Did you remove the codes after the repairs? if so fit a pressure gauge to the fuel line , start the engine and note pressure should be around 50 psi , switch engine off pressure must hold, if it leaks back check the fuel pump return valve, fuel rail pressure regulator, and injectors , if the pressure is low and no leaks replace the fuel pump, if the fuel flow through the return hose is low replace the fuel filter.
The computer might have to be reset.Check you manual to see if you can reset it or try disconnecting the battery.
SOURCE: My 200 jeep grand cherokee
Before all this work was performed and money spent on parts, was the PCM checked for any DTC's?? If so, what was the read out?
SOURCE: how any oxygen sensors are on a 1999 grand cherokee laredo 4.0 & were is it/they located?
On Grand Cherokee oxygen sensor locations for 4.0 and 4.7 engines, check this diagrams...
The Oxygen Sensors (O2S) are attached to, and protrude into the vehicle exhaust system. Depending on the emission package, the vehicle may use a total of either 2 or 4 sensors.
Federal Emissions Package (4.0L and 4.7L engines):
Two sensors are used: upstream (referred to as 1/1) and downstream (referred to as 1/2). With this emission package, the upstream sensor (1/1) is located just before the main catalytic convertor. The downstream sensor (1/2) is located just after the main catalytic convertor.
California Emissions Package (4.0L engine):
On this emissions package, 4 sensors are used: 2 upstream (referred to as 1/1 and 2/1) and 2 downstream (referred to as 1/2 and 2/2). With this emission package, the rear/upper upstream sensor (2/1) is located in the exhaust downpipe just before the rear mini-catalytic convertor. The front/upper upstream sensor (1/1) is located in the exhaust downpipe just before the front mini-catalytic convertor. The rear/lower downstream sensor (2/2) is located in the exhaust downpipe just after the rear mini-catalytic convertor, and before the main catalytic convertor. The front/lower downstream sensor (1/2) is located in the exhaust downpipe just after the front mini-catalytic convertor, and before the main catalytic convertor.
California Emissions Package (4.7L engine):
On this emissions package, 4 sensors are used: 2 upstream (referred to as 1/1 and 2/1) and 2 downstream (referred to as 1/2 and 2/2). With this emission package, the right upstream sensor (2/1) is located in the right exhaust downpipe just before the mini-catalytic convertor. The left upstream sensor (1/1) is located in the left exhaust downpipe just before the mini-catalytic convertor. The right downstream sensor (2/2) is located in the right exhaust downpipe just after the mini-catalytic convertor, and before the main catalytic convertor. The left downstream sensor (1/2) is located in the left exhaust downpipe just after the mini-catalytic convertor, and before the main catalytic convertor.
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SOURCE: 1999 jeep grand cherokee laredo v6 4x4 won't fire on all 6 cylinders just 4 why?
Plenty of causes. Plugs, valves. rings, numerous electronic/electrical faults. Diagnose vehicle and eliminate problems one by one.
is different color. i need help knowing which wires get connected to which.
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