distributor hot/no spark

[agr8n8]

I have an 83 305 C10, H-type that was a 'basket'. I rebuilt the engine and installed it (no tranny installed yet) and want to make sure it works before investing any more. The distributor gets hot when I turn on the ignition and, of course, no spark - I assume these are related.

I have replaced the ignition coil even though it Ohmed Ok and the ignition module. The pickup coil reads OK (1000 ohms). New cap and rotor with the build. It would seem I have some kind of short - or hopefully I'm overlooking something simple. I am officially out of my league - help!

[mbumgua]

Did you run a new hot wire to the dist? If yes make sure it is hot with the ign switch turned to start as well as hot on run position. New Distributer or old? HEI? Check ground stap from coil.

[mbumgua]

Ground Strap

[agr8n8]

No, using existing wiring. Original HEI distributor - with new coil, ignition module, cap and rotor - had same results with old ones before replacing though. coil is grounded, but I don't have a wire that goes into the tach slot - I assume because I don't have a tach, but would anything else plug in there?

[hotrod_chevyz]

Double check and make sure the distributor cap is assembled properly.

[etuke]

just a thought but have you checked to make sure the distrubitor is actually turning while cranking?

[777stickman]

but I don't have a wire that goes into the tach slot - I assume because I don't have a tach, but would anything else plug in there? That's what it's for, just a tach connection and nothing else. Since you had this problem with the same dist before and the wiring hasn't changed, I would seriously consider replacing it with one known to work.

[mbumgua]

Did you change the pickup coil in the dist?

[hotrod_chevyz]

Originally Posted by agr8n8

The distributor gets hot when I turn on the ignition and, of course, no spark - I assume these are related.

...Explain "hot". Do you mean its getting power, or that something is actually getting hot as in, the stuff that cooks a steak?

[GMMerlin]

Originally Posted by hotrod_chevyz

...Explain "hot". Do you mean its getting power, or that something is actually getting hot as in, the stuff that cooks a steak?

That is what I am wondering.
How did you check for power at the dist...test light, DVOM?

Is the little black button from the coil making contact with the rotor.
Is the ground strap installed

[hotrod_chevyz]

Originally Posted by GMMerlin

That is what I am wondering.
How did you check for power at the dist...test light, DVOM?

Is the little black button from the coil making contact with the rotor.
Is the ground strap installed

Exactly what i was wondering. If he installed the button AFTER he installed the rubber piece in the cap it will never work. Ive seen that happen so many times.

[agr8n8]

The distributor is physically getting hot, like there is a short. My button, cap, rotor are all correctly assembled. It does not get hot when I unplug the 4 pin connector going to the ECM. I checked power with a test light and an analog meter - all good.

I pulled the ECM from under the dash and the coating is all bubbly looking, like some kind of corrosion. I think the ECM may have some kind of short causing the problem. My Dad got hold of a chilton book that says I can bypass the ECM by jumping the pins on the 4 pin connector. We are going to try that tonight and i am reasonably sure we will be able to trace the problem back to the ECM or the wiring for the ECM. I will report back and let you know. Thanks for all the suggestions.

[agr8n8]

Bypassed the ECM and got spark. Started and ran the motor for a few minutes for leak checks, timing, etc. then inspected the wiring harness to the ECM and checked for shorts/opens - all good. Put the old ignition control module in so I could verify the ECM problem one last time before spending $125 for new and tested before hooking up ECM - still good. Connected ECM expecting ditstributor to get hot, but OK.

Tried starting and it works like a charm. something was funky somewhere, but I either never found the real problem or the ECM was stuck in a bad state somehow. Lesson - no matter how improbable, check it anyhow and check it twice, one step at a time.

**One note** for anyone bypassing the ECM with the jumper - my chilton manual said to jump pins A and C on the distributor connector, but after no spark and tracing the wires, that config is grounding the pickup coil. Jumping the alternate pins B and D worked and actually correspond to the A and C pins on the pickup coil connector - hope that helps.

[hotrod_chevyz]

Thats cool you figured out the problem. Since its the computer, why not just bypass it by getting a older style HEI distributor? those work with a single 12 volt source, and a hose, rather than a bunch of sensors and crap. You can pick up a rebuildable one WAY cheaper than replacing the computer, and later on you will not have to worry about any old sensors or other old computer controlled stuff.