This is only true if this Chevy Asto van originally was equipped with an AIR injection system which was at some point in the vehicle's life removed. If the Astro van's original air injection system was removed, then yes, you will need to find an AIR injection system (either new, rebuilt, from a wrecking yard, or parts store) and have it re-installed.
If this Chevy Astro van was never equipped with an AIR injection system you do not need to install one in order to pass the California smog check. Out-of-State vehicles, so long as they have not had their emission systems tampered with (and exhaust emissions fall below California emission cut scores) can pass the smog check and legal register in California without the addition of any non-factory equipped smog parts.
Depending on your Chevy Astor van's engine size it may or may have not been equipped with an Air Injection system. The Motor Emissions Application Guide indicated that the 4.3 liter engine, both 49-state emissions equipped (federal) and California emission equipped did have a Pump Style are injection system. We are unable to find any other engine size for the 1989 Chevy Astro van. Based on our findings it appears you will need to install an AIR injection system on this Chevy Astro van before it will pass the smog check. Verify this with a hands on diagnosis at a smog check repair center.
