I have a 92 Jeep Cherokee Country I just ran into a problem where it would start up and die right away. Now if I held the gas down at around 4 or 5 rpms she would run but die once it got down to 2 or so rpms. So I got it looked at and was told my fuel pump died because she would drop all pressure. I got it home and replaced the pump. Now it will run for about 10 or 20 secs before it dies. It sounds like it can not get any fuel now cause she chugs then dies. Ive also replaced the fuel filter to no change at all. Im clueless at the moment any help?
Cherokee Country Runs ruff then dies
- Thread starter Powerman
- Start date
MudderChuck
New member
I'd start with the easy stuff, normally when starting you shouldn't touch the gas pedal. The IAC is supposed to do all the work for you.
If the IAC is stuck closed, it can flood the motor. Try starting it with about 1/8-1/4 pedal, keep your RPM's up, then release the pedal. If it dies, it may be the IAC is stuck closed. You can also crank it a little with the throttle floored, this will shut off the injectors and purge the cylinders with air and may blow out some of the excess fuel.
I'm pretty sure the 92 is capable of storing trouble codes. Try the key method and see if you have any stored codes.
It will run really rich if the MAP sensor craps out, won't idle worth a darn.
A really poor idle, stalling and dieing can also be a sign of a failing CPS.
If it appears to be a sticky IAC ( which won't set any codes), spray some solvent in the IAC opening, then some spray oil. IAC can also start to act up when your battery gets weak, the IAC needs all the juice it can get to work well.
Of you get the IAC to working (motor idles), spray some solvent through the IAC opening in the TB, with the motor running, then some spray oil. It may take a few repeats over a couple of weeks, to get all the gunk out.
If it is the iAC, they often start working again after the motor is warm and the battery is filled up again after the start.
Just checked and if I understood correctly the MAP for the 92 is on the firewall???? If this is the case check the vacuum line from the TB to the MAP for rub through and make sure it is connected to the right outlet on the TB. The plastic vacuum line gets, way, brittle with age, you have to be careful. I remove them and visually inspect, especially along the bottom. The blow through them, then suck a little with your finger on the end, stop it with your tongue and see if it holds vacuum. On the earlier model XJ's it was possible to plug the MAP vacuum line into a dead end outlet, there are two, but only one goes all the way through (to vacuum). Not sure if the 92 has the same setup or not.
If the IAC is stuck closed, it can flood the motor. Try starting it with about 1/8-1/4 pedal, keep your RPM's up, then release the pedal. If it dies, it may be the IAC is stuck closed. You can also crank it a little with the throttle floored, this will shut off the injectors and purge the cylinders with air and may blow out some of the excess fuel.
I'm pretty sure the 92 is capable of storing trouble codes. Try the key method and see if you have any stored codes.
It will run really rich if the MAP sensor craps out, won't idle worth a darn.
A really poor idle, stalling and dieing can also be a sign of a failing CPS.
If it appears to be a sticky IAC ( which won't set any codes), spray some solvent in the IAC opening, then some spray oil. IAC can also start to act up when your battery gets weak, the IAC needs all the juice it can get to work well.
Of you get the IAC to working (motor idles), spray some solvent through the IAC opening in the TB, with the motor running, then some spray oil. It may take a few repeats over a couple of weeks, to get all the gunk out.
If it is the iAC, they often start working again after the motor is warm and the battery is filled up again after the start.
Just checked and if I understood correctly the MAP for the 92 is on the firewall???? If this is the case check the vacuum line from the TB to the MAP for rub through and make sure it is connected to the right outlet on the TB. The plastic vacuum line gets, way, brittle with age, you have to be careful. I remove them and visually inspect, especially along the bottom. The blow through them, then suck a little with your finger on the end, stop it with your tongue and see if it holds vacuum. On the earlier model XJ's it was possible to plug the MAP vacuum line into a dead end outlet, there are two, but only one goes all the way through (to vacuum). Not sure if the 92 has the same setup or not.
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FloridaCherokee1988
New member
X2, the IAC (Idler air control valve) was the 1st thing that came to mind for me too, possibly the TPS sensor too but usually they make the engine idle high when they start goin out. It doesn't idle high when it warms up does it?
So the iac looks fine after all. It idles fine warm or cold it just sounds like it runs out of gas now that the fuel pump got replaced. I am starting to think that something is blocking the fuel from somewhere. I got dont putting new fuel lines in when i did the pump and fuel filter. Any ideas what could be cloged up to stop flow of gas?
MudderChuck
New member
I'd get a fuel pressure tester, simple pressure gauge and hose that hooks up to the test nipple on the fuel rail. If the 92 is the same as my 88 the fuel pressure should be around 31 PSI with the fuel pressure regulator vacuum line hooked up and 39 PSI with the fuel pressure regulator vacuum line disconnected.
I had low fuel pressure once, it turned out to be crispy connector and the fuel pump was just fine.
The fuel pump should run for a few seconds when the key is turned to run, then it won't run again until the motor is cranked over. The computer needs a pulse signal from the CPS to close the fuel pump relay. The initial three second prime (timer) that happens when the key is turned to run doesn't last long and pressure falls quick, unless the computer gets a pulse from the CPS and closes the fuel pump relay and the pump runs continuously.
