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Old 10-16-2017, 10:07 PM
Justoldchevys Justoldchevys is offline
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Is your wiring harness all original? If so the wire that supplies power to the coil is probably a resistence wire. Look at it closely you will notice it being different. You will need to remove that wire and replace it with normal wire to provide the correct voltage to the hei coil
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Old 10-16-2017, 10:10 PM
earntaz earntaz is offline
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Originally Posted by Justoldchevys View Post
Is your wiring harness all original? If so the wire that supplies power to the coil is probably a resistence wire. Look at it closely you will notice it being different. You will need to remove that wire and replace it with normal wire to provide the correct voltage to the hei coil
Hopefully however did the conversion would know that -- or maybe not ... a lack of full 12v to an HEI will have issues.
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Old 10-17-2017, 06:46 PM
drdave69 drdave69 is offline
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The engine was running fine when I bought it (April 2016) and did so until this time last year (Oct. 2016). That is when this issue popped up. I have since put in new plugs, wires, ign coil, cap, rotor. Had the timing checked. Had Eric rebuild the Holley and recently had the EFI installed. So far, nothing has solved the issue.
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Old 10-30-2017, 11:45 AM
drdave69 drdave69 is offline
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I finally got around to checking the starting voltage. I pulled off the input voltage wire from the HEI and checked the voltage with key on. It is 11.8 v. In start mode it goes to 9.8 v. It is the same when the engine is up to operating temp. The next thing I am gonna check is the voltage when running but that involves removing the cap from the coil.

I also drove it about 10 miles and it also has a miss. Got to be something wrong with the ignition but I haven't figured it out yet.
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Old 10-30-2017, 05:42 PM
earntaz earntaz is offline
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I finally got around to checking the starting voltage. I pulled off the input voltage wire from the HEI and checked the voltage with key on. It is 11.8 v. In start mode it goes to 9.8 v. It is the same when the engine is up to operating temp. The next thing I am gonna check is the voltage when running but that involves removing the cap from the coil.

I also drove it about 10 miles and it also has a miss. Got to be something wrong with the ignition but I haven't figured it out yet.
I'd still try to "hot wire" it ... 12V lead from + side of battery to the IGN terminal on HEI. That would isolate the ign system from all except the 12V source.

Don't know if this has been mentioned yet. Do you have an electonic tach connected to the HEI? If so, you may want to unplug it also in case the tach is causing an issue ... TAZ
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