Last post on Dec 10, 2013 at 2:04 PM
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Jeep Grand Cherokee
#1011 of 1241 Re: 1995 Jeep Grand Cherokee Laredo. Please Help. Tried everything. [swelms]
Jul 15, 2012 (8:23 pm)
I have the exact same problem as Swelms. I own a 1998 Jeep Grand Cherokee Laredo and if I have been driving for a long time, the power just dies. The speedometer goes down and the rpm drops from 3000 to 1000. If I give more gas, than the car brakes.
I usually let go of the gaspedal for a few seconds and then I can drive again, but this only resolves the problem for a little bit and eventually I need to give my car a rest for about 20 to 30 minutes and then it is fine again.
I asked a few mechanics and even in a Jeep garage, nobody had ever heard of this problem. So I really hope somebody can give me an idea what the problem is and how to fix it?
Thank you soooo much!!!
#1012 of 1241 grand cherokee wont start
Jul 21, 2012 (10:55 am)
I have an 02 grand cherokee (v8) when driving home i thought i felt a misfire but got home without a continuing problem. when i went to start it the next day it cranked but wouldn't start. the codes that i found ( 7 of them) were po455 ,po171. po174,po442.po158,po161, and po0300 i can relate there discriptions if needed but they are basically evap leak large , o2 sensor 2 on bank 2 heater and high voltage, random misfire and bank 1 and 2 lean. the light of course had come on but it ran great until i felt the misfire. any help on where to start would be greatly appreciated
#1013 of 1241 Re: 1995 Jeep Grand Cherokee Laredo. Please Help. Tried everything. [ellies_rocket]
Jul 23, 2012 (3:28 am)
I would recommend to check up the heated wire sensor in the air intake. The wire sensor is very often dirty by the air deposits - grease dust etc. It makes a signal distortion and possible control problems.
The cleaning is very simple, only be careful not to damage the wire.
#1014 of 1241 Re: grand cherokee wont start [ralka]
Jul 23, 2012 (3:45 am)
by my experience it runs as follows:
- the bank 2 O2 upstream sensor is bad - trouble codes P0158 - P0174. It costs a few bucks only
- the unevitable misfires follow - P0300
- after that goes too much unburned fuel to the charcoal cannister, that cannot to process it - code P0442.
Have the upstream O2 sensor checked and replaced, then deleted the DTCs.
I hope it helps
#1015 of 1241 Re: grand cherokee wont start [danny80]
Jul 23, 2012 (10:25 am)
thanks for the insight, i will replace the o2 sensor first and see where that leads. i will let you know if that works
thanks again for the help
#1016 of 1241 Re: grand cherokee wont start [ralka]
Jul 24, 2012 (3:36 am)
I wonder if it comes right.
I may only have been wrong in one thing: the EVAP cannister absorbes fuel vapours from the tank primarily. But is connected to the PCV valve, there could be a little bit unburned fuel which makes problem for the emission control system.
I think faulty O2 sensor is essential.
#1018 of 1241 Re: 98 Jeep Grand Cherokee Laredo issues [annoyedwmyjeep]
Jul 30, 2012 (4:28 am)
Here's my suggestion for this problem. I am posting this solution in various places because there are many forums and this problem seems to be widespread.
About a year ago, my 97 GC started with the stalling problem. I have replaced everything that everyone talks about ...It is a complete shutdown of ignition....Code readers say that it is the ignition coil, or ignition coil signal. It is also very random....and not necessarily heat related. Sometimes, the vehicle won't start after sitting all night....sometimes it will stall when backing out of the driveway....sometimes after 10 minutes of driving....sometimes not at all for a trip to the store, but then stall several times coming home from the store. One thing is for sure….it gets worse and worse as time goes on.
Sometimes, it helps to disconnect the battery....sometimes, it doesn't. There are times when it refuses to restart, and then unplugging and replugging various sensors helps. Sometimes, it helps to reseat the PCM connectors....and then sometimes it doesn't.
Well....I've been through all the replacement stuff...I've traversed the awful sensation of the car stopping suddenly while I'm in the center lane during rush hour....I've experienced the horror of stalling in the middle of an intersection, and the frustration of not getting to work on time.
Oh baby...I know this problem...and I am a long-time veteran of electronic circuitry. I am a component-level troubleshooter, and I was not about to allow this problem to win the day.
