'79 k5 blazer- i have replaced the coil and the ignition modual had it running the other day and then let sit for a couple of hours and im right back where i started it turns over but will not start i am nt getting any spark what else could it be other than what i already replaced. And i am getting fuel

 

When you worked on it you would have moved wires and stuff around. Is it at all possible that the trouble you fixed is not the trouble you had?...

I've done silly things like have the wire to cap from the ignition fall right off. A 79 is HEI with plug at the cap. Two wires. One for tach one for ignition.. Is the ignition one getting 12 volts? I had a 78 truck that it used to just fall out off when the terminal would get weak. The plug had broken and I had used a push on spade terminal crimped to the wire.

Sometimes I would shove it up there and actually miss the terminal while still belieing I had it on there. The wire would sit there and look real good??? If you dont get 12 volts from your ignition switch,, or only get it once in a while, this could be bypassed with a direct wire, but you would have to pull it off to shut off the engine. Of course If you dont get 12 volts from the ignition switch, then the path TO the ignition switch may be open. The switch doesnt have to be bad, but often is.

My 68 is actually that way right now. Will fix.

This has a fuse and also a link. About where I started from. Nothing else to cover here.

The inside the cap wiring might also have a problem. I've had to replace a few of those small harnesses in there with the module. Did you change the capacitor also? Its not hard to take the module back out and check it. I used to have a haynes with the testing procedure in it. Takes an ohmeter, I believe. If not, you can have it checked at the parts store. Having a good capacitor is a need if modules are giving you trouble.

If modules are blowing out, do you have any alternator problems?

 

ok first i put in a new ign. mod. and a new capacitor and it started right up.Then i turned it off and it went right back to doin the same thing so i took my alt. off and the ign. mod. and took them down and had them tested both good.I also picked up a new cap and rotor bug aswell so now im going to go put all it all back together and ill let u know.

 

Have you checked for the positive voltage at the cap terminal to the coil? Have you checked the coil INSTALL itself? Sometimes something goes astray with the way the new coil went in and problems happen.

I have had a problem with ground at some time or another. One time I was lazy and left the distributor a little loose, I created a problem. Ground comes through the body of the distributor and if its loose and greasy or oily, it may not get a good ground .