200 Quattro Wagon L5-2226cc 2.22L SOHC Turbo (MC) (1989)
Integral Fuel Pressure Regulator W/Push-Up Valve
NOTE: This type pressure regulator is a serviceable part. The pressure can be adjusted by adding or removing shims. Adding shims increases
regulated pressure and removing shims reduces pressure. Also, damaged O-rings can cause a system pressure loss.
If system pressure is too high, check for pinched or kinked fuel return line. If fuel line is not restricted, service or replace pressure regulator as
necessary.
RESIDUAL PRESSURE CHECKING
If system pressure is OK, open valve on fuel gauge block and let engine idle for a few moments, then shut engine "off".
1.
Check residual pressure on gauge after 10 minutes and again after 20 minutes.
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After 10 minutes - 43 psi (3 bar) minimum.
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After 20 minutes - 40 psi (2.8 bar) minimum.
If residual pressure is less than specified, check for:
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Leaking fuel pump check valve.
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Insufficient air flow sensor plate free play.
^
Leaking fuel system connections or leaking injectors.
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Leaking cold start valve.
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Leaking control plunger seal (fuel leaking into air filter box from fuel distributor).
If these check out OK, service or replace fuel pressure regulator as necessary.