Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1991 Mercury Capri Base, AutomaticFACTORY OEM SERVICE PROCEDURE
Pinpoint Test STI - Self-Test Input
NOTE:
Enter this test only when sent here from QUICK TESTS.
STI CIRCUIT PIN IDENTIFICATION
| Circuit | ECA Pin | BOB Pin | Wire Color | |
|---|---|---|---|---|
| STI | ||||
| 1.3L | 1K | 48 | YEL/GRN | |
| 1.6L | 1W | 48 | YEL | |
- Turn ignition off. Install BOB. Leave ECA disconnected. Connect test light between STI test pin on BOB and 12-volt source. If test light comes on, go to PINPOINT TEST STO . If light does not come on, go to next step.
- Leave test light connected. Ground STI connector. If test light does not come on, repair open circuit between STI connector and ECA.
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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