Low cylinder compression on your Ford Explorer will absolutely cause it to
fail the smog test. There is not much you can do at this point except to
repair the cylinder heads if that's where the compression leak is coming
from. Remember low compression can also be due burned valve/s. In this case
it doesn't matter much though because either way your Ford's engine will
need top-end work; the heads will have to be removed, possibly resurfaced,
and the head gaskets replaced.
You can try applying to California's CAP (Consumer Assistance Program) to
pay for getting your Ford Explorer fixed, but more then likely they will
reject to pay for repairs (mechanical part) once they find out it failed the
smog check because of engine compression; which is technically not an engine
emissions fault, but rather an engine mechanical fault. CAP only pays (up to
$500) for emissions related repairs specifically. Once you repair the
compression problem and your Ford still fails the smog check, CAP will pay
for the emissions repairs and get your Ford to pass the smog inspection.
