cherokee re start issue..

Redriverranger · 11-25-2010, 05:12 AM

It does sound like a leaky injector, or the ect sensor is telling the computer it is cold all the time, effectively choking it. Were you checking the fuel pressure while you were having the issue? Or, it is not firing while you are trying to start it, and then finally when it does, it is flooded. Good luck. That really narrows it down....

humpy · 12-06-2010, 02:49 PM

figured it out....somethin about a heat soak in the #3 cylinder...common problem prior to 01 4.0 jeep engine....i guess the exhaust heats up the injector itself and ruins the injector...dealer sells a $10 shield to fix the problem...i think were gonna replace the injector and re seal them all and install the shield...and then...i get to do my bro in laws 2000 cherokee cause it has the same fn problem!!! thanks for all the input and hope our troubles may help someone else in the future...

humps823 · 03-08-2011, 09:37 PM

Hey, I'm the little brother in question. I let this go for a while, and have replaced everything above. I had a check engine light back a few months ago and had the codes run- it was a misfire cylinder #3: fuel issue. I did a little reading on this and apparently there ws some big heat soak issue that ruins the #3 injector. I have just recently replaced the #3 injector. It runs much smoother, but it still cranks forever. I had an exhaust leak before the 2nd O2 sensor, so I replaced the whole exhaust (converter had been cut on, so i replaced it as well). I am seriously stumped. I still think it is either choking or flooding itself, as I smell fuel in the exhaust at startup, and fuel mileage has decreased significantly. Before this issue started I could easily get 18.5-19.5 highway, and on a recent all speed limit trip to Michigan I barely broke 17.

I had been checking the fuel pressure while cranking. When I first turn the key I have ~46-52psi and it stays between there while cranking and running.

My next step will probably be to replace the Idle Air Control and clean out that area. This is only a hunch, and I don't think it'll work, because the high idle works at startup and my idle is pretty steady once it is up to temperature. I had read how to see if it is working once, I pulled it out and turned the key and it went in and out and adjusted itself, so I really don't believe it is the IAC, but I'm running out of options. It has stalled on me about 5 times, but only when sitting at a stoplight with it in Drive.

Any additional suggestions would be much appreciated!

Thanks

Black00XJ · 03-12-2011, 12:06 PM

I had thesame problem. Mine ended up being the temp. my motor would "over heat" after shut down and w/o enough time to cool, it would run in "limp" mode. I added a $30 thermostatic fan controler and $5 low temp thermostat and havent had this happen again... that was 6 years ago and she stills runs cool.

Black00XJ · 03-12-2011, 12:11 PM

Also, I wired my elec fan to run regardless of ignition being on or off. In the summer when its the hottest the fan will kick on about 5 times after shut down. I have never had a problem with a low battery either... Hope this helps. Ive know a few other guys with 00 & 01 XJ's that do this. They dont have enough air flow. My buddy fixed his by adding a cowl hood and the problem went away... I didnt have $550 plus shipping so I cheaped out lol.

humps823 · 03-19-2011, 07:05 PM

Quote:

Originally Posted by 8UP

The o-rings on the injectors were known to leak on the 4.0's. Look for fuel around the injectors.

Quote:

Originally Posted by Black00XJ

Also, I wired my elec fan to run regardless of ignition being on or off. In the summer when its the hottest the fan will kick on about 5 times after shut down. I have never had a problem with a low battery either... Hope this helps. Ive know a few other guys with 00 & 01 XJ's that do this. They dont have enough air flow. My buddy fixed his by adding a cowl hood and the problem went away... I didnt have $550 plus shipping so I cheaped out lol.

I put a 180 stat in and it doesn't seem to be running much lower... I could kick myself for not running the 160 now, but I was afraid it would make it want to dump more fuel to bring temperature up. I'm gonna throw one in to see what it does, as I'm still running around 190-195 moving, and close to 200 idling. radiator has been thoroughly flushed several times and the mechanical fan is good. I also wired in that thermostatic controller, and it seems to kick on around 170. Wired it straight to battery, and it cycles 3-4 times after shutoff. also no problems with battery, as i actually was sittin listening to stereo for 4 hours after it did its cycles and it still cranked well.

