1983 Plymouth Horizon 2.2 C, StandardFACTORY OEM SERVICE PROCEDURE

2.6L Engine

  1. Check vacuum hose condition, routing and installation. Start cold engine and run at idle. Increase engine speed to 2500 RPM. Secondary EGR valve should not operate. If secondary EGR valve operates, replace thermo valve.
  2. Warm engine to at least 150°F (66°C). Accelerate engine to 2500 RPM. Secondary EGR valve should operate. If it does not, inspect EGR valve or thermo valve and replace as necessary.
  3. Disconnect Green striped hose from nipple on carburetor. Connect vacuum pump to hose. Pull sub-EGR valve by hand and apply 6 in. Hg vacuum.
  4. If engine idling speed becomes unstable, the secondary valve is operating properly. If no change, the EGR valve or thermo valve is not operating properly.
  5. Disconnect vacuum pump. Reconnect Green striped hose to carburetor. Disconnect Yellow striped hose. Connect vacuum pump to Yellow striped hose. Apply 6 in. Hg vacuum with hand pump.
  6. If engine idling speed becomes unstable, primary valve is operating properly. If no change, the EGR valve or thermo valve is not operating properly.
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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