1999 ford explorer idles rough when cold

When its cold (below 40 degress) my explorer will idle rough for a minuteor so, then it idles normal. I checked my fuel pressure and it is at 59 psi when it should be running between 35 to 45psi.When i pulled the vaccum line
off the fuel pulse dampner the fuel pressure stayed the same. It is throwing a code saying that it is lean or rich conditions on bank 1 and bank 2. My question would be is what could be causing this to happen? I have changed the mass air sensor,the throttle positioning sensor,the idle control sensor,the fuel pulse dampner,fuel filter,new plugs and plug wiresand oxygen sensors.help!!!!
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wrote:
|When its cold (below 40 degress) my explorer will idle rough for a minuteor |so, then it idles normal. I checked my fuel pressure and it is at 59 psi |when it should be running between 35 to 45psi.When i pulled the vaccum line |off the fuel pulse dampner the fuel pressure stayed the same. It is throwing |a code saying that it is lean or rich conditions on bank 1 and bank 2. My |question would be is what could be causing this to happen? |I have changed the mass air sensor,the throttle positioning sensor,the idle |control sensor,the fuel pulse dampner,fuel filter,new plugs and plug |wiresand oxygen sensors.help!!!!
Shotgun troubleshooting technique? No good. You can rebuild a car and not lose the alarm code. BTW, what IS the code? What is the OBDII code you're getting from your on-board computer?
Lg
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the code is 171&172 . Sorry I'm doing this for a friend , and having computer trouble at home Thanks for any help though!!!

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On Fri, 30 Jan 2004 16:42:21 -0600, you wrote:
|hi my code is 171&172 thanks for your help!!!
Hi Dale,
Whatever is measuring your lean/rich fuel mix is F.U.B.A.R.
IOW P0171 for your vehicle is: System too Lean ( Bank 1) and P0172 for your vehicle is: System too Rich ( Bank 1 )
So, there is your answer. The sensor is defective. The fuel mix sensor for bank 1, or the wiring for it, or the connector for the wiring, and so forth.
Your computer is saying the light is ON -and- the light is OFF both at the same time ( impossible ).
I don't have the repair manual for your vehicle. But you can get information ( for a FEE $$$ ) at http://www.alldata.com/products/diy/index.html
Lg
|----- Original Message -----
|Newsgroups: alt.autos.ford |Sent: Tuesday, January 13, 2004 6:34 PM |Subject: Re: 1999 ford explorer idles rough when cold | |
|> wrote:|> |> |When its cold (below 40 degress) my explorer will idle rough for a|minuteor |> |so, then it idles normal. I checked my fuel pressure and it is at 59 psi |> |when it should be running between 35 to 45psi.When i pulled the vaccum|line |> |off the fuel pulse dampner the fuel pressure stayed the same. It is|throwing |> |a code saying that it is lean or rich conditions on bank 1 and bank 2. My |> |question would be is what could be causing this to happen? |> |I have changed the mass air sensor,the throttle positioning sensor,the|idle |> |control sensor,the fuel pulse dampner,fuel filter,new plugs and plug |> |wiresand oxygen sensors.help!!!!|> |> Shotgun troubleshooting technique? No good. You can rebuild a car |> and not lose the alarm code. BTW, what IS the code? What is the |> OBDII code you're getting from your on-board computer?|> |> |> Lg Lg
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On Thu, 29 Jan 2004 20:07:02 -0600, Lawrence Glickman
|On Fri, 30 Jan 2004 16:42:21 -0600, you wrote: | ||hi my code is 171&172 thanks for your help!!! | |Hi Dale, | |Whatever is measuring your lean/rich fuel mix is F.U.B.A.R.
HO2S Heated Oxygen Sensor (two in some vehicles) upstream, 1 downstream after catalytic converter.
One of the *inputs* to the Powertrain Control Module (PCM) that adjusts short term and long term fuel trim.
