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99 Grand Cherokee Laredo 4.0 In-Line 6. Problems

 
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dumpsterdom89 dumpsterdom89
New User | Posts: 12 | Joined: 04/12
Posted: 04/14/12
03:52 PM

Hey all. My jeep is awesome. I've had it for six years and the problems I am about to discuss have been occurring throughout. Only now they seem to be getting worse. Firstly, upon starting and letting idle, the engine hesitates and stutters. I very noticeable amount of water is spurted from the exhaust (thermostat?).  Once I put it in gear to drive the car will operate fine in low rpms. When I try to accelerate, the engine hesitates and almost stalls even with the gas peddle pushed down.  This is followed by a few loud clunks and the motor revs up to the rpm that matches where the peddle is. At low speeds, this goes on forever. When I give it gas, the problems happens a few times, then the motor revs up and I'm off. I have a California emissions package, though I live in PA...the sensors do need replaced. Oh and the motor does not misfire when in neutral for some reason...I am thinking of doing an overhaul on the sensors, throttle body positioner, and possibly gas tank/fuel filter.

Am I missing something here?

Thanks  

waynep71222 waynep71222
Guru | Posts: 825 | Joined: 03/12
Posted: 04/14/12
04:45 PM

this is a hard one to diagnose...

lets start and see if there are any codes stored...  with the key in the ON position.. not running..   flip the key off.. ON.. off.. ON .. off..  ON..  off     ON... with the final position in the ON position...

at that point.. if you have a digital odometer.. it should start flashing codes at you .. write down the whole numbers..

post them...

have you gotten the jeep deep into water.. or mud???   or splashed really hard .. where it coated the engine completely??

is there an exhaust leak from the header???? where it is cracked down near the collector..   if so.. it can be removed and welded .. i normally take them off and drive the header over to the muffler shop.. where they are really good at wire feed welding the exhaust type of materials..  the cracks are usually in a place where is cannot easily be welded on the jeep..  

you do have to pull the intake to do this..   not a huge problem.. except for the need of the slip tool to disconnect the fuel line from the fuel rail..  do remove the oxygen sensor before having it welded..  why.. leaks into the exhaust make the computer crazy as it sees extra oxygen and tries to adjust the fuel injection to get rid of it..

while you are under the jeep... look for the ground connections on both sides of the engine block.. down near the bell housing..   take them apart and wire brush the ring terminals..  wire brush the stud and the nut.. put it back together..

ca you see if the small vacuum hose from the PCV valve to the intake actually flows... i have found a few of them clogged..   don't tear the tape off the new pair.. its actually in the right spot..

it is an OBD2 jeep.. so you can plug in an OBD2 scan tool that will read the codes.. same as the key trick.. but better obd2 scan tools can display live data stream...  what the sensors are telling the ECM...  

dumpsterdom89 dumpsterdom89
New User | Posts: 12 | Joined: 04/12
Posted: 04/14/12
05:10 PM

Thanks man.  I have already gotten codes for bad 02 sensors. Likely upstream. I have had it in some water and some splashes, due to flooding in my area last fall, but splashes and deep water have been encountered as far back as 08.  I am at work for the next week and do not have the jeep (got the Harley baby).  I will take all of this advice into consideration when I bring it to my mechanic.  His hunch said that it's the O2 sensors giving the motor a bad blend. Are you familiar with this problem in vehicles??  I have never heard of such a weird issue. It sounds like it's on its last leg and then poof   it's fine.  

waynep71222 waynep71222
Guru | Posts: 825 | Joined: 03/12
Posted: 04/14/12
07:38 PM

do you know what codes???

do you own a digital volt meter..   they are cheep.. you can get nice ones for under 25 bucks..  try not to get an auto ranging version..  find one that has a Bunch of setting for each section..

set it to 20 volts DC...

start the engine .. turn on the headlights...

1. test from the Negative battery POST to the Positive battery POST...  14.1 to 14.8 volts is expected

2, test from the Negative battery POST to the Engine block/cylinder head,  0.04 volts DC is expected.

3. test from the Negative battery post to the body...      0.02 volts DC is expected..

