Where is the computer on a 1988 ford econoline van e-150 located?

A 1988 Ford Econoline E-150 van did not come with an onboard computer in the sense of a modern vehicle's central computer system. There wasn't a single, centralized computer controlling various functions. Instead, any electronic control units (ECUs) would have been relatively simple and dedicated to specific systems (like the fuel injection). These would be located somewhere under the hood or near the dashboard, depending on the specific system. There's no single "computer" location to point to.