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Discussion Starter · #1 ·
78 CHEV W 350, intermittant no spark, sometimes jiggling the wires to the distributor will result in it working but now even that is not making a difference.

Any suggesitons, or a test to see where the problem is?

Thanks much!


Ray (truck is Albatross, aptly named)
 

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Get a multi meter and start testing the wires going into the distributer. Check the connectors at the distributer and the connections inside the distributer.
You'll need to trace each wire to its originating point, disconnect both ends and test for continuity. Make sure all grounds are corrosion free.
 

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If you have a "black" distributor rotor, ...it must be thrown out without question!!!
They burn a little hole from the ignition coil pin tab, bypassing the pin burning a micro hole through the distributor rotor grounding to the distributor main shaft where the distributor advance weight are.

Step 1: Test the resistance of the pick up coil. It should be 900 to 1100 ohms steady wiggling the wires around. If the resistance doesn't stay steady, or not in value, just replace the whole distributor assembly, ...just because of the age.

Step 2: If the pickup coil passes, remove the 2 female wire connectors out of the yellow connector with a very small needle or a very small electronic flat blade screw driver to release the retaining tab. Once the female connectors are out, squeeze a little bit down on the connector flaps to make a tighter connection to the ignition module. Also lightly crimp the crimp portion of those connectors to improve electrical contact. Reassemble connectors.

Step3: Remove ignition module, ...throw it away (due to age and the work it had to do over 41 years).
Install a new factory OEM ignition module, ...not an aftermarket!!! Clean "all" silicone residue on the distributor ignition mounting area and the 2 ignition mounting screw threads. If you don't clean those mounting screws properly, you will have phantom crank no fire issues. They are the grounding screws for the ignition module. "Carefully apply" the silicone paste to the new ignition module without touching the grounding screws. Lightly "snug" the 2 grounding screws to the distributor mounting plate. No reefing!!!

Step4: If the distributor cap, spark plug wires, rotor are old, dirty split, oily or original to the motor, replace them also. You know the drill!
 
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