Post by Pontiac1976 on Feb 15, 2016 11:08:03 GMT -5
HEI PLUG WIRE
RESISTANCE CHART
[_wire length ________ minimum_________ maximum_]
0-15 inches 3000 ohms 10,000 ohms
15-25 inches 4000 ohms 15,000 ohms
25-35 inches 6000 ohms 20,000 ohms
Over 35 inches 25,000 ohms
~Un-plug wiring connector from the cap.
~Turn four Latches using a Screwdriver & remove Cap & Coil assembly from lower housing.
~Connect an Ohmmeter between distributor cap terminals ‘TACH” & “BAT” to test the ignition coil’s primary coil.
The primary coil resistance should be less than 1.0 ohm (zero or nearly zero).
~Make the following ohmmeter measurement using a high resistance scale:
a. Connect an ohmmeter between the carbon button in the cap & the “GRD” terminal on the distributor cap
To test the ignition coil’s secondary coil. Record your’ reading.
b. Connect an ohmmeter between the carbon button in the cap and the “BAT” terminal on the distributor cap to
test for short in the ignition coil. Record your reading.
c. If infinite ohms or resistance was measured in both measurements, the ignition coil is defective & needs to be replaced.
~If the ignition coil test ok, it’s a good idea to test the pickup coil.
These resistance checks will not disclose shorted coil windings.
This condition can be detected only with scope analysis or suitably
Coil with a known goon coil as a final coil test.
Test the Pickup Coil
~To test the pick-up coil, first disconnect the white & green module leads.
Set the ohmmeter on the high scale & connect it between a ground & either the white or
Green lead. Any resistance measurement less than infinity requires replacement of the pickup coil.
~ Pick-up coil continuity is tested by connecting the ohmmeter (on low range)
Between the white & green leads. Normal resistance is between 500 & 1500 ohms. Move the vacuum advance arm while performing this test.
This will detect any break in coli continuity. Such a condition can cause intermittent misfiring. Replace the pick-up coil if the reading is outside
the specified limits.
~if no defects have been found at this time, & you still have a problem, then the module will have to be checked. If you do not have access
To a module tester, the only possible alternative is a substitution test. If the module fails the substitution test, replace it.
The ignition module can only be tested using an ignition module tester. Since these testers are not readily available to the average do-it yourselfer, if
you suspect that the ignition module is bad, it’s a good idea to check all the other components of the HEI system before replacing the module. Pay
particular attention to all the wiring connections , since many times these connections vibrate loose or corrode. What
looks like a good connection may not be, so be sure to clean all connections & disconnect all connections.
This was asked about a few times now. So I am putting this up here now. I hope this helps out others that may need this too.