"Jinks" <Jinks@[EMAIL PROTECTED]
> wrote in message
news:f0hmq39h80eisqn9m8mjviv6d3su9to1sr@[EMAIL PROTECTED]
> On Thu, 07 Feb 2008 17:03:08 GMT, "Jeff Strickland" <crwlr@[EMAIL PROTECTED]
>
> wrote:
>
>>The CODE tells you which sensor is flaky.
>>
>>There is a code for each Bank 1, Sensors 1 & 2, and for each, Bank 2,
>>Sensors 1 & 2.
>>
>>Bank 1 Sensor 1 is the bank that contains exhaust from Cylinder 1, Bank
1
>>Sensor 2 contains the exhaust from the other three cylinders. Bank 2,
>>Sensor
>>1 is the CAT that has processed exhaust from the pipe that contains
>>exhaust
>>from Cylinder 1, Bank 2, Sensor 2 is the CAT that contains exhaust from
>>the
>>other three cylilnders.
>>
>>The CODE will tell you specifically which sensor is tossing up an error.
>>Give us the Code you are getting, and we can tell you which sensor is
>>toast.
>>
>>You can extract the code(s) with a OBD II scan tool, there is no need
for
>>any specialized BMW tools. The OBD II data ****t lives along the bottom
>>edge
>>of the dash board, either clearly visible OR hidden behind a small cover
>>that is clearly marked -- I believe BMW puts the ****t behind a small
cover
>>and marks it as the data ****t. (The OBD II spec. requires the data ****t
to
>>be easy to find, so you do not need to spend more than about 5 seconds
>>looking for it. Start your search near where your left leg rests while
you
>>are driving.)
>>
>>The Code for the Bank 1 sensors can be MALFUNCTION, TOO RICH, or TOO
THIN,
>>(3 separate codes, one for each condition) or a Code related to the
>>failure
>>of a heater that lives inside of the sensor itself. I forget the Code
>>options for the Bank 2 sensors, but they will translate to the CAT being
>>ineffective. There is a chance the CAT is dead, but a far better chance
>>that
>>the sensor is bad. I have never had a CAT go bad in all my years of
>>driving
>>cars with CATs in them. That is not to say that a CAT can not fail
because
>>they can, but it is rare and under normal cir***stances the
owner/operator
>>of the vehicle has introduced fuel that is not suitable. (One must
search
>>out unsutiable fuel, so the odds of this are very low and the effect is
>>very
>>rapid so you would remember the event it it occurred.)
>>
>>There can be multiple codes for any sensor, so a problem can percolate
>>through the computer in different ways. If you have a code for Bank 1
>>Sensor
>>1 and Bank 2 Sensor 2, odds favor only one of them being bad, and the
>>other
>>re****ting an out of spec condition that comes from the first in the
stream
>>not working right. If Bank 1 Sensor 1 mis-detects the fuel mixture, and
>>adjusts the Fuel Injector Timing to cause more or less fule to be
>>delivered,
>>the result can be that what flows past Bank 1 Sensor 2 is out of spec.
In
>>this instance Bank 1 Sensor 2 is okay, and only Bank 1 Sensor 1 is
giving
>>you trouble. If Bank 2 Sensor 1 (or Sensor 2) is throwing a fault in
>>isolation, then the sensors at Bank 1, Sensor 1 and 2 are working okay
and
>>do not need attention.
>>
>>Basically, replace the sensor closest to the engine (as the exhaust
flows)
>>first to see if it resolves a false re****t from the next sensor
>>downstream.
>>If the downstream sensor is throwing a code, but the upstream sensor is
>>not,
>>then do not replace the upstream sensor.
>
> Jeff,
> Sorry for not snippin' any of your reply, but I didn't want to miss
> quote anything.
> I think I followed most of what you wrote except for the second
> paragraph about Bank/sensor/cylinder relation****p. It appears to me
that
> you
> are talkin' about a 4 cylinder (318) rather than the 6 in my 328. Am I
> correct
> or have I misunderstood?
