Mechanics

DODGE DURANGO ABS PROBLEM

2002 Dodge Durango

Engine Performance problem
2002 Dodge Durango V8 Two Wheel Drive Automatic 90000 miles

2002 Dodge Durango 4.7L V8.

Wednesday of last week I drove through about 6 to 12 inches of water on the freeway at about 55 MPH. Immediately after this unexpectedly large puddle, the engine started to run rough. There was quite a bit of vibration and it sounded much louder, almost like a modified exhaust (though the exhaust is stock). I pulled off at the next exit and took a quick look at the air intake -- no signs of water there. I let the engine idle for a few minutes and revved it a few times -- no change, still rough but running nonetheless. The engine continued to run rough through the remainder of the week and into the weekend, although I did not drive it anywhere except home after the incident and only started and revved it a bit once a day.

Over the weekend I opened the air filter box and took a closer look at the air intake. There was a layer of dust throughout the intake duct up until the air filter and the filter was dry, so obviously no water had been through the air intake.

I suspect that some water got into some of the electronics, although I haven't been able to determine where. Checked for trouble codes with a scanner -- there were none. Checked all of the fuses with a multimeter -- all were good. Checked the voltage across the terminals of the camshaft position sensor (CPS) connector -- good. I would have liked to check the voltage across the CPS with the engine running but could not connect the multimeter to the CPS while the connector was connected so instead I tried running the engine with the CPS disconnected to see if there was any difference. There was, the engine would not start, so I believe the CPS is ok. Checked for a misfiring cylinder due to a bad ignition coil or fuel injector, but the results so far have been inconclusive. Checked all cylinders with an IR thermometer (a cooler cylinder would indicate that it is not firing) -- most cylinders warmed at similar rates and reached about 170 degrees F except the 3rd from the front on the driver's side which warmed slower and reached about 150 (slightly cooler but hotter than I expected for a misfiring cylinder). With the engine running, disconnected the connector on the ignition coil over each cylinder one at a time -- each seemed to change the sound of the engine slightly, but it was hard to tell. I think the computer quickly sensed the disconnected coil and adjusted the timing to compensate. A trouble code was produced for each connector that was pulled stating that there was an error in the primary and secondary circuit of the ignition coil. Gave up on that test and moved on. Removed the ignition coil from the slightly cooler cylinder and used a calibrated tester to check for a spark -- it sparked. Checked each coil's primary resistance on all cylinders -- good. Did not bother checking the voltage across the fuel injectors after reading the service manual's section on fuel injectors and the PCM (computer); supposedly the computer would show a trouble code if the engine is running too rich/lean or misfiring.

I'm planning to pull the remaining ignition coils and test for sparks. The computer cannot detect a failure in an ignition coil's secondary circuit, so it's possible that one coil is not firing even though there are no trouble codes. If all coils are good I might even check the fuel injectors with a multimeter just to be sure that the computer isn't missing a malfunctioning fuel injector. Any other suggestions would be greatly appreciated.

Thanks!
Avatar
2002Durango
October 25, 2010.



Hi 2002Durango. Welcome to the forum. You did a lot of dandy tests already, but I might be able to add some information. The Engine Computer CAN detect a misfire since the 1996 models with OBD2 emissions systems, but not in the way you're thinking. It does it by detecting the crankshaft slowing down during the misfire event. That slowing of the crank is why we feel it. The computer won't know if fuel, spark, or compression caused the misfire, only that it occurred. The fact it hasn't set a misfire code for a specific cylinder suggests the possibility something else is going on. I can't speak to this specific problem exactly, but when some problems are detected, it prevents other self-tests from taking place. As an example, the computer knows you're coasting when it sees high manifold vacuum from the MAP sensor. With non-computer-controlled transmissions, coasting is when speed sensors are tested because the computer knows the car is moving. That sensor will not be tested when a MAP sensor code is in memory and the problem is currently acting up. I believe though misfire codes take priority over other problems and should be detected.

Next, when you disconnect the injectors while looking for a misfiring cylinder, it's not the timing that changes. It is the number of " steps" for the automatic idle speed motor that changes. That is a stepper motor. Rather than a motor with brushes and a spinning armature, it is four coils of wire that are pulsed with varying voltages and polarities by the computer to turn the armature to one of 256 positions (steps) within a total of about ten revolutions. As it rotates, a threaded rod retracts a pintle valve to expose more or less of an air passage around the throttle blade. As the number of steps increase, the number of milliseconds the injectors are held open increases too. The extra air and fuel increases engine speed.

If you can lay your hands on a scanner, you can read the number of steps the computer has commanded the AIS motor to. On a normally running engine, step number 32 is typical when the engine is warmed up. When you disconnect one coil or injector, the engine will slow down momentarily, then the computer will respond by increasing the number of AIS motor steps. Expect to see about step number 50. Since you can't go by rpm drop like we did years ago with carbureted engines, what you're looking for is a cylinder that doesn't cause a change in the number of steps when it is disabled. I have the Chrysler DRB2 and DRB3, but all aftermarket scanners will read the AIS steps as part of the live sensor data. To give you an idea of how much control the computer has, a Chrysler trainer showed us a demonstration where he disconnected six injectors while the engine was running, and it maintained the proper idle speed. Obviously it was running very poorly on just two cylinders, but the point was it was still running.

The scanner will also show the oxygen sensors switching rapidly between rich, lean, and centered. If one of them is stuck on lean, based on the recent history, look for an exhaust leak ahead of the catalytic converter. Between the puffs of exhaust, the momentum will draw in outside air that will be detected by the oxygen sensor as a lean condition. That will result in the computer increasing fuel metering to that bank of cylinders. Since the O2 sensor doesn't detect fuel, it will continue to see the extra oxygen while the computer keeps adding fuel. You could have three cylinders that are over-fueled and the computer thinks they're running lean. If the exhaust doesn't sound right, look for a spring-loaded pipe connection at the exhaust manifold to see if there is a donut gasket that is out of position.

