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Wont start; Rough Idle and then stalls when it does start

M

MudslinginXJ

NAXJA Forum User
Location
Pennsylvania
I've got a 92 Jeep Cherokee Automatic 6 cylinder and i have been happy with the way the jeep has been performing for the last couple months and everything seemed fine til a couple weeks ago when i was leaving for work and it didn't run all weekend. When i started it up it had a rough idle for a couple seconds, i gave it some gas and it cleared up. I thought all was well. This happened maybe once or twice. After coming home from work to day (no flaws at all, running fine) i let it sit. My dad took my jeep to go pick up my sister and said whenever he went to start it, it took longer then usual. I know jeeps are notorious for long starts, but this was good 5 seconds longer then usual. I get in it to run to the store and it again takes longer then usual to start. As soon as i get off of my street, i go to give it some gas and notice there isn't any response. I see idiot light come on for the oil. I coast to the side of the road and see if the computer would spit a code, but nothing, just 55.


There is definetly spark, and fuel because it was turn over and sputter, sometimes start and run for a couple seconds but as if it was only firing on a couple cylinders. What do you think it could be? I just replaced the CPS not even 2000 miles ago, the o2 sensor was changed. There is fuel at the rail, as well as spark. My father seems to think that it is dirty injectors. Is there anything i can check and try so i can get this thing running? Where would be a good place to start?
 
Since i cant edit to make my last post easier to read i'll just repost.

After a couple days of sitting the jeep would start up normally but have a rougher then usual idle. That would go away with giving it a little gas and then everything was fine. The jeep took awhile to start yesterday, more then the usual long jeep start time. It stalled while at the bottom of my hill. I coasted it to a flat spot, let it sit and tried to start. It would crank over and sputter and try to start but there was nothin there. Eventually when it did start it sounded like as if it was only firing on a couple cylinders and would die after a couple seconds. I have replaced the CPS and o2 sensor already when couldn't get it to start before. Also replaced the coil.

What do you think it could be? BTW its a 92 6cylinder aw4.
 
Try just turning your key to the 'on' position, but not cranking the engine. leave it there for 30 seconds, then try to start it. Try pumping your gas a few times during that period. If the jeep starts then, but dies when you try to put it into drive/reverse, I'd say you have fuel pump/filter problems. This sounds like what mine did when I got it until I replaced the pump.

You can have pressure at the rail, but without a pressure gage you can't tell whether it's getting the correct amount of pressure from the pump.
 
A couple of months back the wifes 96 was hard starting, I´d have to start it, with about 1/4 pedal, it normally started right up with no pedal. I did get a MAP code once, but it didn´t repeat and it was still hard starting. It would start somewhat better when it was hot, but idled low and rough.
The problem turned out to be, a sticky IAC, that would only (usually) stick when the motor was cold. Cleaned and oiled the IAC and it´s been going for a couple of months without a hiccup. I still have no idea why the MAP coded, can´t really remember if it was a 13 or 14, but it never did repeat.
 
If i were to pump the gas pedal a 4-5 times and then try to start it, sometimes it would fire up, stay running for a couple seconds and then die. Or it would just continue to try and fire and get close to running, but never actually idle or anyting.
 
just went out and turn the key to the on position and kept it there until the fuel pump stopped priming. Turned the key off, and repeated until it wouldn't prime anymore. Turned it over and it would start but wouldn't stay running. Almost as if the fuel pump was bad. Gonna go buy a fuel pressure gauge to check the pressure at the rail. Can i check it without the jeep running? If not then im kinda screwed:hang:. Although, if i can test it without the jeep running, can anyone give me some instructions or at least what the fuel pressure should be so i can declare this pump dead or alive?
 
Replaced the MAP Sensor, that wasn't it. So now before i rip into the tank, im going to replace the fuel filter just to make sure that isn't it, and it could probably use a new one since its a 92. Hopefully by this weekend i'll have it running. I'll keep you posted. Also if there is anything else you can think of to try, let me know.


If i do have to replace the fuel pump what brand should i replace it with. Is the Airtex Fuel Pump Assembly from Rockauto.com any good?
 
