200 Quattro Wagon L5-2226cc 2.22L SOHC Turbo (MC) (1989)
Warm Up Regulator: Testing and Inspection
To accurately test the warm-up regulator, system pressure must be correct.
SYSTEM PRESSURE CHECKING
NOTE: Before performing service on the fuel system, relieve system pressure by covering the hose connection at the cold start valve with a clean rag
and loosening slowly.
Checking System Pressure
1.
Install fuel pressure gauge (with shut-off valve on one side of "tee") between fuel distributor and warm-up regulator, as shown in illustration.
Gauge must be installed with shut-off valve facing regulator.
2.
Close shut-off valve.
3.
Start engine and let idle, while observing pressure on gauge (this is the system operating pressure).
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Pressure should be 84 - 96 psi.
If pressure is too low, possible causes are:
Fuel lines and connections leaking, kinked or pinched.
Fuel pump pressure relief valve defective.
Fuel filter and/or mini filter (in fuel distributor inlet banjo bolt) plugged.
Fuel pressure regulator in fuel distributor dirty or defective.
Fuel pump defective.
If pressure is too high, possible causes are:
Pinched, kinked or otherwise restricted fuel return line.
Defective pressure regulator in fuel distributor.
CONTROL PRESSURE CHECKING (COLD)
NOTE: Engine coolant temperature must be 68° - 86°F (20° - 30°C)
1.
Install fuel pressure gauge as in system pressure check.
2.
Open shut-off valve.
3.
Start engine and observe pressure on gauge after 30 seconds (but not longer than 1 minute).