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.
1985 Ford EXP 1.6 4, Standard, MTXIIIFACTORY OEM SERVICE PROCEDURE
Extended Idle Air By-Pass System
- With engine at normal operating temperature and transmission in "N", begin timing. If after 2 1/2 minutes thermactor by-pass valve dumps secondary air through vents, system is okay. If not, check routing and condition of hoses. If hoses are okay, check by-pass valve function.
- If valve is okay, check battery voltage to ITS and continuity through normally closed ITS while manually cycling switch. If okay, check that solenoid is functional and actually opens to close off vacuum. If solenoid is okay, turn engine "OFF" and ignition "ON". After 2 1/2 minutes, check vacuum signal to solenoid.
Factory Service Tools
Use the Manual With the Right Hardware
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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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