For the future, if/when you encounter dead speedometer...

I had a similar experience on my 92 Prelude Si. My speedometer was
working intermittently and stayed at 0 for 99% of the time. I noticed
that when my speedometer is not working, my idle would be very rough.

My guess: Since there is no feedback from VSS (Vehicle Speed Sensor),
the engine fluctuates to compensate for the lack of data.

The fix: Had a mechanic replace the VSS, the symptoms went away.

Cost: You can buy a VSS for less than $200 (www.slhondaparts.com), but
replacing it yourself may not be feasible. The VSS can be located on
top of the transmission, but my VSS was obscured by the engine.

Note: VSS has nothing to do with your car not starting.