ONE of the inputs to the PCM. ^^^^^
| |IOW |P0171 for your vehicle is: System too Lean ( Bank 1) |and |P0172 for your vehicle is: System too Rich ( Bank 1 ) | |So, there is your answer. The sensor is defective. The fuel mix |sensor for bank 1, or the wiring for it, or the connector for the |wiring, and so forth. | |Your computer is saying the light is ON -and- the light is OFF both at |the same time ( impossible ). | |I don't have the repair manual for your vehicle. But you can get |information ( for a FEE $$$ ) at |http://www.alldata.com/products/diy/index.html | |Lg | | ||----- Original Message -----
||Newsgroups: alt.autos.ford ||Sent: Tuesday, January 13, 2004 6:34 PM ||Subject: Re: 1999 ford explorer idles rough when cold || ||
||> wrote:||> ||> |When its cold (below 40 degress) my explorer will idle rough for a||minuteor ||> |so, then it idles normal. I checked my fuel pressure and it is at 59 psi ||> |when it should be running between 35 to 45psi.When i pulled the vaccum||line ||> |off the fuel pulse dampner the fuel pressure stayed the same. It is||throwing ||> |a code saying that it is lean or rich conditions on bank 1 and bank 2. My ||> |question would be is what could be causing this to happen? ||> |I have changed the mass air sensor,the throttle positioning sensor,the||idle ||> |control sensor,the fuel pulse dampner,fuel filter,new plugs and plug ||> |wiresand oxygen sensors.help!!!!||> ||> Shotgun troubleshooting technique? No good. You can rebuild a car ||> and not lose the alarm code. BTW, what IS the code? What is the ||> OBDII code you're getting from your on-board computer?||> ||> ||> Lg| |Lg
Lg
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On Thu, 29 Jan 2004 20:26:27 -0600, Lawrence Glickman
|On Thu, 29 Jan 2004 20:07:02 -0600, Lawrence Glickman
||On Fri, 30 Jan 2004 16:42:21 -0600, you wrote: || |||hi my code is 171&172 thanks for your help!!! || ||Hi Dale, || ||Whatever is measuring your lean/rich fuel mix is F.U.B.A.R. | |HO2S |Heated Oxygen Sensor (two in some vehicles) upstream, 1 downstream |after catalytic converter. | |One of the *inputs* to the Powertrain Control Module (PCM) that |adjusts short term and long term fuel trim. | |ONE of the inputs to the PCM. |^^^^^
BACKGROUND THEORY =================================================This monitor runs several tests by evaluating data from the heater circuit reference signals from each sensor. The upstream (precatalyst) HO2S monitor checks for high and low threshold voltage and switching frequency. Switching frequency, or cross-counts, is the number of times the signal voltage crosses the midpoint of the sensor signal range during a specific time. An HO2S monitor also evaluates sensor response by measuring the time required to perform a lean-torich and a rich-to-lean transition.
The PCM compares test results to previously stored values. Because downstream (postcatalyst) O2S voltage fluctuations are slight and the signal seldom crosses the midpoint of the range, the monitor samples voltage level under lean and rich operation.
During rich running conditions, the monitor looks for a fixed, low voltage signal from the downstream sensor.
During lean conditions, the monitor looks for downstream HO2S voltage to stay high and steady. The diagnostic executive lights the mIL to alert the driver of a malfunction if an HO2s monitor fails on two consecutive trips. =================================================== Check the wiring to your O2 sensors, Dale. And maybe the O2 sensors themselves. There is a diagnostic procedure for this.
|| ||IOW ||P0171 for your vehicle is: System too Lean ( Bank 1) ||and ||P0172 for your vehicle is: System too Rich ( Bank 1 ) || ||So, there is your answer. The sensor is defective. The fuel mix ||sensor for bank 1, or the wiring for it, or the connector for the ||wiring, and so forth. || ||Your computer is saying the light is ON -and- the light is OFF both at ||the same time ( impossible ). || ||I don't have the repair manual for your vehicle. But you can get ||information ( for a FEE $$$ ) at ||http://www.alldata.com/products/diy/index.html || ||Lg || || |||----- Original Message -----
|||Newsgroups: alt.autos.ford |||Sent: Tuesday, January 13, 2004 6:34 PM |||Subject: Re: 1999 ford explorer idles rough when cold ||| |||
