Codifus <codifus@[EMAIL PROTECTED]
> wrote in
news:481b7fb7$0$11624$607ed4bc@[EMAIL PROTECTED]
> nucleus wrote:
>> i checked the 94 O2 sensor. it is a heated sensor. the heater
>> resistance is within spec and, upon running the motor, the
>> sensor gave readings that are within spec.
this doesn't tell you if the O2 sensor is "SLOW";taking *too long* to
respond to O2 changes,which can cause the ECM to run the motor too rich.
From what I've read,the O2S should begin switching between 0.1v and 1.0v
in
2 minutes or less after starting from cold.
>>
>> so i checked the CTS while it was warm and watched the
>> resistance increase with temp decrease, all within spec.
>>
>> these 2 sensors on the 94 apparently are working properly.
>>
>> any other suggestions?
>> ----------------------------------------------------------------------
>> ----------------
>>
>> On Apr 25, 10:45 am, codifus <codi...@[EMAIL PROTECTED]
> wrote:
>>
>>>On Apr 25, 11:27 am, Jim Yanik <jya...@[EMAIL PROTECTED]
> wrote:
>>>
>>>
>>>
>>>
>>>
>>>
>>>>Codifus <codi...@[EMAIL PROTECTED]
> wrote
>>>>innews:4811f577$0$15157$607ed4bc@[EMAIL PROTECTED]
>>>
>>>>>nucleus wrote:
>>>
>>>>>>is there some sensor, that DOES NOT set a computer code, that can
>>>>>>cause
>>>>>>the computer to run the 94 engine richer than the 96 engine?
>>>
>>>>>Yes, the O2 sensor. The main one sticking into the exhaust
>>>>>manifold. Replace it on the 94 motor. O2 sensors can get "tired"
>>>>>without tripping the computer code.
>>>
>>>>>I replace a tired O2 on my 99 Sentra and the car came alive. The
>>>>>car felt more powerful and the gas mileage went up. The original O2
>>>>>was not pulling any codes.
>>>
>>>>>Also, the coolant temp sensor gets "tired" as well. When its
>>>>>faulty, it keeps teling the computer that the engine is cold when
>>>>>it isn't so the computer keeps running the car rich.
>>>
>>>>>Now, which one to replace? The O2, because the bad CTS symptoms
>>>>>inlclude bad gass mileage AND the car runing a little cool. You
>>>>>would have noticed that your temp gage was sitting a little lower
>>>>>than normal.
>>>
>>>>>CD
>>>
>>>>I never heard of a coolant temp sensor getting "tired";all they are
>>>>is a NTC thermistor,a temp sensitive resistor. I had one go open,on
>>>>my Integra GS-R.
>>>
>>>>also,the CTS and the gauge temp sensors are separate items.
>>>
>>>>--
>>>>Jim Yanik
>>>>jyanik
>>>>at
>>>>kua.net
>>>
>>>Yup, the CTS and temp gage sensor are separate, and the CTS does get
>>>tired. Happened in my wife's Altima. Repalcing the CTS shot the car's
>>>gas mileage from an abysmall 21 right up to 27 mpg. CTS replacement
>>>is slow to adapt, it takes about 3 tankfulls for the ECU to adjust.
Or maybe you were low on coolant and the sensor was not immersed in it.
Sorry,but thermistors don't get "tired". Maybe it changed in value,skewing
the ECM map.An ohmmeter would tell.
but your comment made me think I should be checking my SpecV's CTS and
coolant level,as my mileage is a lousy 18MPG.(72K miles)
That and the primary O2S.
>>>
>>>CD- Hide quoted text -
>>>
>>>- Show quoted text -
>>
>>
> You know what? This may be by design. Looking at the history of Nissan
> engines, if you look at the SR20DE, the 91-94 version was the most
> powerfull. Why? Because that motor had faster, more aggressive cam
> profiles. Those cam profiles killed fuel economy and emissions. The
> newer SR20DE motors were less powerful but cleaner due to the milder
> cams.
>
> Something tells me your 94 Sentra has more aggrressive cam profiles in
> its GA16DE motor than the 96 Sentra. In other words, the 94 should
> feel a bit more powerful than the 96 motor.
>
> If that is what you observe than that's just the way it is.
>
> CD
>
--
Jim Yanik
jyanik
at
kua.net
|