>
I think you misunderstood. The exhaust header/manifold is split, there are
two sets of three tubes that collect the exhaust from the cylinders. Bank
1
Sensor 1 is mounted to the exhaust manifold that connects to Cyl #1. I
don't
recall which other cylinders it connects to, but it really doesn't matter
for this discussion. Bank 1 Sensor 1 sniffs the exhaust coming from the
****tion of the exhaust that contains Cyl. 1, Bank 2 Sensor 2 sniffs
exhaust
that comes from the remaining bank. (Bank is a poor term because the motor
is an inline and Bank generally refers to the cylinder heads on a V-motor.
Having said that, bank is all we have, and the exhaust manifold is split
so
that it collects from two sets of three cylinders so the term works, if a
bit inelegant.)
> If it's any help the codes it's throwin' are as follows:
>
Proper etiquette is to give the full code, P0233, P0202, P0203, P0234. In
the instance where the codes are all in the same family, you can use the
shorthand, P0202, 203, 233, and 234. You did okay, but there could be a
P1202, and then your use of only the last 3 digits could be misleading.
I'm not sure where you got your information from, but the codes you gave
me
are completely different from the description.
Try this link,
http://autorepair.about.com/od/obdcodedatabase/a/OBD_1996_year.htm
> 233 = Cat. sys efficiency Bank 1
>
> 202 = Lambda control stop Bank 1
>
> 203 = Lambda control stop Bank 2
>
> 234 = Cat. sys efficiency Bank 2
>
Given this information -- which I think is wrong but for the sake of
example, I'm going to go with it for the moment -- I would replace
something
upstream from the sensors. Frankly, I'm not sure what to replace, but here
is my theory.
The CAT effeciency codes say that the crap coming out of the CAT is not
within spec, therefore the CAT is bad or the sensors are bad. BUT, the
Lambda sensors up stream are also re****ting the contenst of the exhaust as
being out of spec. This means that the crap GOING INTO the CAT is beyond
what the CAT can deal with, therefore the crap coming out of the CAT is
reasonably dirty, and any re****t of being dirty is understandable. The
sensors AFTER the CAT make an assumption about what should come out based
on
that which went in. But, what went in was more than the CAT can clean, so
the reoprt that what comes out is dirty is actually a good re****t. Bottom
line here is that you should not need to replace the CAT or the sensors
that
are mounted downstream. Your issue is entirely upstream from the CATs.
The Codes P0202 and P0203 are telling you that the fuel mixture is out of
spec, I assume TOO RICH, and can't be made any leaner through adjustments
that the computer is able to affect -- the computer can adjust the
Injector
ON Time to affect a change to the air/fuel mixture, but due to reasons
elsewhere in the system, the computer can't do its job properly and the
P0202 & 203 re****ts are simply telling you this.
My guess is that your O2 Sensors, all 4 of them, are actually working
right,
and something in the Fuel Delivery System is running amok causing a TOO
RICH
condition that the sensors are properly re****ting.
Conversely, you could have a vacuum leak that is causing a TOO LEAN
condition, but I would not expect TOO LEAN to be something the After CAT
O2
Sensors would care about -- if the mixture was lean, then it would lack
fuel
and therefore it would be clean by definition, and the CAT should be
re****ted as working well; which is cause to not re****t a Code.
I think you have a TOO RICH condition that is properly re****ted by the
Codes
P0202 and P0203, and the resulting exhaust stream that exits the CAT is
also
TOO RICH and the P0233 and P0234 codes are also accurate.
Having said all of that, review the link I gave you because the codes you
supplied should iron out to INJECTOR MALFUNCTION on #2 and #3 cylilnders,
and the P0233 and P0234 codes indicate some kind of Fuel Pump problem and
an
Overboost Condition from the turbo charger, respectively.
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