Last edited:
MudslinginXJ said:
just went out and turn the key to the on position and kept it there until the fuel pump stopped priming. Turned the key off, and repeated until it wouldn't prime anymore. Turned it over and it would start but wouldn't stay running. Almost as if the fuel pump was bad. Gonna go buy a fuel pressure gauge to check the pressure at the rail. Can i check it without the jeep running? If not then im kinda screwed:hang:. Although, if i can test it without the jeep running, can anyone give me some instructions or at least what the fuel pressure should be so i can declare this pump dead or alive?
Click to expand...

Hallo Mine 92 had a problem with condenswater in the fueltank (tank was almost empty). Mayby you have to check your Ballast Resistor also.
I have ordered a fuel pressure gauge by Ebay (Actron CP78818). I hope that they sent it quick to Holland Europe. Pressure is there without starting the engine, only turn the key on. 39 PSI is normal. Test for the pressur regulator, is only possible with the engine starting. (Vacuum line attached 31 PSI,detached 39 PSI. Good Luck:wave1:
 
Hey mine is doing the same thing. It has me baffled. It starts up just fine if it has been sitting for an hour or longer but if you drive to the store (for example) and shut the jeep down come back out 15 minutes later it will start right up,throw the check engine light, and as soon as I put it into 1st, or reverse it just freakin dies. I then have to wait for 40 minutes or longer before it will start and drive again. I replaced MAP and TPS with no improvement. How does one bypass the fuel pump shutoff switch?
 
xylonjay said:
Hey mine is doing the same thing. It has me baffled. It starts up just fine if it has been sitting for an hour or longer but if you drive to the store (for example) and shut the jeep down come back out 15 minutes later it will start right up,throw the check engine light, and as soon as I put it into 1st, or reverse it just freakin dies. I then have to wait for 40 minutes or longer before it will start and drive again. I replaced MAP and TPS with no improvement. How does one bypass the fuel pump shutoff switch?
Click to expand...

i dont believe there is a fuel cutoff switch.

how about retrieving the codes? what year?
 
:guitar: Thanks for the link. Well after reading ALOT about my possible options, Ive narrowed it down to a bad Coolant Temp Sensor. Last night on my way to go ice fishing, my girlfriend need to stop by the store and I had to wait outside with the truck running. Well, eight minutes passed and the XJ choked and died. I could start as usual with no issues, but trying to drive away was a different story. I then had an idea. After reading about the coolant temp sensor, I decided to try and cool of the sensor by applying a dirty, crusty, piece of snow I broke off of a snowbank, and applied it right to the sensor. After 5 minutes I was back on my way. XJ fired right up and no check engine light came on. I am going to replace it this weekend and hope it works ***fingers crossed*** Thanks again everyone and i'll report my success or failure.
 
Okay, im having similar issues. My battery died (left dome light on over night). so i jump started it. It did not want to start at all. but if u jus barely touched the gas pedal it would start, as soon as you let off it died, after about 5-10 minutes it would finaly idol by its self but still rough, the check engine light is now on and i woke up to coolant all over my garage floor... ideas? 1997 5sp 80k 4.0
 
I would do a tune up. Replace cap, rotor, wires and distributor possibly even replace your TPS. Other than that Ive got nothing for ya. I still havent got my issue stated above resolved. Im bummed, im currently looking for a new XJ
 
My 96 Jeep Grand Cherokee 4.0, hyas started giving me some problems.
At times it run fine, then without warning it would start sputtering, backfiring, and stalling. Initially when it stalled it would start right up, but now it is requiring several attempts before it does. It has been stalling at lights, even when I am just driving I would notice the depletion in power, which ultimately results in it stopping.
 
First thing would be to replace fuel filter if it's been a while. They are cheap. How many miles are on the current one? Second thing I would do is to get fuel pressure readings at the fuel rail as it sounds like you are planning on. Simple things first; you have to start the process of elimination and testing is cheaper than throwing parts at it. This could be as simple as a weak fuel pump.

If fuel pressure checks out, two sensors that I'd check into would be the TPS and the IAC
 
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