[Gasoline Fumes]

Enough throttle cable slack? Vacuum leak? Plug all open tubes on the intake manifold. Don't play with the throttle stop screw unless you're sure it's been moved. If it looks like the throttle butterfly is closing all the way, leave that screw where it is. There's an idle speed adjusting screw on the throttle body, but it's really for fine adjustments. It normally hidden by a little black rubber plug. It's on the driver's side.

My 1990 Civic Wagon service manual shows a blue wire for the tach. Whether it's green or blue, it should be hooked up to the brown wire coming from the noise suppressor. That should hopefully get the tach working.