Stumped with running issue

[Wwes]

350 TBI....I've got a problem hope someone can help.

This has happened 3 times..cold start is fine.

Warm engine, shutoff for an hour or two.

Turn key and engine hits like it will start, but stalls. Then just cranks like it has no spark.

I checked spark plug, has spark while cranking on #1.

Watched fuel jet out of injectors while cranking.

Both prior times, when things cooled down it started again. Today, I ran the battery down cranking and no start. This has happened with two separate distributors.

Ideas?

[franken]

Crank w/o touching the gas. Crank w/ the pedal down halfway. Crank w/ the pedal to the floor. Crank while pumping the gas.

[andyh1956]

You need to check your spark, sounds like a classic heat soak coil problem. With the engine hot & not starting, have a helper crank the engine over while you remove the coil wire from the distributor & hold it about 3/8" to 1/2" from a good ground. You should see a good blue spark if it is working properly. If not remove the coil & Ohm it. If it Ohms good then it may be an electronic problem not telling the coil to energize & spark.

[Wwes]

Even more confusion - got it running this AM. Runs ok with timing bypass wire unhooked.

Once hooked back up, doesn't hit or anything.

[andyh1956]

Now this is sounding like an ECM problem. Got a bud w/ a truck like yours you can borrow his ECM & try?

[Wwes]

I think ECM as well. Got a new one on the way, will try it out next week.