4. test from the ENGINE BLOCK to the BODY..     0.02 volts is expected..

if you get 0.00 on the tests.. try again with the meter setting at 2 volts DC...   readings 0.00 are bad.. shows there is no current flowing between the parts and there should be with the engine running and the headlights on...


why did i want you to clean the grounds...

earlier this year.. a friend bought a 2000 voyager mini van.. it ran like crud..   a a bunch of codes..

when i ran the 4 part test above on it..  it failed... i forgot the numbers.. i started taking things apart to clean the cables...  found the ground cable at back of the head slightly dirty.. but the ground cable that is bolted to the top of the frame rail UNDER the battery tray really corroded..

when i cleaned the grounds.. cleared the codes.. test drove the van.. it drove perfect..

a friend with a chevy truck had stalling issues..   on test 4 i measured 8.5 volts..   from the engine to the body..  on the ground side.. i took the ground cables off the front bottom of the block cleaned them.. no more issues..  he drives it 80 miles a day in here in la.. and it gets him everywhere..

just last week a friend brought over a 91 camry.. with issues.. running rough.. stalling.. 14.1 on the first test. but fluttering around..    the second was .08 and 3/4 were 1.1volts..   i found a stripped out stud where a ground wire was attached.. and then the main ground cable from the battery to the top of the transmission was just snug..  not tight just snug..   when we finished.. the charging voltage was rock solid at 14.65 volts..   2 was at .03... 3/4 were at .02.. perfect.. and the car had lost its hard to start and idling issues..  all i did was clean the grounds and the idle air control .. but i had done that before i cleaned the grounds.. and it was still idling bad..

like i said..  the grounds are on both sides of your engine.. down on the sides of the block where the transmission bolts on..


run the test.. takes 2 minutes..

if you have cracks in the exhaust it will set codes..  

dumpsterdom89 dumpsterdom89
New User | Posts: 12 | Joined: 04/12
Posted: 04/15/12
01:09 PM

Thanks Again. I do I have voltmeter.  I will do all of these things before I take it in for work.  

dumpsterdom89 dumpsterdom89
New User | Posts: 12 | Joined: 04/12
Posted: 04/19/12
03:59 PM

My mechanic looked at it. He said that since it's coding bad sensors, he would start with that and the tbp as well.  I am going to try to try cleaing my battery posts as well as my engine grounds...I will ask if my mechanic checked for exhaust leaks.

Did I mention that this problem only happens when the motor is started cold and allowed to sit and idle, it sputters and hesitates. Once in gear at low rpm it sputters a lurches and the motor clunks. If I put it in neutral, it goes away (revs flawlessly through the rpms), but once I put it back into gear it comes back until I manage to accelerate up to ~45 mph and then the jeep runs flawlessly.  

waynep71222 waynep71222
Guru | Posts: 825 | Joined: 03/12
Posted: 04/19/12
05:41 PM

run a test...

post the results.. 1, 2, 3, 4.

clean the grounds....

run the voltage drop test again

why... to verify that you have fixed the problem..   before changing sensors..

you will also. probably want to clean the throttle body bore.. this is done engine off.. air inlet off.. give it a short blast of carb cleaner or brake cleaner.. cheeper is better on brake cleaner..  then wipe the bore out with a shop towel  while holding the throttle wide open.   wipe the throttle blades..

this is the idle speed control motor...     you might want to UNPLUG it..    then using Torx bit tools.. remove it from the throttle body.. clean the opening and passages..  DO NOT GET spray into the motor..   DO NOT remove it while it  is plugged in..   the computer extends the tapered part till it stops against the housing.. if you have it out. .it will extend all the way and drop out.. make you need to buy another.. its a stepper motor.. so its NOT easy to move it in and out with out some electronics..  

dumpsterdom89 dumpsterdom89
New User | Posts: 12 | Joined: 04/12
Posted: 04/19/12
06:04 PM

I will.  I'm gonna be home this weekend, so I'll get into it then.  


Thanks again  

dumpsterdom89 dumpsterdom89
New User | Posts: 12 | Joined: 04/12
Posted: 04/23/12
03:37 PM

P 0141, P 0161 are the codes on my digital display.  

waynep71222 waynep71222
Guru | Posts: 825 | Joined: 03/12
Posted: 04/23/12
04:44 PM

this is probably going to take a scan tool to properly diagnose...

P0141-1/2 O2 SENSOR HEATER FAILURE
When Monitored: With battery voltage greater than 9 volts, at a cold start, ECT less than
147°F, battery temperature sensor equal to or less than 27°F, and engine at idle for at least
12 seconds.
Set Condition: O2 sensor voltage greater than 3 volts for 60 to 240 seconds.

POSSIBLE CAUSES

O2 HEATER ELEMENT

O2 SENSOR HEATER GROUND CIRCUIT OPEN

O2 HEATER RELAY OUTPUT CIRCUIT OPEN



1 Turn the ignition on.
With the DRBIIIt, read DTC’s.
Is the Good Trip Counter for this DTC displayed and equal to zero?
All
No ® Go To 3
Yes ® Go To 2

2 Turn the ignition off.
NOTE: Wait a minimum of 8 minutes to allow the O2 Sensor to cool down
before continuing the test. Allow the O2 Sensor voltage to stabilize between
0.4 to 0.6 volts.
Turn the ignition on.
With the DRBIIIt, actuate the O2 Heater Test.
With the DRBIIIt, monitor O2 Sensor voltage for at least 2 minutes.
Does the voltage stay between 0.4 and 0.6 volt?
All
Yes ® Go To 3
No ® Go To 7

3 NOTE: Allow the O2 sensor to cool down to room temperature.
Turn the ignition off.
Disconnect the O2 Sensor harness connector.
Measure the resistance across the O2 Sensor Heater element component side.
Is the resistance between 4.0 and 7.0 ohms?
All
Yes ® Go To 4
No ® Replace the O2 Sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 5.

