LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Jeep >> 1987 >> Comanche Base, 2.1 B >> Repair and Diagnosis >> Engine Performance >> System >> Spark Control System >> Testing >> Spark Coolant Temperature Override Switch >> Single-Function For Standard Cooling (4-Cylinder)
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Single-Function For Standard Cooling (4-Cylinder)

Disconnect vacuum hose from distributor vacuum advance mechanism and connect vacuum gauge to hose. Start engine. With coolant temperature below 120°F (49°C), manifold vacuum should register. Disconnect vacuum hose from port "4" of delay valve and cap. Manifold vacuum should not register until coolant temperature reaches about 120°F (49°C). If valve fails these tests it must be replaced. See Figure .

NOTE: Ported vacuum is not available with throttle closed. Ported vacuum is available at part throttle (equivalent of 1000 RPM).
scientia non olet · About LEMON Manuals