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Ok I had 12.43 at the battery and 12.26 at the wire that goes to battery side of the cap.
Did you disconnect the wire to the BAT terminal on the cap when the above results were observed?
If so, your HEI is wired correctly (as long as the gauge of the hot wire is adequately sized).

I took the top of the cap to expose the coil. I checked voltage on the coil side of the connector and it was only reading 2.5 volts at the blue circle in picture.
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I am not sure what is supposed to happen when you do this test as the hot wire is still connected to the coil.
Also, where are the screws that hold the coil... and the coil's ground strap in place?
 

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Discussion Starter #22
Yes the wire was unplugged from cap. I've got the top and screws for ground. I'm saying I jumped a wire from the battery to the spot I have circled and car ran for 10 minutes or so until I unplugged it. The under side is where the original hot wire hooks up.
 

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Yes the wire was unplugged from cap. I've got the top and screws for ground. I'm saying I jumped a wire from the battery to the spot I have circled and car ran for 10 minutes or so until I unplugged it. The under side is where the original hot wire hooks up.
Based on the information that you provided from your tests, the car's hot wire running to the distributor cap's BAT terminal is supplying full battery voltage to the coil... and should be the same as when you ran the temporary "jumper" wire.

The problem with your engine quitting after it gets hot, and then restarting after a cool-down period are normally the ignition module is going bad... or your coil is overheating.... or both.

Before you start to replace parts, you might also want to check the entire length of the coil's hot wire to confirm it is the proper gauge (10-12) and there are no loose connections anywhere that might cause intermittent power loss to the distributor/coil.
 

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didn't read this but....unplug the vacuum advance..sounds wierd but will try to explain. By doing this you are keep the little wires inside were the reluctor is from turning and advancing the timing. The small yellow and green wires are fraigile and many cars we dignosed this way. Intermittant issues..lightly tug on them. If the break right off without much force = rebuild time for the distributor.
 

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Kind of sounds like you're getting it narrowed down but I had a similar issue a while back. During my engine rebuild I had painted both sides of the distributor hold down clamp. That along with the gasket at the bottom of the distributor was preventing the distributor to get a good ground. I think it was just grounding through the drive gear and oil pump. After I wire brushed all of the paint off the bottom of the clamp it ran fine.
 

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So now after getting carb straightened out with a lot of help from sns it's just shutting off. Drove it twice since the sputtering issue. 20 miles first time no problems. Then went to a drive by birthday party then a cruise around my local town was having. Probably 40 miles and some cruising around town for a half hour or longer no problems. Went to get a pizza and it died just as I was pulling away. Fired right up and got 50 feet into the parking lot and died. Wouldn't start. Had it towed home. Got in next morning fired right up and got it back in garage. Started it up and let it idle for maybe 10 minutes shut off. Like someone is turning key off. Wouldn't start up again. Could a module cause this? Havent really started checking things yet. Had fuel in the filter with a brand new pump on it. Will pull I wire off and see if is getting fire when it happens again
So now after getting carb straightened out with a lot of help from sns it's just shutting off. Drove it twice since the sputtering issue. 20 miles first time no problems. Then went to a drive by birthday party then a cruise around my local town was having. Probably 40 miles and some cruising around town for a half hour or longer no problems. Went to get a pizza and it died just as I was pulling away. Fired right up and got 50 feet into the parking lot and died. Wouldn't start. Had it towed home. Got in next morning fired right up and got it back in garage. Started it up and let it idle for maybe 10 minutes shut off. Like someone is turning key off. Wouldn't start up again. Could a module cause this? Havent really started checking things yet. Had fuel in the filter with a brand new pump on it. Will pull I wire off and see if is getting fire when it happens again
I have a 66 Nova that did the same thing. It ended up being a poor connection in the bulkhead connector on the firewall. I separated it and close the wire connector tabs up and placed dielectric grease on the connectors.
 

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Check the connector at the cap it might be frayed or broken explaining the voltage drop under cap & as said before the screws need to be in the coil for proper grounding. Pick up coils do the same thing. You can get a complete drop in GM style distributor brand new for under a $100 complete with coil & cap
 

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After you have checked that the wire that powers the HEI... and all of this wire's connections are up to par, you can google "How to test an HEI coil" and "How to test an HEI pick-up". There are several website articles and youtube videos on these subjects.

From the information I have read (mostly from posts written by Dave Ray/"Ignitionman" on other car forums), the HEI module will normally not fail on its own... unless the thermal paste that coats the underside of the module is missing and the module overheats. More often than not, it's the HEI "coil in cap" that is starting to go bad/overheat that also causes the HEI module to fail. If you just replace the HEI module... and do not replace a bad coil, it is only a matter of time before the existing "bad" coil will cause the new module to fail.
Based on my personal experience dialing-in mine and other HEI's, I have learned a lot of useful information from Dave Ray/ Ignitionman... and he really knows his stuff about HEI's.

If new HEI components are needed, you could replace the existing "coil in cap" and module with with a new "coil in cap" and module and be just fine (as I have used this type of set-up for over 15 years in my HEI without failure).

But something to consider.... (what I would do if I needed to replace a bad coil in my HEI)
If you decide to replace the HEI module and the coil, a recommendation for a more reliable HEI system is to remove and delete the "coil in cap" coil... and install a remote mount oil-filled coil with an MSD HEI Modified Dust Cover (part #8401). By switching to a remote mount coil, you will also be removing some heat within the cap that was generated by the HEI's "coil in cap".