I suspect your biggest clue is the sound of the exhaust. Even if there is another problem, fix the exhaust first so you know it is not adding to the computer's confusion. I should mention too to be sure the odd exhaust sound is indeed an exhaust problem and not just the sound of misfiring cylinders.

Caradiodoc

Caradiodoc
Oct 25, 2010.
Caradiodoc, thanks for your reply. A lot of great info there!

I finally got a chance to take another look today. I hooked up my scanner (Actron CP9180) and looked for the stepper motor position. Unfortunately, it looks like this scanner does not show it. The scanner manual shows that the scanner can display IAC (Idle Air Control) or ISC (Idle Speed Control) but it is not displaying either of these when connected to the car's PCM with the engine running.

I didn't notice any problems with the oxygen sensor readings. This car has a CA emissions package, so there are 4 O2 sensors and 3 catalytic converters. There are 2 " mini catalytic converters, " one on each exhaust pipe coming off of the exhaust manifold on either side of the engine. The two exhaust pipes then meet and feed into the " main catalytic converter.&Quot; Each mini cat has an O2 sensor before and after it. The O2 sensors can output 0-1 volts. The two sensors before the mini cats fluctuate between near 0 and near 1. The two sensors after the mini cats read around 0.8 volts pretty consistently. I'll copy the scanner data below. Please let me know if you see any problems with any of the data.

Thanks again!

Scanner code definitions (found using a combination of the scanner manual and car's shop manual): MIL STATUS
Malfunction Indicator Lamp On/Off.
ABSLT TPS %
Absolute Throttle Position percentage.
ENG SPEED RPM
Engine Speed in RPMs.
CALC LOAD %
Calculated Engine Load percentage.
MAP KPA
Manifold Absolute Pressure in kilopascals. InHg = 0.295300 × kPa.
COOLANT F
Coolant temperature in degrees fahrenheit.
IAT F
Intake Air Temperature in degrees fahrenheit.
IGN ADVANCE DE
Ignition advance. DE?
ST FTRM1 %
Short Term Fuel Trim percentage. Location?
LT FTRM1 %
Long Term Fuel Trim percentage. Location?
ST FTRM2 %
Short Term Fuel Trim percentage. Location?
LT FTRM2 %
Long Term Fuel Trim percentage. Location?
VEH SPEED MPH
Vehicle Speed in MPH.
FUEL SYS 1
Fuel System loop status. Closed: PCM monitors O2 sensors and adjusts fuel/air accordingly. Open: PCM not monitoring O2 sensors.
FUEL SYS 2
Fuel System loop status. Closed: PCM monitors O2 sensors and adjusts fuel/air accordingly. Open: PCM not monitoring O2 sensors.
O2S11 V
O2 Sensor, left exhaust downpipe before mini cat converter, output in volts. Voltage is inversely proportional to the amount of oxygen present. Range is 0 - 1.
ST FTRM11 %
Short Term Fuel Trim percentage. Location?
O2S12
O2 Sensor, left exhaust downpipe between mini cat converter and main cat converter, output in volts. Voltage is inversely proportional to the amount of oxygen present. Range is 0 - 1.
O2S21 V
O2 Sensor, right exhaust downpipe before mini cat converter, output in volts. Voltage is inversely proportional to the amount of oxygen present. Range is 0 - 1.
ST FTRM21 %
Short Term Fuel Trim percentage. Location?
O2S22
O2 Sensor, right exhaust downpipe between mini cat converter and main cat converter, output in volts. Voltage is inversely proportional to the amount of oxygen present. Range is 0 - 1.
MIL DIST mi
Distance since MIL illuminated.
OBD2 STAT
On Board Diagnostics 2 System Type.

Scanner data (idling, warm): Recorded Data

MIL STATUS OFF
MIL STATUS OFF
ABSLT TPS % 11.3
ABSLT TPS % 11.7
ENG SPEED RPM 604
ENG SPEED RPM 613
CALC LOAD % 5.0
MAP KPA 35
COOLANT F 204
IAT F 109
IGN ADVANCE DE 11.5
ST FTRM1 % -3.4
LT FTRM1 % 3.1
ST FTRM2 % -4.9
LT FTRM2 % 6.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 V 0.820
ST FTRM11 % -4.9
O2S12 V 0.820
O2S21 V 0.800
ST FTRM21 % -4.9
O2S22 V 0.800
MIL DIST mi 0
OBD2 STAT CA

Frame -5 Time -5.0

MIL STATUS($10) OFF
MIL STATUS($18) OFF
ABSLT TPS($10) 11.3
ABSLT TPS($18) 11.7
ENG SPEED($10) 607
ENG SPEED($18) 604
CALC LOAD($10) 5.0
MAP($10) 35
COOLANT($10) 204
IAT($10) 107
IGN ADVANCE($1 12.0
ST FTRM1($10) -4.9
LT FTRM1($10) 3.1
ST FTRM2($10) 0.0
LT FTRM2($10) 6.2
VEH SPEED($10) 0
FUEL SYS 1($10) CLSD
FUEL SYS 2($10) CLSD
O2S11($10) 0.800
ST FTRM11($10) -4.6
O2S12($10) 0.800
O2S21($10) 0.685
ST FTRM21($10) -3.4
O2S22($10) 0.800
MIL DIST($10) 0
OBD2 STAT($10) CA

