Cold Start

[97JGC05]

97 JGC 6cyl 133M. Cranks 3-5 x before starting in morning and after setting 90 mins or more. New plugs and scoped everything came out fine. Any ideas???
Don

[JeepForever]

Please clarify "Cranks 3-5x". Do you mean "3-5 seconds"?. I take it it's starting - just with some effort? Let us know how it drives once it starts, and we can help trace the problem.

[Bob D.]

Originally Posted by 97JGC05

97 JGC 6cyl 133M. Cranks 3-5 x before starting in morning and after setting 90 mins or more. New plugs and scoped everything came out fine. Any ideas???
Don

Fuel system- falling fuel pressure after the engine is off. Can be checked with a fuel gage at the rail.

[97JGC05]

Originally Posted by 97JGC05

97 JGC 6cyl 133M. Cranks 3-5 x before starting in morning and after setting 90 mins or more. New plugs and scoped everything came out fine. Any ideas???
Don

I takes about 3-5 secvs to start, turns over just fine.Runs great.

[Bob D.]

Did you check the fuel pressure?

[dksob81]

try turning the key to the ON position for 10 seconds, then off, then ON position again for 10 seconds, then try to start the jeep. Does it start right up?

[97JGC05]

Originally Posted by dksob81

try turning the key to the ON position for 10 seconds, then off, then ON position again for 10 seconds, then try to start the jeep. Does it start right up?

Yes it does after 10 secs in on it starts the 1st time I don't turn it off & on again for 10secs and start.. What does that mean?

[Bob D.]

Originally Posted by 97JGC05

Yes it does after 10 secs in on it starts the 1st time I don't turn it off & on again for 10secs and start.. What does that mean?

Fuel pressure falling after the engine is off.

[97JGC05]

Originally Posted by Bob D.

Fuel pressure falling after the engine is off.

Hi,
What needs to be replaced? Fuel pump?
Don

[Bob D.]

Originally Posted by 97JGC05

Hi,
What needs to be replaced? Fuel pump?
Don

Its difficult to isolate. Start by checking for proper pressure leak down at the fuel rail access port.
You will need a gage and have to know the proper method/specs to determine if the pressure is not holding or building properly. The only thing I could supply you with would be for a '99-2004. This is where a service manual comes in handy. Maybe someone here knows the specs for a '97.

[dksob81]

BOB is right.

Sounds like you FUEL PRESSURE REGULATOR is failing.
The Fuel Pressure for you ZJ should be 31-33 PSI. and it should increase approx. 8-10 PSI with the vacuum line for the FUEL PRESSURE REGUATOR disconnected.

The leak-down test for you ZJ (SUMMARY): Start the engine let it run for a minute or so with the pressure guage hooked up, shut the engine off (still leaving the pressure guage hooked up), take a note of the amount of pressure on the guage with engine off (will prolly drop down to around 28 PSI with the engine off) wait 30 minutes then record the ammount of pressure on the guage, if the pressure drops more then 10 PSI within 30 minutes after you shut off the engine, then the FUEL PRESSURE REGULATOR is bad.

[Dale Aeppli]

Originally Posted by 97JGC05

Hi,
What needs to be replaced? Fuel pump?
Don

Sounds like a bad pressure regulator. On 97's it is located on top of fuel pump assembly which is mounted in fuel tank. Regulator can be changed without removing fuel pump but, tank still must be dropped. There are two tabs that you compress to lift regulator from the fuel pump assembly. Dale [email protected]