Unfortunately...this problem is allusive in it's randomness....and also by the pesky disappearance when you replace a sensor....then it rears its ugly head a few days later. So......after $500-$1000 worth of component changing...you are left with the same problem and a box of used parts that probably were never bad to begin with.
So....On to the solution. Now, one person on another forum suggests shortening the length of the PCM cover screws a bit. I’m not convinced that this does anything…but it seemed to work for him.
Nevertheless....I was willing to shorten up those screws, simply because it doesn't hurt to give it a try. There's no doubt that the problem rests in the PCM Connector configuration. Whether it is dirt, corrosion, or poor intimate contact....the problem is there.
I've noted that several people claim success using zip ties on the connectors, and while this may work, I am uncomfortable with the use of zip ties because they put stress on connectors in weird directions....the problem may return over time.
I was convinced that the solution rests in ensuring a zero-vibration environment at the connector. But the connectors needed to be seated firmly and perfectly perpendicular to the surface of the PCM.
The screws? well, they might play a part in all this, but I could see nothing down in the screw holes that would suggest a short circuit with a circuit board component....it is just an empty hole. The screws could be corroded, and not making good contact...but if you remove the screws completely, the symptoms don't change. Sooo I'm skeptical.
So, I ran into a forum post elsewhere that describes this same problem, and the creation of a connector bracket. This sounded perfect. So I made one. It cost me $6.43 for the materials...it took 15 minutes to make the bracket....and 45 minutes to install.....and my stalling problem is gone.
Very simple. Go to Home Depot....buy the following junk:
1 - 36" Steel Bar 1" wide X 1/8" thick
2 Bolts 4" long X 1/4
2 Wingnuts (1/4")">
From the steel bar, using a hacksaw, cut off 2 lengths of bar 9" long each.
Drill holes large enough for the bolts on both ends of the bars
One bar goes behind the PCM
One bar goes on top of the connectors
Use the wingnuts to tighten the connectors firmly into place.
Remove your battery cables and short them together (use a wrench or screwdriver)
Remove the coolant overflow tank hose...set aside (1 minute)
Remove three coolant overflow tank mounting screws (5 minutes)
Remove coolant overflow tank (1 minute)
Remove PCM Connectors from PCM (1 minute)
Remove 3 PCM Mounting bolts (5 minutes)
Remove PCM (30 seconds)
Remove screws from front plate of PCM and grind them shorter or replace them with shorter screws (just in case)(5 minutes)
Place one bar on backside of PCM...Place other bar on front...then wingnut them in place from the front(this is just to get the bracket in place because you can't put the bolts on while the PCM is still mounted on the firewall) (2 minutes)
Now Mount the PCM back onto the firewall (5 minutes)
Loosen the wingnuts out to the end of the bolts....Install the connectors....tighten down the wingnuts with great zeal, but not so much as to distort the bar very much. (there will be some bow in the bar...but don't sweat it)(5 minutes)
Now reinstall your Overflow coolant tank (5 minutes)
Reconnect your battery (2 minutes)
Start Car and Drive away.
Stop Car..get out....close hood...Now drive away
#1019 of 1241 Re: grand cherokee wont start [danny80]
Jul 30, 2012 (11:56 am)
i had a chance to look at the jeep (02 jgc 4.7) today, and found that there is no fuel getting to the throttle body. i than shot some 2
+2 down and it did run briefly, i than pulled the fuel filter/regulator above the rear differential and pulled one of the lines going to the tank and cycled the ignition to see if any fuel exited the line (none). i am thinking fuel pump but i do hear what sounds like the pump starting when the key is turned. does anyone know if the pump can be running if it is bad and is there anything else that will stop fuel pressure to the engine?
#1020 of 1241 Re: 2002 Jeep Grand Cherokee laredo problems [alby3]
Jul 30, 2012 (12:10 pm)
Hope the oil sending unit was your problem. I had the same problem but it turned out to be much more extensive. Not trying to scare you. I had about 210K on the original engine. Apparently the engine bearings get out of shape and when the engine warms up the oil pressure drops. I replaced the oil pump and tried a more viscous oil which helped a little. Drove the engine for another year or so until I finally ended up with a hole in a piston from lack of lubrication. I replaced the engine myself but it was still $2k. Good luck and I hope it's minor.