Frame -4 Time -4.0

MIL STATUS OFF
MIL STATUS OFF
ABSLT TPS % 11.3
ABSLT TPS % 11.3
ENG SPEED RPM 608
ENG SPEED RPM 591
CALC LOAD % 5.0
MAP KPA 35
COOLANT F 204
IAT F 107
IGN ADVANCE DE 12.0
ST FTRM1 % 0.0
LT FTRM1 % 3.1
ST FTRM2 % -3.4
LT FTRM2 % 6.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 V 0.310
ST FTRM11 % -1.0
O2S12 V 0.800
O2S21 V 0.780
ST FTRM21 % -2.2
O2S22 V 0.820
MIL DIST mi 0
OBD2 STAT CA

Frame -3 Time -3.0

MIL STATUS($10) OFF
MIL STATUS($18) OFF
ABSLT TPS($10) 11.3
ABSLT TPS($18) 11.7
ENG SPEED($10) 613
ENG SPEED($18) 610
CALC LOAD($10) 5.0
MAP($10) 35
COOLANT($10) 204
IAT($10) 109
IGN ADVANCE($1 12.0
ST FTRM1($10) -4.6
LT FTRM1($10) 3.1
ST FTRM2($10) 0.8
LT FTRM2($10) 6.2
VEH SPEED($10) 0
FUEL SYS 1($10) CLSD
FUEL SYS 2($10) CLSD
O2S11($10) 0.840
ST FTRM11($10) -4.6
O2S12($10) 0.800
O2S21($10) 0.645
ST FTRM21($10) -3.4
O2S22($10) 0.780
MIL DIST($10) 0
OBD2 STAT($10) CA

Frame -2 Time -2.0

MIL STATUS OFF
MIL STATUS OFF
ABSLT TPS % 11.3
ABSLT TPS % 11.7
ENG SPEED RPM 595
ENG SPEED RPM 601
CALC LOAD % 4.7
MAP KPA 35
COOLANT F 204
IAT F 111
IGN ADVANCE DE 11.5
ST FTRM1 % 0.0
LT FTRM1 % 3.1
ST FTRM2 % -2.2
LT FTRM2 % 6.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 V 0.075
ST FTRM11 % 0.7
O2S12 V 0.780
O2S21 V 0.075
ST FTRM21 % 0.7
O2S22 V 0.800
MIL DIST mi 0
OBD2 STAT CA

Frame -1 Time -1.0

MIL STATUS($10) OFF
MIL STATUS($18) OFF
ABSLT TPS($10) 11.3
ABSLT TPS($18) 11.7
ENG SPEED($10) 606
ENG SPEED($18) 606
CALC LOAD($10) 5.0
MAP($10) 35
COOLANT($10) 204
IAT($10) 111
IGN ADVANCE($1 10.0
ST FTRM1($10) -1.0
LT FTRM1($10) 3.1
ST FTRM2($10) -2.2
LT FTRM2($10) 6.2
VEH SPEED($10) 0
FUEL SYS 1($10) CLSD
FUEL SYS 2($10) CLSD
O2S11($10) 0.135
ST FTRM11($10) 0.0
O2S12($10) 0.780
O2S21($10) 0.800
ST FTRM21($10) -2.2
O2S22($10) 0.780
MIL DIST($10) 0
OBD2 STAT($10) CA

Frame 0 Time 0.0

MIL STATUS OFF
MIL STATUS OFF
ABSLT TPS % 11.3
ABSLT TPS % 11.7
ENG SPEED RPM 602
ENG SPEED RPM 606
CALC LOAD % 5.0
MAP KPA 35
COOLANT F 204
IAT F 111
IGN ADVANCE DE 11.5
ST FTRM1 % 0.0
LT FTRM1 % 3.1
ST FTRM2 % 0.7
LT FTRM2 % 6.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 V 0.310
ST FTRM11 % 0.0
O2S12 V 0.780
O2S21 V 0.075
ST FTRM21 % 0.7
O2S22 V 0.780
MIL DIST mi 0
OBD2 STAT CA

Frame 1 Time 1.1

MIL STATUS($10) OFF
MIL STATUS($18) OFF
ABSLT TPS($10) 11.3
ABSLT TPS($18) 11.7
ENG SPEED($10) 605
ENG SPEED($18) 605
CALC LOAD($10) 5.0
MAP($10) 35
COOLANT($10) 204
IAT($10) 111
IGN ADVANCE($1 13.0
ST FTRM1($10) -1.0
LT FTRM1($10) 3.1
ST FTRM2($10) 0.8
LT FTRM2($10) 6.2
VEH SPEED($10) 0
FUEL SYS 1($10) CLSD
FUEL SYS 2($10) CLSD
O2S11($10) 0.840
ST FTRM11($10) 0.8
O2S12($10) 0.780
O2S21($10) 0.820
ST FTRM21($10) 0.8
O2S22($10) 0.800
MIL DIST($10) 0
OBD2 STAT($10) CA

Frame 2 Time 2.2

MIL STATUS OFF
MIL STATUS OFF
ABSLT TPS % 11.3
ABSLT TPS % 11.7
ENG SPEED RPM 595
ENG SPEED RPM 587
CALC LOAD % 5.0
MAP KPA 35
COOLANT F 204
IAT F 111
IGN ADVANCE DE 13.0
ST FTRM1 % 1.5
LT FTRM1 % 3.1
ST FTRM2 % 0.8
LT FTRM2 % 6.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 V 0.195
ST FTRM11 % 1.5
O2S12 V 0.780
O2S21 V 0.800
ST FTRM21 % 0.0
O2S22 V 0.780
MIL DIST mi 0
OBD2 STAT CA

