Colt L4-1597cc 1.6L SOHC Turbo VIN F FI (1988)
stops and NO fuel pressure is observed, refer to COMPUTERIZED ENGINE CONTROLS to diagnose the fuel pump power supply problem.
7. If the results of the measurements made in step 6 are not within the standard values, refer to the symptoms listed below to determine the probable
cause and make the necessary repairs before re-testing.
a.
Fuel pressure too low:
1.
Clogged fuel filter---Replace
2.
Fuel bleeds down to return hose---Replace the fuel pressure regulator
3.
Low pump output pressure---Check for leak in-line or replace fuel pump
b.
Fuel pressure too high:
1.
Regulator stuck closed---Replace the fuel pressure regulator
2.
Clogged or bent fuel return hose---repair hose
c.
No difference with or without vacuum connected:
1.
Non-responsive regulator---Replace the fuel pressure regulator
2.
Plugged vacuum line or no source vacuum---replace line or repair vacuum source
8. Stop the engine and check for a change in fuel pressure readings. Pressure should hold for 5 minutes. If the gauge reading drops, observe the rate
of drop. Determine the cause according to the following symptoms.
a.
Fuel pressure drops slowly:
1.
Injector leakage---Identify leaking injector and replace.
2.
Regulator is leaking to return line---Confirm and replace regulator.
3.
Check valve in the fuel pump is leaking---Replace the pump.
b.
Fuel pressure drops immediately:
1.
Regulator is leaking to return line---Confirm and replace regulator.
2.
Check valve in the fuel pump is open---Replace the pump.
