HEI wiring?

Hi folks, A friend called today with a no start on an 89 caprice w\TBI. He had injector pulse but no spark (external coil HEI). He had already purchased a module and asked me to install it. I found and replaced a badly burned rotor and cap, original at

140Kmiles. No spark at the coil. I went ahead and replaced the module because it was there. Still no spark. I'm a Ford guy and am very familiar with internal coil HEI but I've never had a chance to get to know this system. Could someone provide me with a wiring diagram or pinouts of the module and coil? I don't want to just throw parts at it. I just don't know where to check for voltage, ground,pickup pulse, etc. The 4 wire coil has me stumped :). Any input is appreciated. Thanks, Tom Adkins