You can get a fuse box diagram for a 1990 Geo Prizm at your local auto parts store or at the library. Another way to get one, is to contact a local Geo dealer.
One of the best help you can find on the subject is located on:http://home.sprynet.com/~dale02/
At the Nico website
I own a 1989 Sunbird GT turbo and the vacuume line diagram is located under the hood on the top left corner.
you can find it in a workshop manual
Look on the underhood sticker.
what do u want a diagram for I agree with the previous answer, you did not specify what kind of diagram you want. Vacuum, Electrical, firing Order etc. etc.
Autozone dot com.
.41 is the gap specified by the Haynes manual for the 1990 Geo Prizm.
Where is the ecm located on a 1990 cadilliac brougam
1990 GEO PRIZM code 12 = RPM Signal Distributor, distributor circuit,starter signal circuit, igniter circuit igniter, ECM 1990 GEO PRIZM code 71 = EGR EGR system including hoses,gas temperature sensor circuit, gas temperature sensor, vacuum switching valve for the EGR circuit, ECM