If going this route, the Pertronix Flame-Thrower II is an oil-filled coil with a primary resistance (.600 ohms) and is very close to the primary resistance in the "coil in cap" coil (.500 ohms).
I have also read to stay away from epoxy filled coils... since the oil-filled coils are better at cooling and less prone to internal shorting.

Note: You will also need a coil wire to connect the remote coil to the HEI cap if going to the remote coil set-up.
 

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Replace the distributor with a Davis Unified Ignition HEI unit.
Replace the 12v wire from the bulkhead connector with a thicker gauge wire.
Check and recheck the wiring from your ignition switch to the bulkhead connector on the firewall.
Check and recheck that the distributor body is grounding (clean hold down clamp).
 

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Discussion Starter #33
Checked pick up coil had 878 ohms. Wiggled wires around still 878. So it should be good. New coil and module. Same ****. Gonna test new coil and check clamp on distributor. If all checks out I'm putting back together and if still not right I'll run a hot from battery to coil and see what's how that does.
 

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Checked pick up coil had 878 ohms. Wiggled wires around still 878. So it should be good. New coil and module. Same ****. Gonna test new coil and check clamp on distributor. If all checks out I'm putting back together and if still not right I'll run a hot from battery to coil and see what's how that does.
Did you check the 12 volt lead disconnected & connected for 12 volts? The wire could be loose and not making proper connection
 

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Ok I had 12.43 at the battery and 12.26 at the wire that goes to battery side of the cap. I took the top of the cap to expose the coil. I checked voltage on the coil side of the connector and it was only reading 2.5 volts at the blue circle in picture (see attachment).
Shouldn't it be the same 12.25 I measured at connector that would plug into it?
View attachment 404917
Yes... it should be the same (with the ignition wire connected and key turned to RUN/ON position.

Something didn't seem right with your voltage reading at the cap terminal within the blue circled area (2.5 volts) with the ignition wire plugged in to this terminal (BAT) and key in the RUN/ON position. .... so I removed my dust cover from my HEI to check my voltage at the same terminal (Red arrow in image below).
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Test Results on my HEI:
Engine OFF:
  • Voltage across battery terminals = 12.50 volts
Ignition key turned to RUN/ON position + Engine still OFF
  • Ignition wire disconnect from cap's BAT terminal and voltage measured at the wire = 12.35 volts (positive lead of meter on end of wire and negative lead of meter on engine ground).
  • Ignition wire plugged back into cap's BAT terminal and voltage measured at RED arrow terminal = 12.35 volts (positive lead of meter on cap terminal and negative lead of meter on engine ground).
Check that you have the proper type of connector (female blade) on the end of the ignition wire that attaches to the cap's BAT connector (male blade)... and when attached, the connection should be tight & secure.
Also check the the blade connector from the coil is not broken (but this should have been addressed if you installed a new coil).

Maybe you did not have the voltage meter leads making a good connection when testing this terminal... or the negative lead of the meter may not have been touching a good ground when you observed 2.5 volts.
To confirm a good ground source, check the ground with the positive lead of the meter touching the positive terminal on the battery... you should see full battery voltage if the negative lead of the meter is touching a good ground. Once ground is confirmed, use the same ground location for all voltage tests.

Be sure to also check that the housing for the HEI is acting as a good ground. Connect positive lead of volt meter to positive battery terminal (or any other 12 volt source) and touch the negative lead to the HEI's housing. You should see full battery voltage.
NOTE: You can also check that the HEI housing is grounded with an ohm meter. You should see good continuity between the HEI housing and engine ground.

Can you re-check the voltage as described above and report back.
 

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Checked pick up coil had 878 ohms. Wiggled wires around still 878. So it should be good.
New coil and module. Same ****.
What happened with new module and coil installed?
  • Did the engine run for a few minutes... and then shut off by itself?... or did the engine not start at all?
  • If the engine did run... how long did it run before it shut off?
  • Did you check if the ignition wire was still providing 12+ volts to the coil immediately after the engine shut off... and the ignition key was still in the RUN position?
Once you are able to get the engine running again, can you check the voltage across the Pos and Neg battery terminals with the engine running (should be about 13.5 to 14.5 volts).
 

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Discussion Starter #38
Ok had to run a new wire from the ignition to the hot on the coil. Will stay running now. But its running rough. Take a look at the video of my fuel filter. Not staying full and looks like fuel is spitting up into it.
 

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Glad to hear that you got your HEI's ignition hot wire worked out!
Once this was done, did you check your ignition timing @ idle?

I recall that you had sight windows in your carb's fuel bowls (your carb shown below).
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With you engine running, do you see any gas at the bottom of these windows?
  • If not... with the engine still running, rock the front of your car up-and-down. Do you see any gas at the bottom of the windows now?
  • Try revving your engine. Any changes with the fuel flowing thru the gas filter... and/or fuel level in the carb's fuel bowls?
Also, with your engine running, can you check the voltage across the Pos and Neg battery terminals (should be about 13.5 to 14.5 volts). I just want to confirm that your alternator is not over-charging.
 

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Discussion Starter #40
Yes fuel in the sight glasses have to get a new battery for my meter. I still not sure I'm getting 12v at the connector. When I get a battery for meter I'll post the numbers.
 
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