350 chevy truck cranks but won't start

Truck ran fine with no indication of problem. When outside temp. dropped in teens one morning it wouldn’t start. Would crank normally but not start. Found no spark. Replace HEI distributor and no start. Have replaced spark plugs, had starter and battery tested. All are good. Edelbrock 600cfm carb is 6 months old. Truck was completely restored 20000 miles ago so mechanically it’s a new truck. I have no idea why it won’t crank.

Are you getting 12V to and from the coil?

I change the coil if I have a GM engine that won’t start in the cold and has no spark. It’s cheap and I worry about the other stuff later. If you put another used distributor on it, I would take it inside and change all the electronics in it.

Check the rotor for damage and make sure the center electrode in the distributor cap is intact.

there is 13V to the coil with the ignition on. I put a new distributor in because I was not getting a spark. I have a spark now. Carburetor is functioning normally.

Divide and conquer! Spray some starting fluid into the carb throat and try starting the engine. If it sputters or starts and runs for a brief period, you have a fuel issue. Eliminates guesswork. If not, continue diagnosing by checking spark and compression.

It’s a long shot, but have you checked the ballast resistor?

Ed B.

thanks. Tried the starting fluid already. The engine doesn’t even try to fire. I’m really stymied on this one. The engine has only 20,000 miles (the entire truck was restored 2 years ago). It’s been well maintained. I took the starter out and had it tested and it passes the tests, but those test machines don’t put it under a simulated load - just spins it. I went ahead and ordered a new starter so I’ll give that a try when it comes in. If that’s not it, I’ll have a spare starter for when it does go out.

Not sure what the ballast resistor is. Is this something in the original OE distributor? I have a HEI distributor. It was not sparking. Installed new dist. and now have spark but no start.

Did you line the dist up properly? It is easy to get it 180 degrees out, If you line it up with the rotor pointing to #1 at top of the exh stroke, and not the comp stroke.

OK, good.
Next question, is the starter motor turning the engine over at the normal speed? This is something you can tell by listening. If it’s extremely slow or fast, that would be something to be concerned about. Too slow is either a starter motor problem or a electrical supply issue. Too fast can indicate a broken timing chain for example. Not sure why you changed the starter motor unless it was turning the engine over too slowly. If it cranks normally, it’s not the starter motor…

How did you verify spark?