200 Quattro Wagon L5-2226cc 2.22L SOHC Turbo (MC) (1989)
Fuel Pressure Regulator: Testing and Inspection
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.
NOTE: Gauge must be able to measure up to 103 psi (7 bar).
3.
Start engine and let idle, while observing pressure on gauge (this is the system operating pressure).
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Should be 84 - 96 psi (5.8 - 6.6 bar).
If pressure is too low, check for:
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Plugged or restricted fuel filter.
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Faulty fuel pressure relief valve in fuel pump, or defective pump.
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Pinched, or kinked fuel line from pump to fuel distributor.
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Fuel hoses or connections leaking.
If these check out OK, service or replace the pressure regulator as necessary.