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From: Jeff Strickland on 19 Jan 2010 17:41

"Ray O" <rokigawa(a)NOSPAMtristarassociates.com> wrote in message
news:hj2hlm$bhc$1(a)news.eternal-september.org...
>A friend recently contacted me to ask about a check engine light on their
>2000 Windstar with 105,000 miles and to ask why the engine idles poorly and
>acts like it is going to stall unless the transmission is in neutral and
>the driver blips the throttle. Service history - replaced fuel pump 3
>years ago for a no-start condition; replaced spark plugs at 60 K miles with
>cheap aftermarket spark plugs; oil changes once or twice a year at 5,000
>mile intervals; uses about 1 quart of oil per 1,000 miles, often run 2 or 3
>quarts low on oil because oil gets checked
>
> I plugged in my handy dandy OBD II scanner and found P0171 - system too
> lean Bank 1 and P0174 - system too lean Bank 2. I know the cause, and for
> this exercise, I ask that the pros like aaracuda and claire@... NOT
> respond with the correct answer because I'm curious to see what the shade
> tree folks here come up with. Of course, the pros are welcome to respond
> with an explanation why a particular answer is correct or incorrect, IOW,
> serve as a teacher and not as a student.
>
> Here is the quiz part: What is the likely cause of P0171 and P0174? Like
> school quizzes, respondents have to explain why their answer is a likely
> cause.
>

I'm gonna start with a vacuum leak, and not rule out the brake booster.

A vac leak will allow air into the intake stream that is not being
considered by the throttle position sensor, and therefore the air is not
included in the calculations for the fuel mixture. The result being that the
mixture is lean.

The lean mixture could be reported by the O2 Sensors since the contents of
the exhaust stream would be lean and the computer would be unable to add
enough fuel to get the mixture back to expected parameters.

Since there is a lean condition on both sides of the motor, Bank 1 and Bank
2, the leak would have to be in a location that feeds both of the intake
plenums, this would include the system that makes the brake booster do it's
job. I'd expect a report that includes stalling when the brakes are applied.
If the boster itself was part of hte trouble, there should be a symptom that
is manifested with the application of the brakes. If there is no symptom
tied to the application of the brakes, then the vac line from the manifold
to the booster should be looked at.

Finally, this engine has a plastic intake manifold. It is worth
consideration that it's broken.










From: Hachiroku on 19 Jan 2010 18:34
On Tue, 19 Jan 2010 14:07:20 -0500, C. E. White wrote:

> "Hachiroku" <Trueno(a)e86.GTS> wrote in message
> news:hj4u31$v1d$2(a)news.eternal-september.org...
>
>>> The codes you listed. I had a similar situation with one of my
>>> vehicles
>>> and it came down to the intake manifold. Lean mixture and one side
>>> was
>>> leaking.
>>
>> Aw, c'mon! A Ford 3.8 with a leaking manifold gasket?!?!
>
> Better than a 3.8L with a blown head gasket!
>
> Ed

That's coming later...

From: Ray O on 19 Jan 2010 18:29

"Jeff Strickland" <crwlrjeff(a)yahoo.com> wrote in message
news:hj5chf$mkr$1(a)news.eternal-september.org...
>
> "Ray O" <rokigawa(a)NOSPAMtristarassociates.com> wrote in message
> news:hj2hlm$bhc$1(a)news.eternal-september.org...
>>A friend recently contacted me to ask about a check engine light on their
>>2000 Windstar with 105,000 miles and to ask why the engine idles poorly
>>and acts like it is going to stall unless the transmission is in neutral
>>and the driver blips the throttle. Service history - replaced fuel pump 3
>>years ago for a no-start condition; replaced spark plugs at 60 K miles
>>with cheap aftermarket spark plugs; oil changes once or twice a year at
>>5,000 mile intervals; uses about 1 quart of oil per 1,000 miles, often run
>>2 or 3 quarts low on oil because oil gets checked
>>
>> I plugged in my handy dandy OBD II scanner and found P0171 - system too
>> lean Bank 1 and P0174 - system too lean Bank 2. I know the cause, and
>> for this exercise, I ask that the pros like aaracuda and claire@... NOT
>> respond with the correct answer because I'm curious to see what the shade
>> tree folks here come up with. Of course, the pros are welcome to respond
>> with an explanation why a particular answer is correct or incorrect, IOW,
>> serve as a teacher and not as a student.
>>
>> Here is the quiz part: What is the likely cause of P0171 and P0174?
>> Like school quizzes, respondents have to explain why their answer is a
>> likely cause.
>>
>
> I'm gonna start with a vacuum leak, and not rule out the brake booster.