|||> wrote:|||> |||> |When its cold (below 40 degress) my explorer will idle rough for a|||minuteor |||> |so, then it idles normal. I checked my fuel pressure and it is at 59 psi |||> |when it should be running between 35 to 45psi.When i pulled the vaccum|||line |||> |off the fuel pulse dampner the fuel pressure stayed the same. It is|||throwing |||> |a code saying that it is lean or rich conditions on bank 1 and bank 2. My |||> |question would be is what could be causing this to happen? |||> |I have changed the mass air sensor,the throttle positioning sensor,the|||idle |||> |control sensor,the fuel pulse dampner,fuel filter,new plugs and plug |||> |wiresand oxygen sensors.help!!!!|||> |||> Shotgun troubleshooting technique? No good. You can rebuild a car |||> and not lose the alarm code. BTW, what IS the code? What is the |||> OBDII code you're getting from your on-board computer?|||> |||> |||> Lg|| ||Lg | |Lg
Lg
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On Thu, 29 Jan 2004 20:35:49 -0600, Lawrence Glickman
|On Thu, 29 Jan 2004 20:26:27 -0600, Lawrence Glickman
||On Thu, 29 Jan 2004 20:07:02 -0600, Lawrence Glickman
|||On Fri, 30 Jan 2004 16:42:21 -0600, you wrote: ||| ||||hi my code is 171&172 thanks for your help!!! ||| |||Hi Dale, ||| |||Whatever is measuring your lean/rich fuel mix is F.U.B.A.R. || ||HO2S ||Heated Oxygen Sensor (two in some vehicles) upstream, 1 downstream ||after catalytic converter. || ||One of the *inputs* to the Powertrain Control Module (PCM) that ||adjusts short term and long term fuel trim. || ||ONE of the inputs to the PCM. ||^^^^^ | |BACKGROUND THEORY |=================================================|This monitor runs several tests by evaluating data from the heater |circuit reference signals from each sensor. The upstream |(precatalyst) HO2S monitor checks for high and low threshold voltage |and switching frequency. Switching frequency, or cross-counts, is the |number of times the signal voltage crosses the midpoint of the sensor |signal range during a specific time. An HO2S monitor also evaluates |sensor response by measuring the time required to perform a |lean-torich and a rich-to-lean transition. | |The PCM compares test results to previously stored values. Because |downstream (postcatalyst) O2S voltage fluctuations are slight and the |signal seldom crosses the midpoint of the range, the monitor samples |voltage level under lean and rich operation. | |During rich running conditions, the monitor looks for a fixed, low |voltage signal from the downstream sensor. | |During lean conditions, the monitor looks for downstream HO2S voltage |to stay high and steady. The diagnostic executive lights the mIL to |alert the driver of a malfunction if an HO2s monitor fails on two |consecutive trips. |===================================================| |Check the wiring to your O2 sensors, Dale. And maybe the O2 sensors |themselves. There is a diagnostic procedure for this. | ||| |||IOW |||P0171 for your vehicle is: System too Lean ( Bank 1) |||and |||P0172 for your vehicle is: System too Rich ( Bank 1 ) ||| |||So, there is your answer. The sensor is defective. The fuel mix |||sensor for bank 1, or the wiring for it, or the connector for the |||wiring, and so forth.
Dale,
My guess is you have 2 upstream HO2S sensors, one for Bank 1 one for Bank 2
Your Bank 1 HO2S is hosed somehow.
My _guess_.
||| |||Your computer is saying the light is ON -and- the light is OFF both at |||the same time ( impossible ). ||| |||I don't have the repair manual for your vehicle. But you can get |||information ( for a FEE $$$ ) at |||http://www.alldata.com/products/diy/index.html ||| |||Lg ||| ||| ||||----- Original Message -----
||||Newsgroups: alt.autos.ford ||||Sent: Tuesday, January 13, 2004 6:34 PM ||||Subject: Re: 1999 ford explorer idles rough when cold |||| ||||
||||> wrote:||||> ||||> |When its cold (below 40 degress) my explorer will idle rough for a||||minuteor ||||> |so, then it idles normal. I checked my fuel pressure and it is at 59 psi ||||> |when it should be running between 35 to 45psi.When i pulled the vaccum||||line ||||> |off the fuel pulse dampner the fuel pressure stayed the same. It is||||throwing ||||> |a code saying that it is lean or rich conditions on bank 1 and bank 2. My ||||> |question would be is what could be causing this to happen? ||||> |I have changed the mass air sensor,the throttle positioning sensor,the||||idle ||||> |control sensor,the fuel pulse dampner,fuel filter,new plugs and plug ||||> |wiresand oxygen sensors.help!!!!||||> ||||> Shotgun troubleshooting technique? No good. You can rebuild a car ||||> and not lose the alarm code. BTW, what IS the code? What is the ||||> OBDII code you're getting from your on-board computer?||||> ||||> ||||> Lg||| |||Lg || ||Lg | |Lg
Lg
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check the HO2S sensor on the Exhaust Manifold for Bank 1 which is the Side of the engine containing spark plug #1
The HO2S sensor for Bank 1 is screwed into the exhaust manifold. Easy does it with this. It is fragile.
Lg
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