My pump went out so I put a used pump and tank combo. The jeep it came out had a maintenance record of a new pump within 700mi. But I have longer starts and when I shut it off i can here alot of gurgling. Is this just the return line? Have not presser checked it yet.

 

If it helps its a 99 sport 4.0

 

weird, sounds like a check valve issue.
i remember an old thread about using an inline BMW check valve. you can try that.

here is the thread.
https://www.cherokeeforum.com/f2/fue...k-valve-21921/

 

Pressure testing with a gauge is really needed here...........

Looking for 49 psi at idle plus or minus 5 psi to verify the pump.

Also want to be sure that the spec for "pressure drop" after the engine is turned off is correct. Otherwise, yes...checkvalve is suspect.

 

Don't forget to disconnect and cap the vacuum line between the intake manifold and fuel pressure regulator. :-)

 

the 99-01 cherokees had extremely common issues with the check valve in the fuel pump. Your longer starts and "gurgling" point straight to that issue.


The fuel pump check valve is supposed to hold pressure in the fuel line while the engine is off. The check valve is located on the fuel pump and located in the gas tank. A failed check valve allows the fuel to drain back to the tank. This results in the following symptoms:

SYMPTOMS

· Longer than normal cranking times
· Never starts on first try, almost always starts on the second try
· Rough idle for a few moments of idling
· Rough running for first ½ block of driving
· Little or no fuel pressure at the fuel rail test valve similar to this -

1- Key in on position; fuel pump primes for 2 seconds then stops. 0 PSI
2- Cranking over the engine. 2-3 PSI
3- Engine starts and idles for 20 seconds. < 5 PSI
4- Engine idles and fuel pressure creeps up to 45 PSI.


POSSIBLE CAUSES

· Failed check valve on the fuel pump in the gas tank.
· Leaky fuel injector(s) may be the true cause of your problem, but more likely they are simply contributing to the check valve issue.

Testing of the fuel injectors should show if any are faulty and are allowing fuel to drain into the cylinder. Either problem can allow heat soak to vaporize the remaining fuel in the fuel rail and you may be dealing with a bit of vapor lock as well, especially in warmer weather.

1. Connect the gage at the fuel rail and start the engine. The gage should read 49 psi plus or minus 2 psi.

2. Turn the engine off and immediately clamp the fuel line just ahead of the fuel tank. Watch the pressure gage and see how long it takes to loose pressure.

If the pressure remains at 49 psi for an extended period of time then the problem is in the tank - probably the check valve. If the pressure falls below 49 psi fairly rapidly then the problem is probably a leaky injector.

There are a few solutions to the problem –

1. Turn the key to ON for 5 seconds and let the fuel pump prime. Turn the key to OFF, turn the key back to ON for 5 seconds, start the engine.

2. Crank the engine for 3-5 seconds, pause, and crank the engine again. It will almost always start on the second try.

3. Replace the fuel pump assembly in the gas tank. The check valve is not a separate part and cannot be serviced. This is both expensive and time consuming because you have to remove any hitches and skid plates and then remove the gas tank from the vehicle.

You can use solutions 1 or 2 for as long as you want to, they do not harm anything and the fuel pump will continue to function for many more years.

 

Sounds like what I got going on for sure! It will have to hold off till next weekend unfortunately. Have to help a local with a new drag link set up and hopefully sell my 95er.

 

that's why i was saying to install an inline check valve. it doesn't matter if the one on the fuel pump is shot.

or, yeah, you can just do 1 and 2 for as long as you need.
the wifey's tj is like this, and has been for over a year. gets kinda old tho, but problem is only in the morning, first start. then starts fine all day.