C3Turbo

It was suggested that I post this here instead of the C3 forum. I've taken on my father's project 76 stingray. The car is equipped with an 87 iroc-z tuned port fuel injection system and an Accel DFI standalone PCM. He's running a remote-mounted turbo (which is incidentally way too small for the application) and an iroc-z 5-speed transmission.

I continually get error code 72 (cam/crank signal error) about 5 minutes after startup. The system is using a stock-style GM HEI distributor for a cam signal. There is no crank signal/trigger wheel in use. The car will start up and run fine, but after 3-5 minutes this error code will present itself. Rather than just shutting off immediately upon loss of signal, the PCM will continue to run by forcing it's own cam/crank position value. That's nice, except it's probably about 15-20* advanced from the actual/original position. As a result, timing is way off and the car isn't even able to idle properly because it can't pull enough timing to slow it down.

As a band-aid I've adjusted timing tables to be correct after this value is forced as it accounts for 95% of the drive cycle. But, it would be nice to actually fix the issue and not idle at 400rpm until the error code presents itself. I've already tried replacing the module and then the entire distributor. I've also confirmed the wiring in correct (it won't start at all without that signal). Do I just need to upgrade to a dual-sync distributor and get it over with? Or, is there something else I don't know that I could check? Thanks in advance for any and all responses!