I also replaced all injector o-rings when I replaced the #3 injector. There didn't seem to be any leaks before or after this.

itbrokeagain · 03-12-2011, 01:54 PM

Quote:

Originally Posted by humps823

I had been checking the fuel pressure while cranking. When I first turn the key I have ~46-52psi and it stays between there while cranking and running.

Fuel pressure seems a little high. I believe 40 is the number you want. I know that is what a 4.0 Yj needs.

8UP · 03-14-2011, 10:09 PM

The o-rings on the injectors were known to leak on the 4.0's. Look for fuel around the injectors.

humps823 · 03-19-2011, 07:08 PM

Quote:

Originally Posted by itbrokeagain

Fuel pressure seems a little high. I believe 40 is the number you want. I know that is what a 4.0 Yj needs.

What regulates the pressure on these? I'm afraid you're going to tell me it's in the tank... I'm getting to know my jeep better and better every week, even more than I'd like to, ha!

humps823 · 03-19-2011, 07:21 PM

One thing I forgot to mention... Someone had tried to cut my cats out last fall, but I guess someone spooked them and they left the job unfinished (half-asses). I crap-welded it back together in a hurry, but they had cut before the 2nd O2 sensor, and it leaked a little. Now I've put in a new cat and exhaust, but is it possible the computer calculated for the leak and never reverted to what it should be? It's a long shot but I wanted to make sure I mentioned that.

humps823 · 03-19-2011, 07:29 PM

Quote:

Originally Posted by Redriverranger

It does sound like a leaky injector, or the ect sensor is telling the computer it is cold all the time, effectively choking it. Were you checking the fuel pressure while you were having the issue? Or, it is not firing while you are trying to start it, and then finally when it does, it is flooded. Good luck. That really narrows it down....

whoops, didn't see this one. yep, I was checking the fuel pressure and it read between 46-52 pounds, which another member said might be too high.

I put a coil on it as well, so I'm hoping it's not an issue with firing. It runs fine after it runs about 30 seconds, but it seems to be drinking a little extra fuel.

What is the ect sensor and where is it? How does one test that sensor?

thanks!

humps823 · 03-19-2011, 09:57 PM

I got it! I found a listing of what the coolant temp and ambient temp resistance readings are supposed to be, and since i'd already replaced the coolant temp sensor (with no change), I did a reading on the ambient air (or air charge, or MAT, there were several names for it), and got a reading of 5k ohm at 92 degrees. It should have read ~2200 ohm (colder temps yield higher resistances) I calculated this, and a couple other tests, to be off (low) by about 32-37 degrees F, depending on the temperature. Bought a new one at advance (P# WT2000) for $23.49, and she starts right up now!

The info for the resistance readings came from here

Hopefully this info saves somebody else a lot of time and money! Test $25 sensors and replace before buyin $100 coils and $50 injectors haha.

11-25-2010, 05:12 AM	#1
Redriverranger White ranger guy Join Date: Nov 2007 Location: Red river gorge,ky Posts: 274	It does sound like a leaky injector, or the ect sensor is telling the computer it is cold all the time, effectively choking it. Were you checking the fuel pressure while you were having the issue? Or, it is not firing while you are trying to start it, and then finally when it does, it is flooded. Good luck. That really narrows it down.... __________________ 91 Ranger ext cab, 60, 14 bolt, 4:88's, 39.5's, doubler, lot's of character

03-19-2011, 07:21 PM	#10
humps823 Join Date: Dec 2010 Posts: 6	One last possibility One thing I forgot to mention... Someone had tried to cut my cats out last fall, but I guess someone spooked them and they left the job unfinished (half-asses). I crap-welded it back together in a hurry, but they had cut before the 2nd O2 sensor, and it leaked a little. Now I've put in a new cat and exhaust, but is it possible the computer calculated for the leak and never reverted to what it should be? It's a long shot but I wanted to make sure I mentioned that.