You can often loan out a fuel pressure tester from Auto Zone or other parts places. I use a freon F-12 test gauge (low pressure) to test my fuel pressure, same connections, works fine for me.
You can unhook the fuel line from the filter, plug off the tank side so it doesn't leak, and disconnect a fuel line from the fuel rail. You should be able to blow through there. You will likely blow some fuel out, so be careful. One of the fuel lines to the fuel rail is the feed line and the other is the return line and I can't really remember which is which.
I had low fuel pressure once, it turned out to be crispy connector and the fuel pump was just fine.
The fuel pump should run for a few seconds when the key is turned to run, then it won't run again until the motor is cranked over. The computer needs a pulse signal from the CPS to close the fuel pump relay. The initial three second prime (timer) that happens when the key is turned to run doesn't last long and pressure falls quick, unless the computer gets a pulse from the CPS and closes the fuel pump relay and the pump runs continuously.
You can often loan out a fuel pressure tester from Auto Zone or other parts places. I use a freon F-12 test gauge (low pressure) to test my fuel pressure, same connections, works fine for me.
You can unhook the fuel line from the filter, plug off the tank side so it doesn't leak, and disconnect a fuel line from the fuel rail. You should be able to blow through there. You will likely blow some fuel out, so be careful. One of the fuel lines to the fuel rail is the feed line and the other is the return line and I can't really remember which is which.
Did some more work tonight, I ended up testing the fuel pressure. When the key in turned to on the pressure builds to 39 or 40 then droped to 20 instantly then dwindles to zero. When I actualy run the moter it hits the 39 then goes down to nada. So i got a new fuel pressure regularor did nothing. Tried a new MAP also did nada. Any thing you guys can guess will help
MudderChuck
New member
I'd try to figure out if the electric or the pump is the problem. Figure out someplace to hook up a voltmeter and watch it when you turn the key to run, while your cranking and after it has started.
If you have a ballast resistor jump it, won't hurt a thing. Typical symptom is it will start, then die right away when the ballast resistor is bad. I don't have a wiring diagram of a 92, it may not have a ballast resistor or it may??
Farther down on my list of possible causes is a crispy connector. The power to the fuel pump goes through about 3 connectors, any of which may be cooking and causing grief. The fuel pump needs amps as well as volts. I had an 87 with low fuel pressure, it was a connector.
If you have a ballast resistor jump it, won't hurt a thing. Typical symptom is it will start, then die right away when the ballast resistor is bad. I don't have a wiring diagram of a 92, it may not have a ballast resistor or it may??
Farther down on my list of possible causes is a crispy connector. The power to the fuel pump goes through about 3 connectors, any of which may be cooking and causing grief. The fuel pump needs amps as well as volts. I had an 87 with low fuel pressure, it was a connector.
Hey so i got around today to pull out the pump and look over that and check the lines for any crushed lines. In the process I noticed I idioticly put the fuel filter backwards. Would that really cause a fuel pressure drop? I did have time to put it backin the pump that is and get more fuel but i will soon when i get some more free time. Just wondering if any of you could let me know in advance.
So I got the everything back in place and tested the return lines and what not by pinching them off to see if I would get a PSI build up. It ended up building more psi so I figured the lines were frozen but I have been letting it sit with a heater for about 5 hours and it runs better but still dies. So I am hopping now that all thats left to fix is some dang frozen lines. I had no idea that a frozen line would cause psi to drop till I looked at a repair book. This sound right to all of you.?
Glamissand1
New member
I feel your pain Powerman. I'm currently in the same boat hunting gremlins. I've got so far as to clean the idle up and revs and runs nice in park and neutral. But as soon as I go for a gear i sputters and dies. If it dosnt die right away any amount of pedal stalls it. New fuel pump, strainer, fuel filter, Ignition control module, coil, plugs, wires, cap, rotor, map, egr, and egr controler. CPS i have but due to rain its on pause. The symptoms did creep up on me, drivable to limpable, now i cant even get her in the garage.
Glamissand1
New member
Ground, it was a solder joint w/ most the upper sensors grounds where shorted where they spliced to one. Tucked up hidden in the wireing harness. Being rough in the area tryin to change out CPS caused the bad joint to finish breaking and pop out of harness. Plus side is, my girls got her mustard back.
Just can not figure this out. warmed up my lines even redid the pump. The new pump runs better and feels beeter build then the one I had but still will die out from a psi loss. Starting to look at electrical soon going to put in a new crank senser. The problem now sounds like something is making the pump not run after i start it up. Shop told me it should be the crank senser so ill be putting that in after the holidays but im not so sure i think its going to be a wire thats running the fuel pump relays charge. So anyone know were all the relays for the pump are? I found some relays behind the dash and under the hood any other places they could be hidding?
Glamissand1
New member
Id most definatly do the CPS, Just the condition of mine proved replacment. Comp needs a CPS signal to keep pumping. Nows a good time to go thru and clean all wire connectors (electric spray cleaner then dialectric grease). This also is water proofing. Have you checked the TPS for proper function? Clean up any grounds you can find, wire brush to clean metal and replace, then paint it.
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