Frame 3 Time 3.2

MIL STATUS($10) OFF
MIL STATUS($18) OFF
ABSLT TPS($10) 11.3
ABSLT TPS($18) 11.3
ENG SPEED($10) 599
ENG SPEED($18) 604
CALC LOAD($10) 5.0
MAP($10) 34
COOLANT($10) 204
IAT($10) 111
IGN ADVANCE($1 12.0
ST FTRM1($10) -1.0
LT FTRM1($10) 3.1
ST FTRM2($10) 0.8
LT FTRM2($10) 6.2
VEH SPEED($10) 0
FUEL SYS 1($10) CLSD
FUEL SYS 2($10) CLSD
O2S11($10) 0.780
ST FTRM11($10) 0.8
O2S12($10) 0.780
O2S21($10) 0.800
ST FTRM21($10) 0.8
O2S22($10) 0.780
MIL DIST($10) 0
OBD2 STAT($10) CA

Frame 4 Time 4.2

MIL STATUS OFF
MIL STATUS OFF
ABSLT TPS % 11.3
ABSLT TPS % 11.7
ENG SPEED RPM 594
ENG SPEED RPM 596
CALC LOAD % 5.0
MAP KPA 35
COOLANT F 204
IAT F 111
IGN ADVANCE DE 8.5
ST FTRM1 % 2.3
LT FTRM1 % 3.1
ST FTRM2 % 3.1
LT FTRM2 % 6.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 V 0.195
ST FTRM11 % 5.4
O2S12 V 0.780
O2S21 V 0.450
ST FTRM21 % 5.4
O2S22 V 0.760
MIL DIST mi 0
OBD2 STAT CA

Frame 5 Time 5.2

MIL STATUS($10) OFF
MIL STATUS($18) OFF
ABSLT TPS($10) 11.3
ABSLT TPS($18) 11.7
ENG SPEED($10) 611
ENG SPEED($18) 609
CALC LOAD($10) 5.0
MAP($10) 35
COOLANT($10) 204
IAT($10) 111
IGN ADVANCE($1 9.0
ST FTRM1($10) 7.8
LT FTRM1($10) 3.1
ST FTRM2($10) 3.9
LT FTRM2($10) 6.2
VEH SPEED($10) 0
FUEL SYS 1($10) CLSD
FUEL SYS 2($10) CLSD
O2S11($10) 0.780
ST FTRM11($10) 5.4
O2S12($10) 0.760
O2S21($10) 0.800
ST FTRM21($10) 3.9
O2S22($10) 0.760
MIL DIST($10) 0
OBD2 STAT($10) CA

Frame 6 Time 6.2

MIL STATUS OFF
MIL STATUS OFF
ABSLT TPS % 11.3
ABSLT TPS % 11.7
ENG SPEED RPM 607
ENG SPEED RPM 601
CALC LOAD % 5.0
MAP KPA 35
COOLANT F 204
IAT F 113
IGN ADVANCE DE 11.5
ST FTRM1 % 3.1
LT FTRM1 % 3.1
ST FTRM2 % 3.1
LT FTRM2 % 6.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 V 0.450
ST FTRM11 % 3.1
O2S12 V 0.780
O2S21 V 0.760
ST FTRM21 % 3.1
O2S22 V 0.760
MIL DIST mi 0
OBD2 STAT CA

Frame 7 Time 7.2

MIL STATUS($10) OFF
MIL STATUS($18) OFF
ABSLT TPS($10) 11.3
ABSLT TPS($18) 11.7
ENG SPEED($10) 593
ENG SPEED($18) 609
CALC LOAD($10) 5.0
MAP($10) 35
COOLANT($10) 204
IAT($10) 113
IGN ADVANCE($1 10.5
ST FTRM1($10) 6.2
LT FTRM1($10) 3.1
ST FTRM2($10) 4.6
LT FTRM2($10) 6.2
VEH SPEED($10) 0
FUEL SYS 1($10) CLSD
FUEL SYS 2($10) CLSD
O2S11($10) 0.860
ST FTRM11($10) 1.5
O2S12($10) 0.780
O2S21($10) 0.490
ST FTRM21($10) 3.1
O2S22($10) 0.780
MIL DIST($10) 0
OBD2 STAT($10) CA

Frame 8 Time 8.2

MIL STATUS OFF
MIL STATUS OFF
ABSLT TPS % 11.3
ABSLT TPS % 11.7
ENG SPEED RPM 588
ENG SPEED RPM 599
CALC LOAD % 5.0
MAP KPA 35
COOLANT F 204
IAT F 113
IGN ADVANCE DE 12.0
ST FTRM1 % 0.7
LT FTRM1 % 3.1
ST FTRM2 % 2.3
LT FTRM2 % 6.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 V 0.840
ST FTRM11 % 0.7
O2S12 V 0.780
O2S21 V 0.820
ST FTRM21 % 0.7
O2S22 V 0.780
MIL DIST mi 0
OBD2 STAT CA

Frame 9 Time 9.2

MIL STATUS($10) OFF
MIL STATUS($18) OFF
ABSLT TPS($10) 11.3
ABSLT TPS($18) 11.3
ENG SPEED($10) 602
ENG SPEED($18) 611
CALC LOAD($10) 5.0
MAP($10) 35
COOLANT($10) 204
IAT($10) 113
IGN ADVANCE($1 9.0
ST FTRM1($10) 0.7
LT FTRM1($10) 3.1
ST FTRM2($10) 1.5
LT FTRM2($10) 6.2
VEH SPEED($10) 0
FUEL SYS 1($10) CLSD
FUEL SYS 2($10) CLSD
O2S11($10) 0.155
ST FTRM11($10) 0.7
O2S12($10) 0.780
O2S21($10) 0.310
ST FTRM21($10) 2.3
O2S22($10) 0.760
MIL DIST($10) 0
OBD2 STAT($10) CA

