RE: RE: RE: Replacing O2 sensors on 2001 3.9L V6

From: Bernd D. Ratsch (bernd@dodgetrucks.org)
Date: Thu Oct 04 2007 - 21:37:00 EDT


Common misconception is replacing the gas cap with any EVAP code....that's
not the correct way. First thing, check the lines for ANY cracks (even a
.010" crack will cause a code). Make sure the EVAP canister doesn't have
any cracks at the seams either. If all looks good, then you can change the
cap. One thing though...the EVAP system monitors do NOT run with the engine
ON...it has to be OFF and fuel level needs to be in between 15%-85%. Then,
it can take up to 1700 minutes to complete (with the engine off).

The Gas Cap code is a P0457 (2006+ models). A P0442 is a smal EVAP leak
(leak detected is from .010-.020").

- Bernd

-----Original Message-----
From: Steve Preston [mailto:steveophonic@yahoo.com]
Sent: Thursday, October 04, 2007 7:34 PM
To: dakota-truck@dakota-truck.net
Subject: Re: DML: RE: RE: Replacing O2 sensors on 2001 3.9L V6

I replaced the upstream O2 sensor (passenger side) on
my 2001 4.7 Dak in July due to an O2 sensor code. I
used a Bosch universal replacement,but I left about a
foot of the new sensor's wires (I made my connections
well away from the sensor). It took care of that
code,but I've had a P0442 code for a loose gas cap
since about a week after I changed the sensor.
Replaced gas cap with new OEM part,still have the
code. Is it possible that I'm getting a gas cap code
because of the 02 sensor not being a stock
replacement?

Thanks!

Steve P.
--- "Bernd D. Ratsch" <bernd@dodgetrucks.org> wrote:

>
> The way an O2 sensor works is this: There's either
> an air intake in the
> body, top or the sensor, or harness. Air is sampled
> through the intake and
> resistance changes. O2 sensors don't check for
> fuel...they check for air
> (O2). The harness does contain wires (obviously),
> but the clearance inside
> the harness can be "loose" to allow air to travel
> through it - four wires
> can have enough clearance in the harness for the air
> to be sampled. About
> 80% of the sensors use the body (which is why you
> don't want to get them
> caked full of mud, oil, road tar, etc).
>
> Remember: Fuel is NOT checked by the O2
> sensor....AIR is. (Lack thereof or
> abundance)
>
> - Bernd
>
> -----Original Message-----
> From: Zito, James A (GE Infra, Energy)
> [mailto:james.zito@ge.com]
> Sent: Thursday, October 04, 2007 7:53 AM
> To: Dakota list (E-mail)
> Subject: DML: RE: Replacing O2 sensors on 2001 3.9L
> V6
>
>
>
> >From Bernd:
>
> Stay away from "universal" O2 sensors that require
> you to cut/crimp your old
> connector into the new one. Reason for this is that
> the newer style O2
> sensors use the wires as an air passage for O2
> measurements. Plug it and
> you'll get either incorrect readings or a check
> engine light.
>
>
>
> HUH?? I just can't visualize what you're trying to
> say here. To paraphrase
> Curly Howard, Hey Moe them wires is full of
> copper!!! So how does air get
> down them? Also is it using this mysteriously
> penetrating air as some sort
> of a reference or what?
>
> Jim
> universal Bosch O2 sensor on his 03 Dak that is
> missing 2 pistons
>
>
>
>

       
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