Jeep keeps stalling , need help

Jake31011 · #1 05-26-2013, 03:04 PM

So i have a 1999 Jeep Grand Cherokee Laredo, 4.7L v8 , it has been running good until as of lately. It has stalled or died on me 3 times , i can usually drive it for about 20 minutes, or travel short distances before it stalls out on me, the stalling is completely random, any speed/RPM. i have read everything under the sun about what could be wrong here, i have no idea where to start, have been hearing alot about new Crankshaft sensors, TPS's , etc etc so any help would be appreciated, thanks.

SleepyHead98 · #2 05-26-2013, 04:14 PM

Hey Jake, we spoke in the chat room. If your check engine light is on, get those codes read and let us know which ones where showing. You can get them read at Advance Auto Auto Zone, and I think Orielly's. Not sure if you have any other parts stores where you live but that's whats around where I live.

Jake31011 · #3 05-28-2013, 07:42 PM

Hey again, sorry it took me so long to get back to you, i got a code reader and i used it on my jeep, gave me 0 codes. Note that the check engine light only comes on when it stalls, do i need to stall it to find out?

hundahunta · #4 05-30-2013, 01:37 AM

I would try a cam and crank sensor. Depends on how the sensor fails it may not throw a code. I have also seen bad pcm's do this but the only was to verify it would be with the drb. Does the engine light come on then the vehicle stall or does the engine light come on because the vehicle is not running and has stalled.

SleepyHead98 · #5 05-30-2013, 07:38 PM

Check your fuel pressure. Pump might be getting worn out. Fuel filter, might have never been changed. Since you dont have codes, most probably not a sensor but you never know.

Jake31011 · #6 06-03-2013, 11:26 AM

Thank you guys for your help, i took my jeep in to a mechanic, they said they couldn't stall it so they could not get any codes, and when its not stalled i don't get any codes, all they had to tell me was that on their gauges my fuel pump was " fluctuating " or was not a stable and consistant flow, does that mean i need to replace it? thanks

Jake31011 · #7 06-12-2013, 04:41 PM

Took my jeep in and got my fuel pump replaced, and bam, stalled again, i dont know where to go from here.

autojoe · #8 06-12-2013, 07:10 PM

when it stalls will it restart?long crank time?
( they said they couldn't stall it so they could not get any codes....that is so stupid for a mechanic to say that..........stalling would have nothing to do with codes stored in memory......if the pcm detects a problem it will store a code in memory.you have to find out if you are losing spark.....fuel pressure.....injection pulses.

SleepyHead98 · #9 06-12-2013, 08:54 PM

Look into all the causes of fluctuating fuel pressure. Maybe fuel pump relay? Does the Jeep smell like gas? Perhaps there is a leak somehwhere. Look a the fuel pressure check valve, is that up to snuff? Any liquid? Follow the electrical lines from fuel pump to computer, are there any cuts or anything? Find out exactly how many volts are reaching the fuel pump (and verify that these are the right amount of volts needed to power the pump), and check and make sure that the ground to the pump is perfect. For these last two, volts and Ohms, you will need a multimeter, Harbour freight sells them on the cheap, and most probably you will need to know which one is voltage, and which one is ground on the wires themselves.

autojoe · #10 06-12-2013, 10:11 PM

if mechanic said...they said they couldn't stall it so they could not get any codes.would you trust the rest.Without proper diagnostic equipment it is hard to diagnose problem.why would someone replace fuel pump without testing and proving it was bad.......parts changer?take to a shop that specializes in vehicle diagnostics preferrably ase certified.A good shop would do pressure and volume testing.then may have to current ramp fuel pump/voltage and ground testing.

Jake31011 · #11 06-27-2013, 10:49 PM

Sorry i have been gone so long, anyways after the fuel pump failed to fix, i replaced the crankshaft position sensor, and it fixed it!...for about 5 days, and then it stalled out on me again, this time it only took about 25 mins to restart rather than an hour, so confused, i said screw it and decided to take it to a professional. took it to a jeep dealership, which charged me $130 for a diagnostics and inspection to find the issue. They called me and told me that my car battery and battery harness is causing the problem and that i should replace them both. To me that didn't sound quite right, im no pro, but i told a few friends about the progress, which they responded that that's not the issue.... i'm stumped. any advice? ( thanks again everyone for your help i really appreciate it )

autojoe · #12 06-28-2013, 07:48 AM

ask the jeep dealership if they will stand behind their work and guarantee to be the problem and get it in writing.it would have to be tested during problem.did they say if they could duplicate the problem and test while problem was showing?Did they actually see problem or just guessing what the problem is.ask them these questions to service manager.did the battery fail a load test?a wiring issue makes sense since your problem is not consistent.see what they say.

Jake31011 · #13 06-29-2013, 07:46 PM

The service management is closed until monday, i will call them then, but they told me that they did in fact get it to stall , that is all i know, i will call them monday to ask them the questions.

SleepyHead98 · #14 07-03-2013, 11:07 PM

In a way, it makes sense, Completely random, guys couldnt get it to stall at shop, everything else seems to be in order. Hit a bump and lose battery power, the ECM will lose power and shut down. Makes sense to me. Keep us posted.

Jake31011 · #15 07-07-2013, 01:57 AM

Alrighty,so the update now is that i took it to sears, and asked them to do an alternator check, so they tried and told me that they can't because my battery was bad ( not according to jeep ) so i bought a new car battery, and the one they put in is much bigger than the one before, they then told me my alternator is good. also, my brakes were shot to shit so a buddy and i replaced all my pads and rotors, on the way back, sure enough, the jeep stalled, except much differently this time. usually it stalls, powered steering goes off and all my gauges dropped, then would take about an hour to start, well this time it stalled at a red light, steering went off but all my gauges stayed up. so i turned it off and back on and walla it started right back up. so we are getting somewhere.

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