.

MSD Tech1