System Specifications

1984 Volkswagen Jetta L4-1781cc 1.8L SOHCSECTION System Specifications

Fig. 1 Thermo time switch triggering time:








Control pressure, cold (immediately after starting) ..... see "WARM UP REGULATOR" in DIAGNOSIS AND TESTING.
Control pressure, warm ..... 3.4 - 3.8 bar (49 - 55 psi)
System pressure ..... 4.7 - 5.4 bar (68 - 78 psi)
Leak test (min. residual pressure) 3.0 bar accumulator:
after 10 min ..... 2.6 bar (38 psi)
after 20 min ..... 2.4 bar (35 psi)
Thermo-time switch activation period ..... See Chart, Fig. 1.
Cold start valve:
min voltage ..... 11.5vdc
injection time ..... see thermo-time switch chart
Auxiliary air reg min voltage ..... 11.5vdc
Control pressure regulator:
min voltage ..... 11.5vdc
heater resistance ..... 16 - 22 ohms
Fuel injectors:
opening pressure ..... 3.5 - 4.1 bar (51 - 59 psi)
difference between injectors ..... 0.6 bar (8.5 psi)
Air preheat thermostat
open below ..... 20°C (68°F)
closed below ..... 34°C (93°F)

Ignition timing/CO adjust
All cars: engine at full operating temp. (Oil at 80°C (176°F), all electrical equipment off, and idle stabilizer bypassed (by plugging the connectors together).

Ign. timing (vacuum hoses connected):
Automatic Trans. ..... 3° +/- 1° ATDC
Manual Trans. ..... 6° +/- 1° BTDC
Idle speed:
Calif. ..... 940 +/- 60 rpm
Non-Calif ...... 925 +/- 75 rpm
Idle mixture (Oxygen sensor connected, PCV hoses at valve cover disconnected and open):
Duty cycle method:
Calif. ..... 45° +/- 6° (50% +/- 6%)
Non Calif. ..... 45° +/- 6° (50% +/- 6%)
Exhaust analyzer method:
Calif. ..... 0.3 - 1.2%
Non-Calif. ..... 0.3 - 1.2%

RENDER: 1.0x

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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.