FixVault
Home › Ford › 1993 › Escort Base, Standard › Repair and Diagnosis › Accessories & Equipment › Cruise Control Systems › Testing › Pinpoint Test D - Speed Fluctuates

Pinpoint Test D - Speed Fluctuates

  1. Verify condition. Check throttle linkage for proper operation and adjustment. Service and adjust as necessary. If throttle linkage is okay, check continuity of wiring between servo and amplifier. If continuity exists, go to next step.
  2. Check vacuum hoses. Repair and replace as necessary. If vacuum hoses are okay, test check valve. Also check aspirator check valve (Cougar 3.8L SC and Thunderbird 3.8L SC). Apply 18 in. Hg vacuum to check valve(s). If vacuum does not hold, replace check valve. See PINPOINT TEST A for procedure. If check valves are okay, on all models except Cougar and Thunderbird, perform appropriate SERVO test under DIAGNOSIS & TESTING.
  3. Replace servo if necessary. On Continental, if servo is okay, go to step 4). On all models except Continental, if servo is okay, check speedometer cables for improper routing, crimping and binding. Service as required. If speedometer cables are okay, go to next step.
  4. Check VSS for free operation. If VSS is not operating properly, replace it. If VSS operates freely, perform VEHICLE SPEED SENSOR (VSS) test under DIAGNOSIS & TESTING. Replace VSS as necessary. If VSS is okay, test vacuum dump valve. Replace or adjust as necessary. If dump valve is okay, go to next step.
  5. Perform AMPLIFIER test under DIAGNOSIS & TESTING. If cruise control problem is corrected after test, replace amplifier. If problem is not corrected, check circuit connectors for security.
About FixVault