1987 Volkswagen Quantum Base, StandardFACTORY OEM SERVICE PROCEDURE

Cold Acceleration Enrichment

  1. Connect test harness between differential pressure regulator and vehicle harness. Connect multimeter to test harness. Disconnect wiring from coolant temperature sensor. Remove intake air boot.
  2. Turn ignition on and lift sensor plate quickly to full open position. Differential pressure regulator current should increase to more than 110 mA, and drop back to 80-110 mA range. If not, check potentiometer and wiring to ECU. If potentiometer and wiring are good, replace ECU.
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:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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