Assuming you got the CEL light hooked up to the correct leads, it sounds like a failed ECU. Now that these vans are getting over 30 years old failed ECU's are not uncommon. On 84 - 85 vans there was only one used (Toyota #89561-28010). In the past I've been able to find these fairly cheap on eBay. They have some there now, but the prices they are asking are way bit high ($200+). Perhaps watch craigslist parting out ads, or maybe your local salvage yard? Good luck. Tim