PDA

View Full Version : HEI trouble - no spark



qwik1320
04-22-2007, 10:25 AM
Long story bear with me please...

Last fall my 73 had trouble starting, it would actually start after you let go of the key. Figured it was the ignition switch so I replaced it and got it started in the garage and then would not start at all. Thought the 20 year old HEI finally had enough, tested OK but readings were at the low end of the acceptable range so I swapped it out for a new GM Perf Parts. Now I still get no spark. Have 12+V when the key is "ON" but only about 9V when you turn the key to "START". The wire is good (get the same reading right at the fuse block).

Per the advice of someone at NastyZ I swapped the hot wire to the HEI over to the BATT terminal on the fuse block to see if I could start it...since that was showing 12+V...still no luck.

I hate electrical gremlins....any ideas??

HILROD
04-22-2007, 06:38 PM
The stock ignition wire is a resistor for point type ign. Put the hot wire to the IGN. side of the fuse box. Check at the plug wires for spark. If it has spark it's another problem. For what it's worth I worked on a similar problem on a 73 Charger. Per the owners request I replaced the distributor to the newer solid state type. The car had a history of hard starting, and ran so so once running. While it was being worked on, I took some of the gas out for my lawn mower to finish my lawn. The gas was maybe 4-5 months old. The mower wouldn't run. The gas wouldn't light with a lighter. The fuel sytem then got flushed.

qwik1320
04-22-2007, 07:18 PM
I have a 10 gauge wire hooked directly from the IGN terminal on the fuse block to the BATT terminal on the HEI. No spark, not even a weak one in a pitch black garage. The car has been wired this way for about 20 years, never had a problem...until now.

The thing I'm confused about is the 3-4V drop when you turn the key from "ON" to "START" - is this normal? Do you need 12V (or very close to it) for the HEI to fire? As it stands now I'm only getting 8-9V to the HEI when cranking.

Railing68
04-22-2007, 07:54 PM
Replace the module, should cost 15-$35. My truck did this and had a newer HEI and new cap etc just stopped firing one day recently. $17 module and fired on the first crank! HEI does like 12V but a little below shouldn't be a problem. SS

qwik1320
04-23-2007, 04:01 PM
:seizure: Woohoo! Problem solved. I disconnected the tach and she fired right up...go figure. Now time to set the timing and :drive: