95 Hard starting no fault codes

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PerryrsbR - 27 Mar 2004 23:04 GMT

I have a 95 maxima that is very hard starting when the ambient tempature is
warm. If the air temp is cold, starts right up, if over 60 degrees very hard
starting. Once started restarts fine if restarted within a few minutes.

I figured it might be the MAP sensor but it tests good and as I said no fault
codes.

Any ideas would be helpfull.

Richard

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Steve T - 27 Mar 2004 21:07 GMT

> I have a 95 maxima that is very hard starting when the ambient tempature
> is
[quoted text clipped - 7 lines]
>
> Any ideas would be helpfull.

Might be a corroded FI temp sensor. When they get corroded, the resistance
goes up which make the FI think it's colder than it is and this won't set
any code. In warm weather can make them too rich which makes it hard to
start. We ussually replace the sensor and the connector as the plating is
gone off the terminals which caused the corrosion and will ussually
reoccure. If the sensor is easy to get to, on your own car it might be
worth cleaning both and seeing if the problem goes away. As a pro, my fix
has to last so I can't risk doing stuff like this, especially if the sensor
is hard to access.

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Steve

http://www.atlantaracing.com

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PerryrsbR - 28 Mar 2004 23:03 GMT

>Might be a corroded FI temp sensor. When they get corroded, the resistance
>goes up which make the FI think it's colder than it is and this won't set
[quoted text clipped - 5 lines]
>has to last so I can't risk doing stuff like this, especially if the sensor
>is hard to access.

Thanks Steve, I will check the temp sensor again for corrosion. I know the ECU
on trucks ( cat and cummins) will give a fault code if an over rich condition
exists, I just figured my maxima would to. Shouldn't the O2 sensor pickup the
rich condition?

Do appreciate your advice.

Richard

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Steve T - 28 Mar 2004 22:56 GMT

>>Might be a corroded FI temp sensor. When they get corroded, the resistance
>>goes up which make the FI think it's colder than it is and this won't set
[quoted text clipped - 14 lines]
> condition exists, I just figured my maxima would to. Shouldn't the O2
> sensor pickup the rich condition?

Well it will see it and just adjust the mixture once it starts. I've fixed
a bunch with this issue and they never have a code. Don't make the mistake
of thinking the computer will figure out -everything- and hand you the
answer to your problems.

Signature

Steve

http://www.atlantaracing.com

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CW - 29 Mar 2004 16:07 GMT

O2 sensors only work when they are at normal operating temperature
(ie. extremely hot). Moreover, I believe the error code for an O2
sensor will only activate if there is a problem with the sensor.
Otherwise the inputs are used to adjust closed loop A/F mix--but only
when the O2 sensors have reached normal operating temp. The first few
minutes after starting and driving the car, the preprogrammed open
loop map is being used.

CW

>> Steve
>>
[quoted text clipped - 6 lines]
>
>Richard

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