What symptoms would a vacuum leak normally present?

>
> A vac leak will allow air into the intake stream that is not being
> considered by the throttle position sensor, and therefore the air is not
> included in the calculations for the fuel mixture. The result being that
> the mixture is lean.

The throttle position sensor, or TPS, does not measure or consider air in
the intake steam. Basically, the TPS tells the Program Control Module
(formerly known as electronic control unit or ECU) whether the throttle
plate is open, closed, or somewhere in between.

> The lean mixture could be reported by the O2 Sensors since the contents of
> the exhaust stream would be lean and the computer would be unable to add
> enough fuel to get the mixture back to expected parameters.
>
> Since there is a lean condition on both sides of the motor, Bank 1 and
> Bank 2, the leak would have to be in a location that feeds both of the
> intake plenums, this would include the system that makes the brake booster
> do it's job. I'd expect a report that includes stalling when the brakes
> are applied. If the boster itself was part of hte trouble, there should be
> a symptom that is manifested with the application of the brakes. If there
> is no symptom tied to the application of the brakes, then the vac line
> from the manifold to the booster should be looked at.

What system makes the brake booster do its job?

There was no report of any symptom tied to the appl.ication of brakes. Does
this make the vacuum line from the manifold to the booster more suspect?

>
> Finally, this engine has a plastic intake manifold. It is worth
> consideration that it's broken.
>

There is no visible sign that the intake manifold is broken.
--

Ray O
(correct punctuation to reply)


From: Jeff Strickland on 19 Jan 2010 19:39

"Ray O" <rokigawa(a)NOSPAMtristarassociates.com> wrote in message
news:hj5ftm$8v0$1(a)news.eternal-september.org...
>
> "Jeff Strickland" <crwlrjeff(a)yahoo.com> wrote in message
> news:hj5chf$mkr$1(a)news.eternal-september.org...
>>
>> "Ray O" <rokigawa(a)NOSPAMtristarassociates.com> wrote in message
>> news:hj2hlm$bhc$1(a)news.eternal-september.org...
>>>A friend recently contacted me to ask about a check engine light on their
>>>2000 Windstar with 105,000 miles and to ask why the engine idles poorly
>>>and acts like it is going to stall unless the transmission is in neutral
>>>and the driver blips the throttle. Service history - replaced fuel pump
>>>3 years ago for a no-start condition; replaced spark plugs at 60 K miles
>>>with cheap aftermarket spark plugs; oil changes once or twice a year at
>>>5,000 mile intervals; uses about 1 quart of oil per 1,000 miles, often
>>>run 2 or 3 quarts low on oil because oil gets checked
>>>
>>> I plugged in my handy dandy OBD II scanner and found P0171 - system too
>>> lean Bank 1 and P0174 - system too lean Bank 2. I know the cause, and
>>> for this exercise, I ask that the pros like aaracuda and claire@... NOT
>>> respond with the correct answer because I'm curious to see what the
>>> shade tree folks here come up with. Of course, the pros are welcome to
>>> respond with an explanation why a particular answer is correct or
>>> incorrect, IOW, serve as a teacher and not as a student.
>>>
>>> Here is the quiz part: What is the likely cause of P0171 and P0174?
>>> Like school quizzes, respondents have to explain why their answer is a
>>> likely cause.
>>>
>>
>> I'm gonna start with a vacuum leak, and not rule out the brake booster.
>
> What symptoms would a vacuum leak normally present?
>

Well, it could make the engine run rough at idle, and the condition could go
away if the driver pressed the Go Pedal to add enough gas to balance the
extra air. Since you told me that you ran codes, I didn't bother to look
them up, I assumed you did not lie to me. System Lean would come about for a
few different reasons, but going with the cheapest first, I'm going with vac
leak.



