Please Help
08-06-2014, 03:24 PM
#1
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Model: Cherokee
Please Help
i have a 2000 Jeep Grand Cherokee and am having fuel problems i need to get the pressure tested i have someone willing to do it but they need to know what the pressure is supposed to be when car is on and when car is off does anyone have these specs please help me.
08-06-2014, 04:38 PM
#2
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Year: 1999
Model: Cherokee
Engine: 4.0
Found this for a 1996 grand cherokee. It's also the same for a 2000 cherokee. So I'd imagine it's the same for all straight six 4.0 engines ( assuming that's what you have).
49 psi running, plus or minus 5 psi. Should hold 24 psi for 5 minutes after shut down.
DIAGNOSIS:
Basic fuel system diagnostics should be used as outlined in the appropriate service manual. A brief recap of the basic diagnostics follows:
Fuel pressure specification - 49 psi - plus or minus 5 psi.
High fuel pressure indicates problems with the fuel pressure regulator. Refer to the service manual for regulator diagnosis. Do not replace the fuel pump for high pressure.
Low fuel pressure - Low pressure could indicate a pump problem or it could indicate a plugged fuel filter or restricted fuel line or no fuel in the tank. Be sure to check these items before replacing the fuel pump.
Fuel System Leak down - When checking fuel pressure be sure to check the integrity of the system after shut down. With the fuel pressure gauge connected, shut the engine off and observe the pressure gauge. The system should maintain at least 24 psi for five minutes after shut down. If the pressure bleeds off quicker, it could indicate that an injector is leaking down or that the pressure regulator is leaking. This can lead to driveablity problems and require further diagnosis.
49 psi running, plus or minus 5 psi. Should hold 24 psi for 5 minutes after shut down.
DIAGNOSIS:
Basic fuel system diagnostics should be used as outlined in the appropriate service manual. A brief recap of the basic diagnostics follows:
Fuel pressure specification - 49 psi - plus or minus 5 psi.
High fuel pressure indicates problems with the fuel pressure regulator. Refer to the service manual for regulator diagnosis. Do not replace the fuel pump for high pressure.
Low fuel pressure - Low pressure could indicate a pump problem or it could indicate a plugged fuel filter or restricted fuel line or no fuel in the tank. Be sure to check these items before replacing the fuel pump.
Fuel System Leak down - When checking fuel pressure be sure to check the integrity of the system after shut down. With the fuel pressure gauge connected, shut the engine off and observe the pressure gauge. The system should maintain at least 24 psi for five minutes after shut down. If the pressure bleeds off quicker, it could indicate that an injector is leaking down or that the pressure regulator is leaking. This can lead to driveablity problems and require further diagnosis.
09-24-2014, 08:05 PM
#3
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Year: 1997
Model: Grand Cherokee
Engine: 4.0 I-6
I check my fuel pressure today on my '97 GC,4.0, using O'Reilly's gauge. The needle vibrated (not oscillated, it was a blur) from 42 to 49 or 50. I don't know if their gauge is bad or if my fuel pump is screwed up. The last few days it has been dying. Just shuts off and then you can restart it, sometimes not right away, you have to wait a minute or so. Sometimes it will run fine for 20 or 30 minutes, other times it shuts off every few minutes.
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