Frame 10 Time 10.2

MIL STATUS OFF
MIL STATUS OFF
ABSLT TPS % 11.3
ABSLT TPS % 11.7
ENG SPEED RPM 601
ENG SPEED RPM 593
CALC LOAD % 5.0
MAP KPA 35
COOLANT F 204
IAT F 114
IGN ADVANCE DE 12.0
ST FTRM1 % -1.0
LT FTRM1 % 3.1
ST FTRM2 % 0.0
LT FTRM2 % 6.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 V 0.760
ST FTRM11 % 0.8
O2S12 V 0.780
O2S21 V 0.175
ST FTRM21 % 2.3
O2S22 V 0.780
MIL DIST mi 0
OBD2 STAT CA

Frame 11 Time 11.2

MIL STATUS($10) OFF
MIL STATUS($18) OFF
ABSLT TPS($10) 11.3
ABSLT TPS($18) 11.3
ENG SPEED($10) 597
ENG SPEED($18) 600
CALC LOAD($10) 5.0
MAP($10) 34
COOLANT($10) 204
IAT($10) 114
IGN ADVANCE($1 11.5
ST FTRM1($10) 0.0
LT FTRM1($10) 3.1
ST FTRM2($10) 1.5
LT FTRM2($10) 6.2
VEH SPEED($10) 0
FUEL SYS 1($10) CLSD
FUEL SYS 2($10) CLSD
O2S11($10) 0.745
ST FTRM11($10) 0.8
O2S12($10) 0.780
O2S21($10) 0.175
ST FTRM21($10) 0.7
O2S22($10) 0.760
MIL DIST($10) 0
OBD2 STAT($10) CA

Frame 12 Time 12.2

MIL STATUS OFF
MIL STATUS OFF
ABSLT TPS % 11.3
ABSLT TPS % 11.3
ENG SPEED RPM 611
ENG SPEED RPM 600
CALC LOAD % 5.0
MAP KPA 34
COOLANT F 204
IAT F 114
IGN ADVANCE DE 8.5
ST FTRM1 % 0.7
LT FTRM1 % 3.1
ST FTRM2 % -2.2
LT FTRM2 % 6.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 V 0.155
ST FTRM11 % 0.7
O2S12 V 0.780
O2S21 V 0.745
ST FTRM21 % -1.0
O2S22 V 0.780
MIL DIST mi 0
OBD2 STAT CA

Frame 13 Time 13.2

MIL STATUS($10) OFF
MIL STATUS($18) OFF
ABSLT TPS($10) 11.3
ABSLT TPS($18) 11.3
ENG SPEED($10) 613
ENG SPEED($18) 615
CALC LOAD($10) 5.0
MAP($10) 34
COOLANT($10) 204
IAT($10) 114
IGN ADVANCE($1 11.5
ST FTRM1($10) -1.0
LT FTRM1($10) 3.1
ST FTRM2($10) -2.2
LT FTRM2($10) 6.2
VEH SPEED($10) 0
FUEL SYS 1($10) CLSD
FUEL SYS 2($10) CLSD
O2S11($10) 0.780
ST FTRM11($10) -2.2
O2S12($10) 0.760
O2S21($10) 0.745
ST FTRM21($10) -1.0
O2S22($10) 0.780
MIL DIST($10) 0
OBD2 STAT($10) CA

Frame 14 Time 14.2

MIL STATUS OFF
MIL STATUS OFF
ABSLT TPS % 11.3
ABSLT TPS % 11.7
ENG SPEED RPM 585
ENG SPEED RPM 600
CALC LOAD % 5.0
MAP KPA 35
COOLANT F 204
IAT F 114
IGN ADVANCE DE 10.5
ST FTRM1 % -1.0
LT FTRM1 % 3.1
ST FTRM2 % 0.0
LT FTRM2 % 6.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 V 0.115
ST FTRM11 % 1.5
O2S12 V 0.780
O2S21 V 0.800
ST FTRM21 % -2.2
O2S22 V 0.760
MIL DIST mi 0
OBD2 STAT CA

Frame 15 Time 15.2

MIL STATUS($10) OFF
MIL STATUS($18) OFF
ABSLT TPS($10) 11.3
ABSLT TPS($18) 11.7
ENG SPEED($10) 603
ENG SPEED($18) 591
CALC LOAD($10) 5.0
MAP($10) 34
COOLANT($10) 204
IAT($10) 114
IGN ADVANCE($1 13.5
ST FTRM1($10) 0.7
LT FTRM1($10) 3.1
ST FTRM2($10) 0.8
LT FTRM2($10) 6.2
VEH SPEED($10) 0
FUEL SYS 1($10) CLSD
FUEL SYS 2($10) CLSD
O2S11($10) 0.310
ST FTRM11($10) -1.0
O2S12($10) 0.780
O2S21($10) 0.115
ST FTRM21($10) 1.5
O2S22($10) 0.780
MIL DIST($10) 0
OBD2 STAT($10) CA

Frame 16 Time 16.2

MIL STATUS OFF
MIL STATUS OFF
ABSLT TPS % 11.3
ABSLT TPS % 11.7
ENG SPEED RPM 597
ENG SPEED RPM 590
CALC LOAD % 5.0
MAP KPA 34
COOLANT F 204
IAT F 114
IGN ADVANCE DE 12.0
ST FTRM1 % -1.0
LT FTRM1 % 3.1
ST FTRM2 % -1.0
LT FTRM2 % 6.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 V 0.665
ST FTRM11 % -1.0
O2S12 V 0.760
O2S21 V 0.075
ST FTRM21 % 0.8
O2S22 V 0.760
MIL DIST mi 0
OBD2 STAT CA