>>
>> A vac leak will allow air into the intake stream that is not being
>> considered by the throttle position sensor, and therefore the air is not
>> included in the calculations for the fuel mixture. The result being that
>> the mixture is lean.
>
> The throttle position sensor, or TPS, does not measure or consider air in
> the intake steam. Basically, the TPS tells the Program Control Module
> (formerly known as electronic control unit or ECU) whether the throttle
> plate is open, closed, or somewhere in between.
>
>> The lean mixture could be reported by the O2 Sensors since the contents
>> of the exhaust stream would be lean and the computer would be unable to
>> add enough fuel to get the mixture back to expected parameters.
>>
>> Since there is a lean condition on both sides of the motor, Bank 1 and
>> Bank 2, the leak would have to be in a location that feeds both of the
>> intake plenums, this would include the system that makes the brake
>> booster do it's job. I'd expect a report that includes stalling when the
>> brakes are applied. If the boster itself was part of hte trouble, there
>> should be a symptom that is manifested with the application of the
>> brakes. If there is no symptom tied to the application of the brakes,
>> then the vac line from the manifold to the booster should be looked at.
>
> What system makes the brake booster do its job?
>

The vacuum system. Brake Boost is a function of vacuum.


> There was no report of any symptom tied to the appl.ication of brakes.
> Does this make the vacuum line from the manifold to the booster more
> suspect?
>

The booster can have a tear in the diaphram. My limited experience with
brake booster problems is that the engine dies when the brakes are applied
because the air that gets sucked in through the rip in the diaphram.

If the hose is the problem, then the issue would not be tied to the
application of the brakes.



>>
>> Finally, this engine has a plastic intake manifold. It is worth
>> consideration that it's broken.
>>
>
> There is no visible sign that the intake manifold is broken.


Okay, take that one off the table.

Having said that AND NOT physically observing, the manifold has been a
problem on the Ford V6, although I do not know if it's a problem with this
one.

For the record, I _think_ the Ford Windstar, Mercury Voyager, and Nissan
Quest are all related, which would make the intake on this motor a Nissan
product, not a Ford or Mazda part. I just mentioned it to cover a base.





From: Ray O on 20 Jan 2010 00:34

"Jeff Strickland" <crwlrjeff(a)yahoo.com> wrote in message
news:hj5jcp$lbe$1(a)news.eternal-september.org...
>
> "Ray O" <rokigawa(a)NOSPAMtristarassociates.com> wrote in message
> news:hj5ftm$8v0$1(a)news.eternal-september.org...
>>
>> "Jeff Strickland" <crwlrjeff(a)yahoo.com> wrote in message
>> news:hj5chf$mkr$1(a)news.eternal-september.org...
>>>
>>> "Ray O" <rokigawa(a)NOSPAMtristarassociates.com> wrote in message
>>> news:hj2hlm$bhc$1(a)news.eternal-september.org...
>>>>A friend recently contacted me to ask about a check engine light on
>>>>their 2000 Windstar with 105,000 miles and to ask why the engine idles
>>>>poorly and acts like it is going to stall unless the transmission is in
>>>>neutral and the driver blips the throttle. Service history - replaced
>>>>fuel pump 3 years ago for a no-start condition; replaced spark plugs at
>>>>60 K miles with cheap aftermarket spark plugs; oil changes once or twice
>>>>a year at 5,000 mile intervals; uses about 1 quart of oil per 1,000
>>>>miles, often run 2 or 3 quarts low on oil because oil gets checked
>>>>
>>>> I plugged in my handy dandy OBD II scanner and found P0171 - system too
>>>> lean Bank 1 and P0174 - system too lean Bank 2. I know the cause, and
>>>> for this exercise, I ask that the pros like aaracuda and claire@... NOT
>>>> respond with the correct answer because I'm curious to see what the
>>>> shade tree folks here come up with. Of course, the pros are welcome to
>>>> respond with an explanation why a particular answer is correct or
>>>> incorrect, IOW, serve as a teacher and not as a student.
>>>>
>>>> Here is the quiz part: What is the likely cause of P0171 and P0174?
>>>> Like school quizzes, respondents have to explain why their answer is a
>>>> likely cause.
>>>>
>>>
>>> I'm gonna start with a vacuum leak, and not rule out the brake booster.
>>
>> What symptoms would a vacuum leak normally present?
>>
>
> Well, it could make the engine run rough at idle, and the condition could
> go away if the driver pressed the Go Pedal to add enough gas to balance
> the extra air. Since you told me that you ran codes, I didn't bother to
> look them up, I assumed you did not lie to me. System Lean would come
> about for a few different reasons, but going with the cheapest first, I'm
> going with vac leak.
>

