1990 Other Chevrolet Models Engine cranks but will not start

I have seen ignition modules defective out of the box, you might want to check that. It sounds like you went through all the rite steps to find the problem. Exactly what kind of car is it?

This is a 1990 Chevy Half-Ton I am Working on. I bought a distributor with everything on it, and I also swapped the HEI Module out with my other truck which is a 1990 GMC 1/2 Ton. That truck still runs.

I had a problem like this with 1 of my chevys, it turned out to be my tachometer in the dash, it shorted out somehow. If you have a tach try unpluging the tach wire from the dist.

No I don't have a tachometer. But another thing I tried was swapping out my ECM with my other truck. Still No Spark. I took my Ignition Coil from both trucks down to the auto parts store and had them tested and both were fine just like I thought. I have done every test, I have replaced every ignition component, even my ECM.
How is this possible that I still don't have spark. It seems like nobody knows what my problem is and they don't know where else to look. I guess I'm going to have to take it in to the shop.

My Ignition Coil has two connectors with two wires each. One of the wires is a Red Wire which is my power lead the other one is a white wire has to be the one that sends a signal to tell the coil to fire. I would think you would want to check that wire for a signal, but there seems to be no test that checks for that. Does anybody know how to check the White Wire for a proper signal.

A test light or an ohmeter should be able to test the white wire for signal, It is probably a ground that sends the signal. Do you have power to the positive side?

I have power to my postive side of both connectors. I put a test light on the white wire coming from the distributor. With my key forward but not in the start position the light is on, when the engine is cranking the light is on but flickers with the cranking of the engine. The light never goes out. This is the same with the white wire on the other connector. I have been talking with another person who told me to do this test and they said the test light should pulse. My light doesn't pulse since it never goes out right? I haven't got back with this person yet to see what the next step is, do you know? Thanks for the help so far.

You have to remember the power pulses so fast that the test light might not have enough time to turn completely off before it goes back on. You have already done about everything I can think of. Did you take they dist cap off and make sure the dist is spining. You said you replaced it, did you get it all of the way in and lined up correctly? Where are you losing power? Does it have spark from the coil at all, or does the spark stop someware else? Check the most obvious things 1st, we all tend to over look the simple things. If I can think of anything else I will let you know. Keep me posted and your votes and feedback are appreciated.

Before I took my old distributor out I marked on the firewall in line with the groove on the shaft and I marked where it mounts to the engine. When I got to the store I took a measurement from the mark on the mount to the cast/mold mark on the mount and transfered my measurement to the new one. When I put the new distributor in, the groove in the shaft didn't want to line up with my mark on the firewall. It seemed like it would've lined up right but it wouldn't drop all the way down. So I tried rocking the truck hoping it would drop in but it didn't. So I tried the next tooth and it dropped but it didn't line up and I kept going all the way around. It dropped on that one tooth and 180 degrees in the other direction, so I put it back to the first one. I didn't think it would matter anyway because I should have spark on any tooth right? So I put everything back together and still no spark. The distributor is spinning to answer your question. And I don't have spark at my coil, my coil is where I have been testing all along.

I forgot to mention that I tested my red and white wires coming from my distributor to my coil. I had no power with the key forward and while cranking. The larger red wire that goes to the other terminal had 12-volts with the key forward and wile cranking. The white wire had 12-volts with key forward but 0.5-volts while cranking. This doesn't sound right is this my problem?

Yes you should have spark on any tooth of the dist. As long as you have the cam gear and the oil pump shaft lined up it will drop in. You already had the coil tested so thats not it. Have you checked for bad connections, damaged wiring, fusible links, and all connections are in the correct spot? Im sure you have but you have me stumped on this one and I cant think of anything else it could be. I bet it is something simple. It would be nice if I could look at the truck myself. Make sure you have good ground wires hooked up and free of rust and corrosion. And check your battery cables and cable ends.