Great HEI tech/troubleshooting article

[shiner2001]

This was posted on one of my Jeep forums in response to some HEI gremlins I am chasing right now. Just wanted to share it here as well...

http://www.chevelles.com/techref/ftecref5.html

[cpetersen]

Great article.

[LostMy65]

Googled 'HEI Troubleshooting' and this thread popped up.

Thanks

[LostMy65]

Here's a good rebuild article:
http://www.rustpuppy.org/ignition2/Ignition%202b.htm

[RCbowtie69]

cool

[LostMy65]

I found some more good info:

Originally Posted by alant470

The easiest way to test a module on the car is to ensure that the wiring & pickup coil are OK. The module is essentially an amplifier with a built in analog to digital convertor.



Easy tests for HEI system:

1. Test for power at the pink BAT terminal. You should have battery voltage w/ the key in the start and RUN positions.

2. Connect the ground side of your test lamp to the battery POSITIVE cable. Probe the TACH terminal on the dist. cap while a helper attempts to start the engine. The test lamp should blink repeatedly as the engine cranks. No blink= bad module or pickup coil. Further testing is required to pinpoint the problem. Blink but no spark = bad ignition coil.

3. Remove the cap & rotor. Remove the green & white leads from the module. Connect your ohmmeter to the green & white leads. You should have approx. 800-1500 ohms depending on the ambient temperature. Open circuit (infinite ohms) = bad pickup coil.

Wiggle the green & white leads as you test. Ohm reading should remain constant if the leads are good. If the reading varies as the leads are wiggled, the pickup coil is bad. You'll often find broken pickup coil leads this way.

4. DVOM (meter) still connected to green & white leads. Set your DVOM to AC VOLTS. Have a helper crank the engine as you watch the AC VOLTS reading. A good pickup coil will produce about 3V AC when cranking. Less than approx. 2V AC indicates a bad pickup coil.