The crank position sensor (CKP) on a 1990 Jeep Wrangler 2.5L four-cylinder is located on the
bell housing, near the
bottom of the engine, close to where the transmission meets the engine. It's usually mounted on the
passenger side (right side as you sit in the driver's seat).
However, you'll need to consult a repair manual specific to your 1990 Jeep Wrangler 2.5L to get the most precise location. A picture in the manual will be invaluable. The sensor itself is usually a fairly small, cylindrical unit.
