Chrysler Concorde 2004 Service Manual page 787

P0300-MULTIPLE CYLINDER MISFIRE —
TEST
7 Warning: The fuel system is under a constant pressure (even with the engine
off). Before testing or servicing any fuel system hose, fitting or line, the fuel
system pressure must be released.
CAUTION: After each actuation of the Fuel Injector, start the engine to clear
the cylinder of fuel. Failure to do so could cause engine damage.
Install a Fuel Pressure Gauge to the fuel rail.
Start the engine and allow the fuel pressure to reach maximum pressure.
Turn the engine off, leaving the ignition on.
Using the DRBIII , actuate the Fuel Injector for the cylinder that indicated the
misfire.
Monitor the fuel pressure gauge.
Does the fuel pressure gauge indicate a drop in fuel pressure?
Yes → Go To 8
→ Go To 9
No
8 Check for any of the following conditions/mechanical problems.
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
Are there any engine mechanical problems?
Yes → Repair as necessary.
→ Go To 17
No
9 Turn the ignition off.
Disconnect the Fuel Injector harness connector.
Ignition on, engine not running.
With the DRBIII , actuate the ASD Relay.
Using a 12-volt test light connected to ground, probe the ASD Relay Output circuit at
the Fuel Injector harness connector.
Does the test light illuminate brightly?
Yes → Go To 10
→ Repair the ASD Relay Output circuit.
No
10 Turn the ignition off.
Disconnect the Fuel Injector harness connector.
Ignition on, engine not running.
Using a 12-volt test light connected to 12-volts, probe the Injector Control circuit.
With the DRBIII , actuate the Fuel Injector.
Does the test light blink/flicker?
Yes → Replace the Fuel Injector.
→ Go To 11
No
ACTION
Perform POWERTRAIN VERIFICATION TEST VER - 5 - NGC.
Perform POWERTRAIN VERIFICATION TEST VER - 5 - NGC.
Perform POWERTRAIN VERIFICATION TEST VER - 5 - NGC.
DRIVEABILITY - NGC
Continued
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APPLICABILITY
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All
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