Frame 17 Time 17.2

MIL STATUS($10) OFF
MIL STATUS($18) OFF
ABSLT TPS($10) 11.3
ABSLT TPS($18) 11.3
ENG SPEED($10) 610
ENG SPEED($18) 601
CALC LOAD($10) 5.0
MAP($10) 34
COOLANT($10) 204
IAT($10) 113
IGN ADVANCE($1 12.0
ST FTRM1($10) 1.5
LT FTRM1($10) 3.1
ST FTRM2($10) 0.0
LT FTRM2($10) 6.2
VEH SPEED($10) 0
FUEL SYS 1($10) CLSD
FUEL SYS 2($10) CLSD
O2S11($10) 0.175
ST FTRM11($10) 0.7
O2S12($10) 0.760
O2S21($10) 0.095
ST FTRM21($10) 1.5
O2S22($10) 0.760
MIL DIST($10) 0
OBD2 STAT($10) CA

Frame 18 Time 18.3

MIL STATUS OFF
MIL STATUS OFF
ABSLT TPS % 11.3
ABSLT TPS % 11.3
ENG SPEED RPM 597
ENG SPEED RPM 602
CALC LOAD % 5.0
MAP KPA 34
COOLANT F 204
IAT F 113
IGN ADVANCE DE 9.5
ST FTRM1 % -1.0
LT FTRM1 % 3.1
ST FTRM2 % -1.0
LT FTRM2 % 6.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 V 0.390
ST FTRM11 % 0.8
O2S12 V 0.780
O2S21 V 0.075
ST FTRM21 % 2.3
O2S22 V 0.760
MIL DIST mi 0
OBD2 STAT CA

Frame 19 Time 19.3

MIL STATUS($10) OFF
MIL STATUS($18) OFF
ABSLT TPS($10) 11.3
ABSLT TPS($18) 11.3
ENG SPEED($10) 602
ENG SPEED($18) 593
CALC LOAD($10) 5.0
MAP($10) 34
COOLANT($10) 204
IAT($10) 113
IGN ADVANCE($1 14.0
ST FTRM1($10) -1.0
LT FTRM1($10) 3.1
ST FTRM2($10) -1.0
LT FTRM2($10) 6.2
VEH SPEED($10) 0
FUEL SYS 1($10) CLSD
FUEL SYS 2($10) CLSD
O2S11($10) 0.490
ST FTRM11($10) -1.0
O2S12($10) 0.780
O2S21($10) 0.155
ST FTRM21($10) 0.8
O2S22($10) 0.760
MIL DIST($10) 0
OBD2 STAT($10) CA

Frame 20 Time 20.3

MIL STATUS OFF
MIL STATUS OFF
ABSLT TPS % 11.3
ABSLT TPS % 11.3
ENG SPEED RPM 593
ENG SPEED RPM 609
CALC LOAD % 5.0
MAP KPA 34
COOLANT F 204
IAT F 114
IGN ADVANCE DE 11.0
ST FTRM1 % 0.7
LT FTRM1 % 3.1
ST FTRM2 % 0.0
LT FTRM2 % 6.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 V 0.075
ST FTRM11 % 1.5
O2S12 V 0.760
O2S21 V 0.725
ST FTRM21 % -1.0
O2S22 V 0.760
MIL DIST mi 0
OBD2 STAT CA

Frame 21 Time 21.3

MIL STATUS($10) OFF
MIL STATUS($18) OFF
ABSLT TPS($10) 11.3
ABSLT TPS($18) 11.3
ENG SPEED($10) 590
ENG SPEED($18) 604
CALC LOAD($10) 5.0
MAP($10) 34
COOLANT($10) 204
IAT($10) 116
IGN ADVANCE($1 10.0
ST FTRM1($10) 0.7
LT FTRM1($10) 3.1
ST FTRM2($10) 1.5
LT FTRM2($10) 6.2
VEH SPEED($10) 0
FUEL SYS 1($10) CLSD
FUEL SYS 2($10) CLSD
O2S11($10) 0.800
ST FTRM11($10) 0.0
O2S12($10) 0.780
O2S21($10) 0.330
ST FTRM21($10) 0.0
O2S22($10) 0.780
MIL DIST($10) 0
OBD2 STAT($10) CA

Frame 22 Time 22.3

MIL STATUS OFF
MIL STATUS OFF
ABSLT TPS % 11.3
ABSLT TPS % 11.7
ENG SPEED RPM 596
ENG SPEED RPM 606
CALC LOAD % 4.7
MAP KPA 34
COOLANT F 204
IAT F 116
IGN ADVANCE DE 11.0
ST FTRM1 % -2.2
LT FTRM1 % 3.1
ST FTRM2 % 0.0
LT FTRM2 % 6.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 V 0.800
ST FTRM11 % -1.0
O2S12 V 0.780
O2S21 V 0.760
ST FTRM21 % -1.0
O2S22 V 0.760
MIL DIST mi 0
OBD2 STAT CA

Frame 23 Time 23.3

MIL STATUS($10) OFF
MIL STATUS($18) OFF
ABSLT TPS($10) 11.3
ABSLT TPS($18) 11.3
ENG SPEED($10) 609
ENG SPEED($18) 593
CALC LOAD($10) 5.0
MAP($10) 34
COOLANT($10) 204
IAT($10) 113
IGN ADVANCE($1 14.0
ST FTRM1($10) 0.0
LT FTRM1($10) 3.1
ST FTRM2($10) 2.3
LT FTRM2($10) 6.2
VEH SPEED($10) 0
FUEL SYS 1($10) CLSD
FUEL SYS 2($10) CLSD
O2S11($10) 0.665
ST FTRM11($10) -1.0
O2S12($10) 0.780
O2S21($10) 0.705
ST FTRM21($10) 0.8
O2S22($10) 0.760
MIL DIST($10) 0
OBD2 STAT($10) CA

