1987 Volkswagen Quantum Base, AutomaticFACTORY OEM SERVICE PROCEDURE

After Start Enrichment

  1. Connect test harness between differential pressure regulator and vehicle harness. Connect multimeter to test harness. Disconnect wiring from coolant temperature sensor. Ground high tension lead (terminal No. 4) from ignition distributor.
  2. Crank starter for 3 seconds. Return key to "ON" position. Differential pressure regulator current reading should increase to more than 120 mA for 20-50 seconds, and return to 80-110 mA range.
  3. If not, check starter signal to terminal No. 24 of ECU connector. Check signal from relay board to starter motor (terminal No. 15a on starter). On 5-cylinder models, check voltage between ECU terminals No. 2 and 21. See VOLTAGE CHECKS and RESISTANCE CHECKS CHARTS in this article for appropriate testing procedure. If all wiring is okay, 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:

  • • 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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