OK, sound reasoning.

>
>>>
>>> A vac leak will allow air into the intake stream that is not being
>>> considered by the throttle position sensor, and therefore the air is not
>>> included in the calculations for the fuel mixture. The result being that
>>> the mixture is lean.
>>
>> The throttle position sensor, or TPS, does not measure or consider air in
>> the intake steam. Basically, the TPS tells the Program Control Module
>> (formerly known as electronic control unit or ECU) whether the throttle
>> plate is open, closed, or somewhere in between.
>>
>>> The lean mixture could be reported by the O2 Sensors since the contents
>>> of the exhaust stream would be lean and the computer would be unable to
>>> add enough fuel to get the mixture back to expected parameters.
>>>
>>> Since there is a lean condition on both sides of the motor, Bank 1 and
>>> Bank 2, the leak would have to be in a location that feeds both of the
>>> intake plenums, this would include the system that makes the brake
>>> booster do it's job. I'd expect a report that includes stalling when the
>>> brakes are applied. If the boster itself was part of hte trouble, there
>>> should be a symptom that is manifested with the application of the
>>> brakes. If there is no symptom tied to the application of the brakes,
>>> then the vac line from the manifold to the booster should be looked at.
>>
>> What system makes the brake booster do its job?
>>
>
> The vacuum system. Brake Boost is a function of vacuum.
>
>
>> There was no report of any symptom tied to the appl.ication of brakes.
>> Does this make the vacuum line from the manifold to the booster more
>> suspect?
>>
>
> The booster can have a tear in the diaphram. My limited experience with
> brake booster problems is that the engine dies when the brakes are applied
> because the air that gets sucked in through the rip in the diaphram.

Think this through... what other symptom or condition would appear if there
were a tear in the diaphram that the driver would very likely notice?
>
> If the hose is the problem, then the issue would not be tied to the
> application of the brakes.
>
>
>
>>>
>>> Finally, this engine has a plastic intake manifold. It is worth
>>> consideration that it's broken.
>>>
>>
>> There is no visible sign that the intake manifold is broken.
>
>
> Okay, take that one off the table.
>
> Having said that AND NOT physically observing, the manifold has been a
> problem on the Ford V6, although I do not know if it's a problem with this
> one.

You're getting warm - if the problem is not a broken manifold, what else
related to the manifold could be the cause?
>
> For the record, I _think_ the Ford Windstar, Mercury Voyager, and Nissan
> Quest are all related, which would make the intake on this motor a Nissan
> product, not a Ford or Mazda part. I just mentioned it to cover a base.
>

The Mercury Villager (the Voyager is a Chrysler) and Nissan Quest are
related but the AFAIK, the Ford Windstar is not related to the
Villager/Quest.
--

Ray O
(correct punctuation to reply)


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