Have the coil checked as well.

i know when i instaled my tac it did the same think i do not have an hei but i had the wires switched on the coil

Have you unhooked the tach and tried it?

unless im missing what your saying, that is the coil

First, check that you have 12 volts at the coil during startup. Not just in the on position. Then make sure that all the wiring to the coil is hooked to the correct connections ( the coil will not work with the wires in the reverse positions.) If these items are good then disconnect the ground wire from the coil and check for 0 or close to 0 ohms from the end of the wire you disconnected to the engine block. If all these are good then remove all the ignition components and take them to an autoparts store or mechanic to have them tested. Hope this helps a little.

I replaced the module under the rotor and still no luck. I will replace the cap and rotor, just to make sure that is not it. After that, I am not sure which way I will go.

Thanks

Ron

If it were me in your shoes after all you've done so far I would first run a jumper wire from the batt terminal to the battery and try to start her. Then, if it doesn't start, I would pull out a spark plug, plug the wire back on it, ground it( I use a jumper cableon the neg batt terminal on one end and grab the spark plug body on the other end, makes it easier to do by yourself) try to start it and check for sparks. If no sparks, you have eliminated the wiring to the dist. Then I would pull the cap and check the dist wiring, make sure the ground strap was in there, check the module. While you are in there you might spin the engine and make sure the rotor turns, etc.
Also, since you say you installed a tach, you might uninstall it and try the engine then.
Good luck.

Also take off the cap and turn the engine over to see if the rotor is turning. You might have sheared the pin in the shaft.

Ok, lets see.

Rotor turns, not sheared. Noticed that when I got it TDC

Replaced the coil (under the cap)

Replaced the module. (Banana shaped thing)

Pull dizzy and took it apart & replaced the thing around the shaft.

Still will not start.

Still no spark to the plugs.

Lost now!

Thanks

Ron

so this truck was running, you parked it, installed a tach, now it wont start? youve replaced alot of stuff and still wont start!!, id go "double" check that every thing is hooked up correctly. heres a diagrahm and a link http://67-72chevytrucks.com/vboard/s...threadid=13698 jeff

Hey Jeff,

I have done that several times. I cannot get passed the fact of power to the dizzy, but not after. What would cause no spark? I have not replaced the cap & rotor yet, because they are still fairly new. Have hardly any marks on them.

Before I parked it, I was having trouble starting then to, but it started. If it was running, then it would be real hard to restart.

WHen that happened, I replaced the fuel filter.

So, I have no spark after the dizzy. I will replace the cap & rotor to see if that does it, but if it does not, then what else would there be?

Thanks

Ron

When all else seams to fail start at the beginning to resolve problem.
1. Check the Ditributer Rotor, GM rotors were notorious for burning a hole through the rotor, you will have to pull off and look underneath of it, if you see a black burnt spot, this will do it..I have seen new rotors burn through in what seems likee no time at all.
2. Make sure you have voltage to Distributer and disconnect Tach to eliminate possible issue,
3. You replaced coil (new Coil?) under the HEI cap, which there should also be a ground under the coil,
4. Check cap to make sure the center elctrode is there, you should have gotten new one with coil and replaced as well.
5. check when you are cranking engine the 12 volt lead to distributer has voltage while cranking.
6. The plugin from distributer to cap is also plugged in.
7. DOuble check grounds, run jumper cable from frame to engine and Negative battery terminal to frame.
7. If still no spark. You have a serous problem.

:bowtie:

I have the same problem on a SWB in my yard. It ran but poorly so I tried to move it and it just wouldn't start anymore. I cranked and cranked, checked gas -OK, changed module----no spark to plugs but 12V to the dist.'
I think it is the little condenser in the distributor. I had a similar problem 2 years ago and it drove me nuts. It's cheep, easy to change and often overlooked. worth a shot---.
good luck

What does the condenser look like? Is it the round tube looking thing?

Thanks

Ron

Right--it has nothing to do with running on a HEI-it is there for noise filter for radio. Of course if it is grounded out inside it will kill your spark. Just disconnect it and see if it will start. (condenser has a purpose on a points ingnition)

Since it sounds as if the HEI was previously installed, how did it run before? It sounds like a ground issue or voltage to the HEI itself is a problem.

When you say you have voltage @ the distributor but not after, exactly how much voltage do you have (for sure)? Run a hot wire (10guage) from an ign-unfused source on the fuse-block directly to the batt terminal on the distributor & see what happens. If the rotor is turning (no broken timing chain) you should have spark. No spark, look @ the coil & it's ground strap.

Keep us posted. We all love a good mystery......we just hate it when it happens to one of us & in this way! :banghead:

i personally at this point replace the distubutator and see what happens

..
 

You said it's been sitting for a while. Make sure your tires are at the correct air pressure, and that your radiator is topped off....j/k



assuming you have power to the distributor, and assuming you confirmed that it's the spark that's absent and not fuel or a broken timing chain, there are three things it could be. Listed in the order of failure in my experience (1)the pickup coil, (2) the modual, (3) ignition coil

pickup
 

pickup coil image

you said that you ckecked for spark against the inner fender and i am not 100% sure on this but maybe it won't ark through the paint or will it. That is just my $0.02. I am probably wrong but what the heck it never hurts to speak your opinion does it?

Did you do any ignition switch work? I had a similar problem after I rehooked up my ignition switch. The dizzy would get power in the on position, but when put in the sart position would not get power. I had 2 wires backwards on the ignition switch. One wire interrupts power when cranking(start position)so to give all the power to the starter (ie radio, A.C., etc), When put in run position it gets power again. The other wire gets power all the time when ignition turned to start or run. These 2 wires were backwards, so I switched and then it worked fine. Maybe your ignition switch went bad? Hope this helps a little. Good luck!
Shawn

Found my problem on my SWB this afternoon. Forgot to put the two screws back in the Module that mount it to the Dist top plate. After I did that, the bugger kicked off fine. Now how I forgot them little screws---well let's just say "Brain Fart!" Da!!! :D

glad to hear you found it. been waiting for that post. I hate it when it's my fault! :banghead:

Check the pickup coil (white donut shape with two wires coming out of it-you must remove the dist shaft from the dist housing to replace the coil) as suggested above. Had one that after a few years one of the wires broke due to fatigue and constant movement from the vacuum advance. And yes, the 12v supply to the dist should be there during cranking and while running. Means the latest thing you have done is add the tach, unhook the tach wire from the dist and see if any symptoms change. I would also leave it unhooked until the vehicle is running again. Once it runs, then hook the tach wire back up.

Randy

Started to write my suggestions, got interuppted, finished writing and posted. :rolleyes: There has been about 6 posts since I started the post. Glad to hear you got it running.

Randy