Old school GM Hei help...

Old 07-23-2014, 09:38 AM
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Join Date: May 2006
Location: Pelahatchie, MS
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Default Old school GM Hei help...

Working on a 66 GTO for a friend. Body work mostly. But the engine was just installed prior to bringing it to me. (Owner drove it over, first time it had moved in almost 30 years). wiring was hacked, and I straightened it out. Engine is mostly stock 400 with 6x heads and a mild cam, backed by a Muncie 4 speed. I pulled the trans because the installer did not tighten the flywheel bolts properly, and it had a slight knock. ( I did this between Thanksgiving and Christmas). Couldn't get the trans in by myself, as it seems I am getting old... Last week i finally got some help and put the trans in, and finished buttoning everything up as I had time.

Owner came by a few days ago, and we tried to get it running. Put fuel in the new tank I had installed, and I put some on the float bowls of the new Holley via the overflow tubes. Connected the battery and spun it over.

Fired right up and ran. I would say about 45 seconds or so and died. Got my trusty spark tester out, and no fire to number one. Put my multimeter on the power wire for the HEI, and battery voltage was present. The distributor in the car is an aftermarket GM HEI copy,. Owner said he thought it was an Accel, but I am not so sure. It has a red cap, and did not come with a coil, so they had installed an old coil. I have a new Accel for a SBC in the parts stash so I swapped the cap/coil over, no fire.

Owner came by today and we tried a new module with the same result. Verified dizzy would spin by motor, dizzy is not loose, time is where it was when it was running. Pulled a valve cover and verified cam was turning (Doubtful a new chain broke, but you never know). Ran a hot wire from the battery straight to the dizzy, same result...

SOOO... power into dizzy, no voltage out, new dizzy, new coil, new module...

Any ideas?
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Old 07-23-2014, 11:51 AM
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Join Date: May 2014
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I have seen this problem before, it turned out that the guy that installed the engine in this particular car actually pinched the tachometer wire, grounding it and killing the module pulses. I have also seen where the ground "tang" was left out when coil was changed.
Here is a good thread for troubleshooting the HEI http://chevythunder.com/hei_troubles...ge_2_coil_.htm
Hope this helps!
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