HEI Problem

[pdxhall]

If the truck was running fine and now it's not why would the wiring hook up be wrong. It has to be something that has failed or come loose. Pull a plug wire and check for spark first.

[Rich 5150 69]

Originally Posted by pdxhall

If the truck was running fine and now it's not why would the wiring hook up be wrong. It has to be something that has failed or come loose. Pull a plug wire and check for spark first.

GRS original post said it was coming from the firewall plug, ( resistor wire....?, only getting 7 volts ) he needs direct from the ignition pink wire. Plus those plugs have always been a source of failure with resistance and corrosion.

[grs]

Originally Posted by Rich 5150 69

GRS original post said it was coming from the firewall plug, ( resistor wire....?, only getting 7 volts ) he needs direct from the ignition pink wire. Plus those plugs have always been a source of failure with resistance and corrosion.

When I crank the truck to start it. I get 7 t0 8 volts to the hei. When it is in run position with the key on it is 12 volts. I have replaced the module, cap, and rotor. I may just go ahead and replace the coil too before trying to start it. And I am going to run a 12 gauge wire from ing. switch , or fuse to the hei.

[Gobuffalo]

The rotor my have a hole burned thru the middle of it. It will ground the coil to the top of the distributor shaft. It's a common problem when the plugs get warn.
In 1975, when the HEI became standard in everything (74 for Corvettes), the spark plug gap was .065. A GM service bulletin came out to change the gap to .045 because of holes burned thru rotors.