Diagnosis:

Using the DRB II and the 1990 Powertrain Diagnostic Manual for 2.2/2.5L Turbo Engines (Publication # 81-699-0024), check the system for fault messages. If a "Boost Limit Exceeded" fault message is displayed, perform diagnostic test DR-31 in the diagnostic manual. If the diagnostic procedure does not resolve the problem, perform the following test.

1. Following the procedures outlined on page 8D-13 of the 1990 Front Wheel Drive Car Service Manual (Publication # 81-270-0102), set basic ignition timing to 12~ BTDC.

2. Connect the coolant temperature sensor connector.

3. With the engine shut off, clear all fault messages from memory using the DRB II tester.

4. Disconnect both vacuum/pressure lines to the turbocharger actuator. Plug both lines.

5. Disconnect the vacuum line going to the dashboard boost gauge at the nylon vacuum line elbow located on the right side of the engine. Connect a two foot length of 5/16" vacuum line at this elbow. Connect the other side of the vacuum line to the "A" (top) port of the turbo actuator.

6. On a highway with clear driving conditions, road test the vehicle. Accelerate at wide open throttle in each of the first four gears while an assistant observes the boost level on the DRB II. If the boost is more than 11 psi at any time and/or if fault message "Boost Limit Exceeded" is again stored in memory, the turbocharger minimum boost level is out of specification. WARNING: OBSERVE ALL LOCAL SPEED LIMITS AND LAWS WHEN PERFORMING THIS TEST!

7. If the boost level found in step # 6 is over 11 psi, perform the following repair.