At 12:50 PM 11/23/99 -0600, you wrote:
> <snip> If I am not getting an fault codes, does this mean that
> the sensors are good or that they are still within "reason" or
> "tolerance."
Probably but remember that a sensor's output is only as good as
its input(s).
> <snip> I was told that the 2 wired sensor threaded into the
> manifold goes bad often, and this would cause inaccurate
> temp readings by the computer which could make my Dak run poor,
> cause the puter would think the truck was cold when it was warmed
> up or vise versa. Is this true?
Here's an example where the sensor ouput may be aok but something in its
circuit (inputs) is causing the problem
> Any other sensors I can check easily or have checked easily?
> Crankshaft Postion Sensor? MAP? What about the TPS sensor, can it
> be cleaned or do they go bad? I wont go out of course and put all
> new sensors in my truck, just trying to pinpoint some problem areas
> and watch for things. Kyle
Here are some basics that I refer to when troubleshooting:
Coolant Temperature Sensor - tells PCM how hot the engine is so it can
richen the mixture on cold start (like a
choke) and prevent detonation when hot...
also signals when to turn on stock cooling fan
Throttle Position Sensor - monitors the %age of tb opening...tells PCM
if idling or acceleration...can cause surging
at idle and/or cruising speed when faulty
Manifold Absolute Pressure Sensor - measures manifold vacuum to calculate
engine load and airflow...once airflow
is calculated, appropriate amts of fuel
or spark advance are applied...a critical
sensor because once it fails, the system
will usually go into limp-home mode
Idle Air Control Motor - allows PCM to control idle speed
Exhaust Gas Oxygen Sensor - monitors exhaust gas' oxygen content indicating
the engine's real-time air/fuel ratio, allowing
PCM to fine-tune fule delivery and maintain
the idel air/fuel ratio ... factory type only
operate accurately in a very narrow range of the
a/f ratio scale...most accurate when readings
are around 14.7:1
Cam Position Sensor - tells PCM where cylinder 1 is in relation to TDC in
order to trigger the fuel injectors to deliver fuel
at the proper time...it's usually some type of magnetic
pickup (on ours, in the distributor)
Hope this helps a little.
Bob. Southern Ontario, Canada.
'97 Dakota CC Sport, FR, 5.2L, 3.55 SG, auto.
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