In my effort to determine what may cause my truck to run kind of rough on
COLD startups, I have been putting some new sensors on. About a month ago, I
put on a new AIS Sensor(dealer only part for $50), located on the backside
of the TB. While this did seem to smooth out 'in-drive' idle and cure the
erratic RPMs on the tach, it did nothing for the rough startup idle problem.
Today, I went to Pep Boys(they had the best price) and bought a Borg Warner
Coolant Temp Sensor, part number WT3026 for $11.99, plus tax. It is located
on the front of the manifold, close to the thermost; it is the coolant temp
sensor with 2 wires, not the coolant guage sensor with one wire(which is
also located kind of close to the t-stat). Installation was cake, 1/2"
wrench and about a minute of turning(short turns due to limited space), and
the old sensor was out. The tip was kind of corroded and looked bad compared
to the new one(124,000 mile old stock sensor), but I dont know if it matters
since the prong which sits down into the coolant is solid brass anyways. I
put the new one in, cleaned the CTS's connector and put some dielectric
grease on the terminals. I will see tomorrow morning and throughout the week
if this did anything. Remember now, I only experience rough idle during cold
startups, for the first 2-3 minutes; when it is warm out or the truck has
been ran and then restarted, idle in fine. Next sensor will be the TPS,
which is also a Borg Warner unit I have on order at Pep Boys; price without
tax is $22.99 and it will be in by Tuesday.
Rich emailed this info to me(THANKS!!) from his FSM, and I am hoping a bad
sensor or a starting-to-go-bad sensor may be causing a open/closed loop
issue:
Warm-up mode is an Open Loop mode in which the PCM receives signals from the
following inputs:
-Battery Voltage(checked and mine is perfect)
-Crankshaft Position Sensor
-Engine Coolant Temperature Sensor(replaced today)
-Intake Manifold Air Temperature Sensor
-Manifold Absolute Pressure Sensor
-Throttle Position Sensor
-Park/Neutral Switch (auto trans only)
-Air Conditioning Select/Request Signal (if equipped, and I dont have A/C)
Based on these inputs the following occurs:
* Voltage is applied to injectors with the PCM. The PCM controls sequence
and pulse width by switching on/off the ground to each injector.
* The PCM adjusts idle through the idle air control (IAC) motor and adjust
timing.
* The PCM operates the A/C thorugh the clutch relay.
* When engine reaches normal operating temperature, the PCM will begin
monitoring the O2S sensor input, and switch from Open Loop to Closed Loop
operation.
I will let everyone know how this CTS sensors works out and how the TPS also
performs. Thanks again Rich for the info.
Kyle
93 Dakota 4x4 V6
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 11:51:39 EDT