Frame 24 Time 24.3

MIL STATUS OFF
MIL STATUS OFF
ABSLT TPS % 11.3
ABSLT TPS % 11.3
ENG SPEED RPM 606
ENG SPEED RPM 606
CALC LOAD % 5.0
MAP KPA 34
COOLANT F 204
IAT F 111
IGN ADVANCE DE 7.5
ST FTRM1 % 1.5
LT FTRM1 % 3.1
ST FTRM2 % 3.1
LT FTRM2 % 6.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 V 0.135
ST FTRM11 % 2.3
O2S12 V 0.780
O2S21 V 0.745
ST FTRM21 % 0.8
O2S22 V 0.760
MIL DIST mi 0
OBD2 STAT CA

Frame 25 Time 25.3

MIL STATUS($10) OFF
MIL STATUS($18) OFF
ABSLT TPS($10) 11.3
ABSLT TPS($18) 11.7
ENG SPEED($10) 608
ENG SPEED($18) 614
CALC LOAD($10) 5.0
MAP($10) 34
COOLANT($10) 204
IAT($10) 113
IGN ADVANCE($1 10.5
ST FTRM1($10) 0.0
LT FTRM1($10) 3.1
ST FTRM2($10) 1.5
LT FTRM2($10) 6.2
VEH SPEED($10) 0
FUEL SYS 1($10) CLSD
FUEL SYS 2($10) CLSD
O2S11($10) 0.840
ST FTRM11($10) 0.8
O2S12($10) 0.760
O2S21($10) 0.820
ST FTRM21($10) 0.8
O2S22($10) 0.760
MIL DIST($10) 0
OBD2 STAT($10) CA

Frame 26 Time 26.3

MIL STATUS OFF
MIL STATUS OFF
ABSLT TPS % 11.3
ABSLT TPS % 11.3
ENG SPEED RPM 606
ENG SPEED RPM 607
CALC LOAD % 5.0
MAP KPA 34
COOLANT F 204
IAT F 113
IGN ADVANCE DE 8.5
ST FTRM1 % 0.0
LT FTRM1 % 3.1
ST FTRM2 % 0.8
LT FTRM2 % 6.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 V 0.820
ST FTRM11 % -1.0
O2S12 V 0.780
O2S21 V 0.820
ST FTRM21 % 0.8
O2S22 V 0.780
MIL DIST mi 0
OBD2 STAT CA

Frame 27 Time 27.3

MIL STATUS($10) OFF
MIL STATUS($18) OFF
ABSLT TPS($10) 11.3
ABSLT TPS($18) 11.3
ENG SPEED($10) 604
ENG SPEED($18) 596
CALC LOAD($10) 5.0
MAP($10) 34
COOLANT($10) 204
IAT($10) 111
IGN ADVANCE($1 9.5
ST FTRM1($10) -2.2
LT FTRM1($10) 3.1
ST FTRM2($10) -2.2
LT FTRM2($10) 6.2
VEH SPEED($10) 0
FUEL SYS 1($10) CLSD
FUEL SYS 2($10) CLSD
O2S11($10) 0.115
ST FTRM11($10) 0.7
O2S12($10) 0.780
O2S21($10) 0.705
ST FTRM21($10) -1.0
O2S22($10) 0.760
MIL DIST($10) 0
OBD2 STAT($10) CA

Frame 28 Time 28.3

MIL STATUS OFF
MIL STATUS OFF
ABSLT TPS % 11.3
ABSLT TPS % 11.3
ENG SPEED RPM 603
ENG SPEED RPM 609
CALC LOAD % 5.0
MAP KPA 34
COOLANT F 204
IAT F 111
IGN ADVANCE DE 10.0
ST FTRM1 % 0.7
LT FTRM1 % 3.1
ST FTRM2 % 0.0
LT FTRM2 % 6.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 CLSD
O2S11 V 0.745
ST FTRM11 % -3.4
O2S12 V 0.780
O2S21 V 0.685
ST FTRM21 % 0.0
O2S22 V 0.760
MIL DIST mi 0
OBD2 STAT CA

Frame 29 Time 29.3

Tiny
2002Durango
Oct 31, 2010.
The oxygen sensor readings seem to be fine. You'll notice the two in front of the catalytic converters, (O2S11 and 21), switch quite a bit from frame to frame and the downstream sensors, (O2S12 and 22) are hardly switching at all. That is normal.

While a 14.7 / 1 mixture is perfect for best combustion, if that were to be off a little, the O2 sensors can only detect a lean condition, and by how much. It can only detect a rich condition by the absence of extra unburned oxygen, but it won't know by how much. That's one reason the system is constantly switching between rich and lean. During the rich transitions which occur a few times per second, the Engine Computer knows how much extra fuel it is requesting based on the length of injector on-time and it sees how long it takes to get back to a lean condition when it reduces the amount of fuel.

Second, during the rich cycles, unburned hydrocarbons, (a fancy name for gasoline), are stored in the catalyst material. Later, when the unburned oxygen from the lean cycle comes down, it is mixed with the fuel and burned. From that point on, if things are working correctly, the exhaust leaving the converter will switch very slowly from a little rich to a little lean. Besides reading the actual values from the O2 sensors, the computer is watching the frequency at which they switch between rich and lean. The front sensors will switch rapidly, and they are the ones used for fuel delivery fine tuning. The rear sensors switch slowly when the catalytic converters are doing their job. When they are not working properly, often after being severely overheated, they do not change the composition of the exhaust gases flowing through them so the downstream sensors' switching rate will start to approach that of the upstream sensors. That's how the computer can detect converter efficiency and set related fault codes.

The only two things I noticed were a real high intake air temperature (IAT) and a somewhat high long term fuel trim on one bank. The IAT is probably over 100 degrees because the incoming air is the hot air around the engine, not the cool air on the highway. Regardless, that temperature is one of the readings that just sets the starting point for the fuel calculations. After that they are adjusted based on O2 sensor readings.