4 Turn the ignition off.
Disconnect the O2 Sensor harness connector.
Measure the resistance of the O2 Sensor Heater ground circuit in the O2 Sensor
harness connector.
Is the resistance below 5.0 ohms?
All
Yes ® Go To 5
No ® Repair the O2 Sensor Heater ground circuit for an open.
Perform POWERTRAIN VERIFICATION TEST VER - 5.

5 Turn the ignition off.
Disconnect the O2 Sensor harness connector.
With the DRBIIIt, actuate the O2 Heater Test.
Measure the voltage of the O2 Heater Relay Output circuit in the O2 Sensor harness
connector.
Is the voltage above 11.0 volts?
All
Yes ® Go To 6
No ® Repair the O2 Heater Relay Output circuit for an open.
Perform POWERTRAIN VERIFICATION TEST VER - 5.

6 If there are no possible causes remaining, view repair. All
Repair
Replace the Powertrain Control Module.
Perform POWERTRAIN VERIFICATION TEST VER - 5.


7 WARNING: KEEP CLEAR OF THE ENGINE’S MOVING PARTS.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
With the engine running at normal operating temperature, monitor the DRBIIIt
parameters related to the DTC while wiggling the wiring harness. Look for parameter
values to change and/or a DTC to set.
Review the DRBIIIt Freeze Frame information. If possible, try to duplicate the
conditions under which the DTC was set.
Refer to any Technical Service Bulletins (TSB) that may apply.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?
All
Yes ® Repair as necessary
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No ® Test Complete.


wayne says...   must look at Oxygen sensor voltage with a scan tool..... probably a bad ground on the sensor connector.. or a bad ground on the engine someplace..   remember.. i mentioned cleaning all the grounds...

it takes a scan tool to clear these codes..

if you don't have a scan tool.. think about a harbor freight 98614.. its the least expensive that actually displays live data and Graphs the sensor voltages.. so you can see the voltage swings of the oxygen sensor and other sensors.. this is a must have feature ..  they are 130 bucks..

more to come..  

waynep71222 waynep71222
Guru | Posts: 825 | Joined: 03/12
Posted: 04/23/12
04:50 PM

the 2 codes you have are for the same failure on a different oxygen sensor

Symptom List:
P0135-1/1 O2 SENSOR HEATER FAILURE
P0141-1/2 O2 SENSOR HEATER FAILURE
P0155-2/1 O2 SENSOR HEATER FAILURE
P0161-2/2 O2 SENSOR HEATER FAILURE

same exact info as above.. except a different location of the sensor..

the P0141 and the P0161 are both on the oxygen sensors AFTER the cats..    

see the 1/1 and the 1/2..

1/1 is bank one.. sensor one... thats before the cat on the first bank of cylinders..

1/2 is the first bank of cylinders but the second sensor.. after the cat..


before erasing the codes.. please.. look at and perhaps record the snap shot data stream and record it..  it will show what the system was doing at the exact time the code set..  

dumpsterdom89 dumpsterdom89
New User | Posts: 12 | Joined: 04/12
Posted: 04/23/12
05:09 PM

I have California emission pack, so the two at the top of header?  

dumpsterdom89 dumpsterdom89
New User | Posts: 12 | Joined: 04/12
Posted: 04/23/12
05:09 PM

I have California emission pack, so the two at the bottom of header?  

waynep71222 waynep71222
Guru | Posts: 825 | Joined: 03/12
Posted: 04/23/12
05:09 PM

the oxygen sensors seem to be grounded to the engine ground point..  still looking for that..  

dumpsterdom89 dumpsterdom89
New User | Posts: 12 | Joined: 04/12
Posted: 04/25/12
02:52 AM

I live just south of erie, pa.  Snow and salt every year.  I already have the new sensors. Just gotta get the time to do the work.  

When I do have time, I will just replace the sensors, clean the battery posts and engine ground connections.

Can anyone give me a quick rundown on how to replace the fan clutch? I have the new one. It doesn't look like it will come out w/o removing the radiator shroud...

I got some throttle body/air intake aerosol. Do I just pop the air filter compartment off the top of the intake and give er a spray or two?

Thanks Again.  

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