268764 Posts in 19310 Topics - by 1565 Members - Latest Member: Jrich01

Hello Guest
Show unread posts since last visit.
Show new replies to your posts.

Author Topic: 2000 Durango P0171  (Read 2604 times)

Offline toobadq

  • Regular Member
  • Courtesy Driver
  • *
  • Posts: 44
  • My Toy
  • Awards:
2000 Durango P0171
« on: August 19, 2010, 03:36:40 am »
 I have a 2000 Durango..4.7l.... in the shop with a P0171 lean code...I have replaced the Intake gaskets, the upstream O2 (from Dodge).....I have smoked the thing looking for leaks and found none....ST fuel trim is 49% Lean...LT fuel trim is 24% Rich.....EOT is correct Map and BARO are correct....The thing runs a little rough but not bad....It pushes soot out the exh. when you mash the throttle.... Anyone got any clues....
PS....why am I working on a GAS engine? :banging:

Offline toobadq

  • Regular Member
  • Courtesy Driver
  • *
  • Posts: 44
  • My Toy
  • Awards:
Re: 2000 Durango P0171
« Reply #1 on: August 19, 2010, 02:02:46 pm »
 I have the ST and LT values backwards....ST Rich 24%....LT Lean 49%

Offline aka_chewy

  • NASCAR Crewmember
  • ****
  • Posts: 3113
  • Awards:
    Donor
Re: 2000 Durango P0171
« Reply #2 on: August 19, 2010, 02:53:38 pm »
Wow...you said a bunch of stuff I've never heard before.  Good luck with it though, hopefully someone will chime in with some knowledge

Offline toobadq

  • Regular Member
  • Courtesy Driver
  • *
  • Posts: 44
  • My Toy
  • Awards:
Re: 2000 Durango P0171
« Reply #3 on: August 22, 2010, 02:08:43 am »
 I could not find anything....think it might have E85 fuel in it....sent it home un-fixed...Im a Diesel mechanic....Gas is not what I do

Offline Parts/Service

  • Super Dave!!
  • Administrator
  • NASCAR Crew Chief
  • *****
  • Posts: 6539
  • Awards:
    MOTYDonorDistinguishedTech
Re: 2000 Durango P0171
« Reply #4 on: August 22, 2010, 02:58:55 am »
Explanation of possible cause for a FUEL SYSTEM LEAN CODE The Fuel System Lean code is set when: Short Term Compensation multiplied by Long Term Adaptive reaches a predetermined value. The actual number varies make model, but in general this will be highly positive when the condition set. Usually either short term or long term will be at +20 % or higher. The adaptives become higher when the PCM increases the injector pulse width in attempt to make the oxygen sensor switch uniformly about the PCM's oxygen sensor goal voltage. This means that the oxygen sensor is producing a voltage that is close to zero volts ( 0v ) consistently indicating a high oxygen (lean) state in the exhaust. The causes of the oxygen sensor reading a lower voltage usually falls into three main categories: 1 )Too little fuel, 2) Severe engine misfire, 3) The PCM is being provided with the improper information. THE FOLLOWING IS A GENERIC LIST OF POSSIBLE CAUSES. THE LIST IS PROVIDED AS AN EXAMPLE OF POSSIBILITIES. SOME OF THESE MAY NOT APPLY TO YOUR SPECIFIC VEHICLE. IT IS YOUR RESPONSIBILITY TO DECIDE WHICH COULD APPLY. THIS IS NOT A COMPREHENSIVE LIST : MERELY THE MORE COMMON CAUSES. 1) NOT ENOUGH FUEL -- there is an abundance of left over oxygen in the exhaust after combustion. -- This excessive could be caused by any of the following: TOO LOW OF FUEL PRESSURE-(including restricted fuel pump inlet filter, bad pump, defective pump, restricted fuel filter ) INADEQUATE FUEL VOLUME FROM FUEL PUMP ( Should deliver 1/2 liter in 7 second fuel pump actuation time) RESTRICTED INJECTORS-(both inlet screens and deposits at the injector pintle.) WRONG INJECTORS DEFECTIVE PURGE SYSTEM- (purge system is the source of a vacuum leak) 2) SEVERE ENGINE MISFIRE- although OBDII equipped vehicles have misfire detection; earlier vehicles and heavy duty truck do not. If the cylinder misfires the oxygen will simply pass through the cylinder rather than have combustion occur and the amount of oxygen in the exhaust will be high. 3) PCM IS BEING PROVIDED IMPROPER INFORMATION- If the PCM does not receive proper sensor readings it will not deliver the proper injector pulse width for conditions. The following is a list of sensor problems that could cause a fuel system lean code: COOLANT SENSOR CALIBRATION (sensor is reading much warmer than the actual engine temperature). OXYGEN SENSOR CIRCUIT PROBLEM- ( this includes O2, O2 sensor wiring including the signal, sensor ground, and heater circuit wires the O2 sensor must also be installed tight.) MAP SENSOR CALIBRATION--One of the most important readings for testing a MAP sensor is the voltage reading obtained with the DRBIII with the ignition on and the engine off. This voltage reading is important because the PCM uses this for calculating barometric pressure. If the PCM does not "know" the correct air density from the MAP sensor (baro. reading) it will have to drastically change the fuel curve through the adaptives to get the proper response from the oxygen sensor. Below is a chart of key on MAP sensor readings for a given elevation. You should get to know what is normal for your area. Elevation (feet) Baro Reading (in.-hg.) MAP voltage 0 (sea level) 29,92 4.6v 29.67 500 29.42 29.17 1000 28.92 28.67 4.4v 1500 28,42 28.17 2000 27.92 27.67 2500 27.42 4.2v 27.17 3000 26.92 26.67 3500 26.42 26.17 4.0v 4000 25.92 25.67 4500 25.42 25.17 5000 24.92 3.8v VOLTAGE SENSE-- The PCM compensates the injector pulsewidth based upon charging system voltage. The higher the voltage=> the stronger the magnetic field opening the pintle valve in the injector. The PCM compensates for this condition. If the PCM sense a higher voltage than the voltage applied to the injectors the Fuel System Rich Code could also result.

 

Questions, Concerns, Comments? Contact DOF Administrators
DodgeOwnerForums.com is not affiliated with Chrysler Group, LLC or Cummins, Inc