If you know how fuel trims work, I apologize for repeating it here, but it might help someone else searching for the cause of their problem. The starting values are programmed into the computer at the factory. They're called " lookup tables". That is an almost infinite set of values based on the huge variety and combination of sensor readings. Given any one value for coolant temperature, manifold vacuum / barometric pressure, intake air or battery temperature, oxygen sensor value, throttle position, speed of change, and direction of change, and engine speed, the computer goes to the lookup tables and finds the proper amount of fuel to squirt in for those conditions. It starts life with those pre-programmed values but immediately starts making modifications. Those are called the " short-term fuel trims". It puts those new learned values in memory and uses them instead of the factory programmed values. A restricted air filter, worn piston rings, vacuum leak, or slightly incorrect fuel pressure are just a few of the things that will vary among engines. The short-term fuel trim numbers are used during the rest of the drive cycle and are constantly being updated.

Over time the computer notices that it is constantly adding or subtracting fuel from the factory values. That's when it moves the short-term values into the long-term fuel trims. Every time you start the engine, it will run on those new long-term values and make short-term adjustments around them rather than the factory values. The 6.2 percent for bank two means the computer is adding 6.2 percent more fuel than was originally programmed in. That in itself might not be significant except that we are looking for a problem. Don't get " wrapped around the axle" looking for the reason this is happening while forgetting everything else, rather use that value as one part of the equation and just one potential clue. A vacuum leak will force the computer to add fuel to go with the extra air, and while bank one is adding half as much extra fuel, that implies you might need to look for a vacuum leak on one side of the intake manifold.

All fuel trim values are wiped out of memory and reset to 0 percent when the battery is disconnected or run dead. Most of the time this does not affect engine performance enough to notice, and the relearning starts taking place as soon as you start the engine.

After all is said and done, we must remember that the problem is not going to be a sensor problem if what you have is a cylinder misfire. The sensors either tell the computer some information it needs to calculate fuel metering, or they report back on what happened after the fuel was burned. They affect all cylinders equally.

Have you found the cause of the loud exhaust noise yet or whatever was sounding loud? I had a crazy thought, and I would be real surprised if this happened, but if water got up inside the transmission bell housing, what if it knocked the crankshaft position sensor out of adjustment? It is located on the right side, right behind the cylinder head, in the bell housing, and its gap is critical. Slightly too much gap and it won't develop a signal. Too small a gap and it could hit the flex plate and be broken. If you remove it, you must install a paper spacer on the end of it to set the gap when you put it back in. Some aftermarket sensors have a thin plastic rib molded on the end to set the gap. That rib partially wears away when the engine runs. You are supposed to cut the remaining rib off and use a paper spacer when reinstalling those. The dealer's parts department has the spacers. Again, don't hold your breath, but if troubleshooting shows a single plug or injector is not being fired, you might look at that sensor. You would really need to view the waveform with an oscilloscope to see the missing pulse.

If no signals come from that sensor, the Engine Computer will not turn on the automatic shutdown (ASD) relay and the engine won't run. That relay sends current to the coil(s), injectors, alternator field, O2 sensor heaters, and the fuel pump or pump relay. One or two cylinder dropouts from the crankshaft position sensor would happen way too fast for that relay to turn off. Once the sensor stops sending pulses, it takes about a full second for the ASD relay to turn off, but the missed pulse would mean a missed firing of one coil or injector.

Caradiodoc

Caradiodoc
Oct 31, 2010.
Found it! The exhaust pipe had been disconnected between the muffler and main catalytic converter.

While the engine was cool I went ahead and pulled the spark plugs to check for any problems there. All of the plugs were fine, only required minor gap adjustments. While the plugs were out I went ahead and tested the compression on each cylinder. Although doing this while the engine is cold isn't ideal, I figured it would give some valuable data if any cylinder's pressure was significantly different. All were within specifications (140-180 psi) at about 150 psi. After this, I started the engine and let it run for a bit while taking a close look at all of the exhaust components, starting with the tailpipe. I couldn't pinpoint the location of the odd sounds in the exhaust which is why I originally figured it was an engine problem. But after a few minutes I noticed a few drops of water under the middle of the exhaust pipe. Looked up and realized the joint in the pipe between the muffler and the main catalytic converter was leaking. The pipe from the cat had come out of the pipe from the muffler and the two were just resting against each other. It wasn't obvious though, I had to look very closely to see that they were not connected. At this point I turned off the engine and let everything cool overnight. The next day I loosened the pipe clamp and muscled the pipes into place. The muffler and its pipe bounced back into place and the cat's pipe slid inside. Then I repositioned the clamp and tightened it to the specified torque. I think what happened when I drove through the puddle was the deluge of water at high speed pushed on the muffler with enough force to pull it away from the cat and disconnect the pipes. With the pipes reconnected, everything sounds great! No more rough running sounds or vibration.

" Don't get wrapped around the axle looking for the reason this is happening while forgetting everything else" is great advice and I hope that anyone else who reads this takes it to heart. I was stuck on the idea that a rough sounding engine immediately after being drenched with water (and no signs of water entering the engine) must mean that some of the electronics got wet and a sensor was going bad or there was a short somewhere. I didn't even consider the fact that water could have caused physical damage to the exhaust system. Next time I'll be sure to consider all possibilities and start by looking at the first system showing signs of a problem, which in this case should have been the exhaust system and the odd noise it was making.

Thanks again for all of your help!

Tiny
2002Durango
Nov 5, 2010.
Awl right! One in a row. Happy to hear it's fixed.

Caradiodoc

Caradiodoc
Nov 5, 2010.