03-19-2011, 09:57 PM	#12
humps823 Join Date: Dec 2010 Posts: 6	Apologies for the overpost, but it's fixed! I got it! I found a listing of what the coolant temp and ambient temp resistance readings are supposed to be, and since i'd already replaced the coolant temp sensor (with no change), I did a reading on the ambient air (or air charge, or MAT, there were several names for it), and got a reading of 5k ohm at 92 degrees. It should have read ~2200 ohm (colder temps yield higher resistances) I calculated this, and a couple other tests, to be off (low) by about 32-37 degrees F, depending on the temperature. Bought a new one at advance (P# WT2000) for $23.49, and she starts right up now! The info for the resistance readings came from here Hopefully this info saves somebody else a lot of time and money! Test $25 sensors and replace before buyin $100 coils and $50 injectors haha. Last edited by humps823; 03-19-2011 at 09:58 PM. Reason: crappy grammar

12-06-2010, 02:49 PM	#2
humpy Join Date: Sep 2008 Posts: 573	figured it out....somethin about a heat soak in the #3 cylinder...common problem prior to 01 4.0 jeep engine....i guess the exhaust heats up the injector itself and ruins the injector...dealer sells a $10 shield to fix the problem...i think were gonna replace the injector and re seal them all and install the shield...and then...i get to do my bro in laws 2000 cherokee cause it has the same fn problem!!! thanks for all the input and hope our troubles may help someone else in the future...

03-08-2011, 09:37 PM	#3
humps823 Join Date: Dec 2010 Posts: 6	Heat soak in #3 was not the issue Hey, I'm the little brother in question. I let this go for a while, and have replaced everything above. I had a check engine light back a few months ago and had the codes run- it was a misfire cylinder #3: fuel issue. I did a little reading on this and apparently there ws some big heat soak issue that ruins the #3 injector. I have just recently replaced the #3 injector. It runs much smoother, but it still cranks forever. I had an exhaust leak before the 2nd O2 sensor, so I replaced the whole exhaust (converter had been cut on, so i replaced it as well). I am seriously stumped. I still think it is either choking or flooding itself, as I smell fuel in the exhaust at startup, and fuel mileage has decreased significantly. Before this issue started I could easily get 18.5-19.5 highway, and on a recent all speed limit trip to Michigan I barely broke 17. I had been checking the fuel pressure while cranking. When I first turn the key I have ~46-52psi and it stays between there while cranking and running. My next step will probably be to replace the Idle Air Control and clean out that area. This is only a hunch, and I don't think it'll work, because the high idle works at startup and my idle is pretty steady once it is up to temperature. I had read how to see if it is working once, I pulled it out and turned the key and it went in and out and adjusted itself, so I really don't believe it is the IAC, but I'm running out of options. It has stalled on me about 5 times, but only when sitting at a stoplight with it in Drive. Any additional suggestions would be much appreciated! Thanks

03-12-2011, 12:06 PM	#4
Black00XJ Join Date: Feb 2011 Location: dont ask Posts: 18	I had thesame problem. Mine ended up being the temp. my motor would "over heat" after shut down and w/o enough time to cool, it would run in "limp" mode. I added a $30 thermostatic fan controler and $5 low temp thermostat and havent had this happen again... that was 6 years ago and she stills runs cool.

03-12-2011, 12:11 PM	#5
Black00XJ Join Date: Feb 2011 Location: dont ask Posts: 18	Also, I wired my elec fan to run regardless of ignition being on or off. In the summer when its the hottest the fan will kick on about 5 times after shut down. I have never had a problem with a low battery either... Hope this helps. Ive know a few other guys with 00 & 01 XJ's that do this. They dont have enough air flow. My buddy fixed his by adding a cowl hood and the problem went away... I didnt have $550 plus shipping so I cheaped out lol.

03-14-2011, 10:09 PM	#8
8UP Join Date: Oct 2008 Location: 1 Posts: 92	The o-rings on the injectors were known to leak on the 4.0's. Look for fuel around the injectors.