Rep Power: 0

So... I have a 2000 Civic Ex coupe that has an issue with the speedometer, I just bought the car, and the girl I bought it from said it was working a month ago (no proof it was). The car was originally an automatic transmission car (I believe, at least all interior components except the shifter and clutch suggest it was an automatic, including the dash) and is now a 5 speed. I also believe the engine is aftermarket, it is the D16Y8 (love the engine, its in my other civic too) and the oxygen sensor is missing, but there is no check engine light on. I have never worked on imports, but could fix anything on an old ford, so for you mechanics out there you know I'm in a whole different world. I don't know why, but the speedometer is not working at all no matter how fast or slow I'm driving. I don't know what to look for, but if someone can tell me I'm sure I can figure it out.

 
Rep Power: 518

Does it have a check engine light that actually works?

Is the light actually connected to the computer at all, or is it jumpered to the oil pressure/alternator light?

Plug in a real scanner (or Scangauge, etc.) that can give live operating data on the fly.
First check for any fault codes and proceed with troubleshooting accordingly.
(You'll need to know if it was converted to OBD1 also, a typical code reader won't talk to OBD1 system.)

Does scanner display accurate VSS data while driving?
Does scanner display any O2 sensor data?

 
Rep Power: 0

I'll have the computer checked, but I know the check engine light works because it came on when I stalled the car the first time I drove it (very low idle, didn't give it enough gas)

 
Rep Power: 518

It's easy for someone to rewire it to make the light come on at about the right time.....

Now figure out if it's really connected to the computer. I have a strong suspicion it is not.

 
Rep Power: 0

so, I texted the previous owner, and the transmission was originally automatic (now 5 speed), and when she did the transmission conversion, she swapped the computer, but she doesn't know what type of computer she put in.