hello ,

i recently bought a lude 1992 H22 i believe.its not ina brilliant condition but im workin on it.yesterday the speedometer stopped workin and its showing the check engine light.its milage meter alread dont work.
now this mechanic i know has code machine buit cant find the connector or what ever its called where he could connect the computer.
i have no idea what wrong but hes saying it must be the sensor.
could any one tell me where actually i can hook up the computer and what can i do about the milage meter.Cant figure aout the fuel mialge and oilchange time beacuse of that .help needed and some good advise.