I have a 79 351m. It cranks over good and there is fuel in the carb (when i manualy move the throtle i can see fuel come in). So i tried putting a screwdriver in the coil wire and holding it near the post on the distributer. when i cranked it there was no spark. does this mean that I am not getting spark or does that only work on lawnmwers and smaller engines? And if i am not getting spark what would i have to replace all wires are conected near the coil.
Thanks Dan

 

The screwdriver method you describe isn't a bad idea, but there are better ways to go about it. Take a plug wire and hold it near something grounded - the block, etc. Have someone crank it over. You should see a strong spark going from the end of the wire to the ground. If not, then you have a problem somewhere. You might want to start with the coil. Most parts stores can test them.

 

At the ignition module on driver side fender wall. There will be a red wire and a white wire.

Test for the ignition module, test of the red wire and a white wire at the harness to this ignition module. Verify the red wire has positive "+" power with the key in the on position. And then verify the the white wire has positive "+" power with the key in the start position.

If this test of wires has positive power. Then check for positive power at the COIL on the engine with the key in the on position. If positive power is not present then replace the ignition module.

Another check is to verify the contact on the wires to the coil. Check for any breaks in the wiring.

 

thanks the coil doesnt have to be in the vehicle to have the auto place check it right?
Thanks Dan

 

Nope, they can power it up and tell you if the output voltage is within range to run the truck with it sitting on their test bench.