LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Audi >> 1989 >> 90 Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Basic Testing >> Fuel System >> Fuel Pressure (Cis Digital Control) >> System Pressure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

System Pressure

  1. Connect Pressure Gauge (VW 1318) between line from fuel distributor to cold start valve and test port connection on lower chamber of fuel distributor, using Adapter Fittings (VW 1318/5). Test port is sealed by a threaded plug. Bridge fuel pump relay (located on fuse/relay panel) with Jumper Switch (US 4480/3).
    NOTE: Fuel pump may also be activated by jumpering 12 volts to by-pass terminal on fuse/relay panel. See WIRING DIAGRAMS - CEC article in this section.
  2. Open valve on pressure gauge (points at cold start valve line when open) and activate fuel pump. System pressure must be 68-78 psi (4.7-5.4 kg/cm2 ). If pressure reading is low and fuel pump delivery quantity is good, adjust or replace regulator assembly.
  3. If pressure reading is high, disconnect fuel tank return line from fuel distributor. Repeat test. If reading is correct, check for plugged return line. If reading is incorrect with line open, replace regulator assembly.
  4. If pressure is not within specification and regulator valve has been replaced, adjust system pressure at fuel distributor. See ADJUSTMENTS article in this section.
scientia non olet · About LEMON Manuals