No spark

[Tkdb]

Hello all. I've got a '74 c10 with a 350 that I just finished a little freshening up on. I reinstalled the distributor and ran a new key-on 12v wire to the coil and a new ground for the distributor. The distributor is an MSD model#8360. Everything is wired in accordance with the diagram provided by msd. I have power at the +terminal of the coil with key on and I have verified it has a good ground. I've also verified the rotor is spinning while cranking. However I have no spark at the plugs and no spark from the coil to the distributor. How and what do I start checking next to start the process of elimination? Any help is much appreciated, I've got little experience with ignition components and am out of ideas. Thank you very much in advance!

[Henry]

Hi Tkdb:
Sounds as if your coil is weak...do you have a 110V test light to check for open and grounded circuits? If not, call a car parts place and see if they can test if for you. Do you know the checks to make with a test light?
Regards,
Henry

[VileZambonie]

Where did you install your coil + from? Make sure it's a full 12v source with key on AND during crank. Don't use the resistance wire.

[Tkdb]

Hi Tkdb:
Sounds as if your coil is weak...do you have a 110V test light to check for open and grounded circuits? If not, call a car parts place and see if they can test if for you. Do you know the checks to make with a test light?
Regards,
Henry

The only test I knew how to do was to hold the test light on the negative pole, and during cranking it should flash. Which it did. This was done with just a 12v test light. The coil however is a new MSD Blaster2.

[Tkdb]

Where did you install your coil + from? Make sure it's a full 12v source with key on AND during crank. Don't use the resistance wire.

I got the key on +12v from the spade on the front of the fuseblock labeled "Ignition" The +pole on the coil stays hot during cranking according to a test light. I will pick up a multimeter on my way home tonight and check it for an actual 12v.

[Rapid Roy]

What gauge 12v wire did you use. Some I have seen recommend 14 gauge or larger. If it is 16 gauge, may not be supplying efficient voltage. Just a thought.

[Tkdb]

What gauge 12v wire did you use. Some I have seen recommend 14 gauge or larger. If it is 16 gauge, may not be supplying efficient voltage. Just a thought.

I used a 12ga wire for the coil+ feed.

[bd]

So, distributor red to coil positive, distributor orange to coil negative, and distributor black to ground.  Is the gray wire connected? 

Clip your test light to a "verified" good ground (such as the battery negative post) then probe the distributor's black ground wire and crank the engine.  If the test light flashes, even dimly, make sure the black wire is making a suitable connection with its terminal and the terminal is solidly connected to a shiny bare ground.  Otherwise, run a temporary jumper between the black wire and the battery negative post, then retest.  If the test light doesn't flash, substitute a different ignition coil and recheck for starting.

BTW, the I+ tap you used on the fuse box is protected by the 10-amp backup lamps fuse.

[Tkdb]

So, distributor red to coil positive, distributor orange to coil negative, and distributor black to ground.  Is the gray wire connected? 

Clip your test light to a "verified" good ground (such as the battery negative post) then probe the distributor's black ground wire and crank the engine.  If the test light flashes, even dimly, make sure the black wire is making a suitable connection with its terminal and the terminal is solidly connected to a shiny bare ground.  Otherwise, run a temporary jumper between the black wire and the battery negative post, then retest.  If the test light doesn't flash, substitute a different ignition coil and recheck for starting.

BTW, the I+ tap you used on the fuse box is protected by the 10-amp backup lamps fuse.

Gray wire is not attached currently. I'll try these. Thanks.

[Henry]

Hi Tkdb:
Since your coil and distributor are new, they are most likely not the problem then. If all other electrical checks others have been suggesting check out, another simple test is for the integrity of the high tension lead that goes from the coil to the distributor...is it in good shape? A simple test is to plug one end into the coil and hold the other end(hold at the insulation, not the actual contact) with some good insulated pliers close to the block and have someone crank the engine...you should get a good strong spark...if not, there is something wrong with the cable or the crimped contacts at the ends of the cable.
Regards,
Henry