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From: Jeff Strickland on 20 Jan 2010 12:47

"Ray O" <rokigawa(a)NOSPAMtristarassociates.com> wrote in message
news:hj65du$o2c$1(a)news.eternal-september.org...
>
> "Jeff Strickland" <crwlrjeff(a)yahoo.com> wrote in message
> news:hj5jcp$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?

The driver may or may not notice increased braking effort.

I've only seen one case of a torn diaphram, and my vague recollection was
that the driver did not notice a change in the braking effort. The symptom
was that when he applied (held the brake applied) at a traffic light, he had
to use the other foot to keep the gas up or the engine would stall.



>>
>> 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.

Villager, Voyager ... what's a few letters among friends? I can't recall why
I thought there was a relationship. I'm pretty sure the Quest has a
stablemate with a Detroit badge, but maybe not.

You said there's no sign that the manifold is broken, now you're saying that
this guess is warm? I'm confused. I would have expected the, "you're getting
warm" comment to have come earlier.

I think you said that the injectors had been replaced -- neglecting to also
replace the o-ring seals, or damaging them, would give a lean condition. I
don't know if this motor requires the intake manifold to come off for that
job, but if so, the gasket could have moved or a bolt missed or a hose left
off.


From: C. E. White on 20 Jan 2010 13:10

"Jeff Strickland" <crwlrjeff(a)yahoo.com> wrote in message
news:hj7fji$1jg$1(a)news.eternal-september.org...
>>> 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.
>
> Villager, Voyager ... what's a few letters among friends? I can't
> recall why I thought there was a relationship. I'm pretty sure the
> Quest has a stablemate with a Detroit badge, but maybe not.

In the past, the Villager and Quest were related (1993-2002). When
they were related, they were mini-vans built in a Ford owned factory
using a Nissan drivetrain (3.0 or 3.3 V6 engine / Jatco transmission).
The Quest and Villager were unrealted to the Windstar. Eventually
Nissan decided to built the Quest in their own factory and the
Villager was discontinued (2002). Mercury did sell a version of the
Windstar after the Villager was discontinuted. It was called the
Monterey and was sold from 2004-2007. The Windstar and Monterey never
used the Nissan motor. The Villager and Quest never used a Ford motor.
Winstars used 3.0L OHV, 3.8L OHV, and 4.2L OHV six cylinder engines.
The Monterey only used the 4.2L OHV engine. The 3.8 and 4.2 are
related. The 3.0L OHV engine is a version of the "Vulcan" 3.0L OHV V6
originally offered in the Taurus in 1986.

Ed


From: Ray O on 20 Jan 2010 15:50

"Jeff Strickland" <crwlrjeff(a)yahoo.com> wrote in message
news:hj7fji$1jg$1(a)news.eternal-september.org...
>
<snipped>
>>> 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?
>
> The driver may or may not notice increased braking effort.
>
> I've only seen one case of a torn diaphram, and my vague recollection was
> that the driver did not notice a change in the braking effort. The symptom
> was that when he applied (held the brake applied) at a traffic light, he
> had to use the other foot to keep the gas up or the engine would stall.
>

OK, you have described the symptoms of a torn or leaking brake booster
diaphram, but that was not one of the symptoms or conditions that the driver
in the subject vehicle experienced, so a torn or leaking diaphram should
move down or off of the list of possible causes.

IOW, when trying to figure out the cause of a particular condition or
problem, it helps to think about what symptoms appear if a particular
condition is present, and then see if those symptoms are present or not.
Asking questions is part of the diagnosis process, but in this case, I
already asked the questions and provided the necessary answers.

>
>
>>>
>>> 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.
>
> Villager, Voyager ... what's a few letters among friends? I can't recall
> why I thought there was a relationship. I'm pretty sure the Quest has a
> stablemate with a Detroit badge, but maybe not.
>
> You said there's no sign that the manifold is broken, now you're saying
> that this guess is warm? I'm confused. I would have expected the, "you're
> getting warm" comment to have come earlier.

Keep thinking it through... if the symptoms are pointing to a vacuum leak,
and the manifold and hoses appear to be OK, what else could leak?

>
> I think you said that the injectors had been replaced -- neglecting to
> also replace the o-ring seals, or damaging them, would give a lean
> condition. I don't know if this motor requires the intake manifold to come
> off for that job, but if so, the gasket could have moved or a bolt missed
> or a hose left off.
>
>

I didn't say that the injectors had been replaced, and AFAIK, they are
original. I did say that the spark plugs had been replaced. Which o-ring
seals are you talking about?

The purpose of this exercise is not really to fix the car in question
because that is done. The purpose of this exercise is to help people come
up with a logical and effective way to diagnose a problem with the skills
that one would get from taking a high school level auto-shop introductory
course.

Although a late model vehicle has a lot more sensors and stuff than a 20
year old vehicle, the basic principles have not changed. An engine still
needs air, fuel, and a source of ignition in the proper quantities and at
the proper time to run, friction materials still provide friction,
lubricants still lubricate, round parts generally rotate, a screw is still
an inclined plane, E still equals I x R, manifold vacuum should be at least
16 in hg at idle, and most electrical systems are still 12 volts.

In the interest of truthfulness, I'll disclose that after I came up with my
diagnosis, I called a friend who is a Ford Master Tech to confirm.
--

Ray O
(correct punctuation to reply)


From: Jeff Strickland on 22 Jan 2010 18:53
So, Ray, what was the cause of the Lean Condition?

Last we talked, the discussion was on the gaskets/washers for the plugs, but
since the plugs were replaced at 60k, and there are now 105k miles, I'm back
to a vacuum leak. Without the actual problem in front of me, it's difficult
to give a diagnosis without the means to check as I go.





"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.
>
> --
>
> Ray O
> (correct punctuation to reply)
>


From: Ray O on 22 Jan 2010 23:15

"Jeff Strickland" <crwlrjeff(a)yahoo.com> wrote in message
news:hjddqm$ldl$1(a)news.eternal-september.org...
> So, Ray, what was the cause of the Lean Condition?
>
> Last we talked, the discussion was on the gaskets/washers for the plugs,
> but since the plugs were replaced at 60k, and there are now 105k miles,
> I'm back to a vacuum leak. Without the actual problem in front of me, it's
> difficult to give a diagnosis without the means to check as I go.
>
I was trying to steer you towards a vacuum leak as the cause of the lean
condition. I said you were warm when you mentioned the intake manifold,
which is made of plastic because the cause was a leaking intake manifold
gasket, which happens to be a common problem in this engine.

Leaking intake manifold gaskets seem to be a common condition in engines
with platic intake manifolds.
--

Ray O
(correct punctuation to reply)
>
>
>
>
> "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.
>>
>> --
>>
>> Ray O
>> (correct punctuation to reply)
>>
>
>


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