Yo,
TPS Replacement,same as 96.
Source: by xris @
http://www.supermotors.net/clubs/superford/registry/5183/29981#content
In 1996 Bronco/F-Series Workshop Manual, partial
http://www.diesel-dave.com/vehic/manual/stj/stjleft.htm
Section 03-14: Engine Controls, Electronic
REMOVAL AND INSTALLATION
Throttle Position (TP) Sensor
Removal
Disconnect battery negative cable.
On 5.0L and 5.8L engines, remove throttle body. Refer to Section 03-04B. On all other engines, go to Step 3.
Disconnect throttle position sensor (TP sensor) (9B989) from wiring harness.
http://www.diesel-dave.com/vehic/manual/stj/images/v10028b.gif
If reusing TP sensor, scribe alignment marks to position when reinstalling. miesk5 Note, snap a pic of how it is mounted first because there may have been a mid-year Change.
Remove two retaining screws.
Remove throttle position sensor.
Installation
CAUTION: Slide rotary tangs into position over throttle shaft blade, then rotate throttle position sensor CLOCKWISE ONLY to installed position. Failure to install the throttle position sensor in this manner may result in excessive idle speeds on 5.0L and 5.8L.
On a 5.0L and 5.8L engine, position the throttle position sensor so that the pigtail points toward the idle air control valve (IAC valve) (9F715).
NOTE: When throttle position sensor is installed on the throttle body (9E926), the connector will point toward the throttle body inlet on 4.9L and 7.5L only.
Secure throttle position sensor to throttle body with two retaining screws. Tighten to 2-3 Nm (18-27 lb-in) on 4.9L engines. On 5.0/5.8L, tighten to 1.2-1.8 Nm (11-16 lb-in).
On 5.0L and 5.8L engines, install throttle body. Refer to Section 03-04B. On all other engines, proceed to Step 4.
Connect electrical connector to harness.
Reconnect battery negative cable.
....
TSB 94-26-4
ISSUE:
The following Throttle Position Sensor (TPS) TSB has been developed for service use. This TSB includes the following topics:
• Description And Background Of TPS
• (A1) and (A2) - Diagnostic Trouble Codes (Service Tips)
• ( B) - Troubleshooting The TPS
• © - TPS Application Charts
ACTION:
If TPS diagnosis or repair is required, refer to the following procedures for service details.
DESCRIPTION
The Throttle Position Sensor (TPS) is a rotary potentiometer that provides a voltage signal to the Powertrain Control Module
(PCM) that is linearly proportional to the throttle plate/shaft angular position. The TP sensor has a three-blade electrical
connector that is plated. The plating increases the corrosion resistance on terminals and increases the connector durability. The TP sensor is mounted on the throttle body and is non-adjustable. As the TP sensor is rotated by the throttle shaft, four (4) operating conditions are determined by the PCM from the TP sensor.
The four (4) vehicle operating conditions are:
• Closed throttle (idle or deceleration)
• Part throttle (cruise, moderate acceleration)
• Wide open throttle (maximum acceleration, de-choke on crank and A/C shut-off)
• Throttle angle rate.
BACKGROUND
Recently, revisions have been made to the TPS, which have improved reliability and durability.
(A1) - DIAGNOSTIC TROUBLE CODES (DTC)
A key difference between EEC-IV, OBD I and EEC-V, OBD II is the monitors. EEC-IV monitors are designed to identify system
and component issues. EEC-V monitors are designed to measure the ability of systems and components to maintain low emission
levels.
To minimize the replacement of good components, be advised that the following non-EEC areas may be the issue:
• Excessive blow-by
• PCV malfunction
• Vacuum leaks
• Fuel pressure
• Throttle sticking or linkage binding.
EEC codes for the TPS are intended as a supplemental aid to diagnostics. They do not indicate the root cause since more than
one (1) component can set the same code.
For example: EEC-IV, OBD I Codes 122 and 123 and EEC-V, OBD II Codes P0122 and P0123 for "TP circuit too low" or "TP
circuit too high", limit the condition to the TP circuit, connector, or vehicle harness.
EEC-IV, OBD I Codes: 121, "TP inconsistent with air meter", 124, "TP higher than expected", 125, "TP lower than expected"
and
*** OBD II Code P1121, "TP inconsistent with MAF sensor" are a result of a comparison of the TP signal to a given airflow.
***Any un-metered air (downstream of MAF) that enters the engine, either due to a mechanical situation or electrical sensor condition, may result in these codes. ***
Miesk5 note, Is air tube at filter box to throttle body intact and free of cracks or holes, etc? Maf sensor must be air leak free***
PC/ED Pinpoint Tests will guide you to the root cause and avoid customer repeat repairs.
This came from
http://www.tccoa.com/articles/mn12-techinfo/tsb/tsb-94-26-4.pdf
.....
SOME CODE READERS CAN READ OBD-II PIDs (On-board diagnostics Parameter IDs), they are codes used to request data from a vehicle, used as a diagnostic tool.
P1120 - Throttle Position (TP) Sensor Out of Range Low (RATCH too Low) The TP sensor circuit is monitored by the PCM for a low TP rotation angle (or voltage) input below the closed throttle position through the comprehensive component monitor (CCM). If during key ON engine OFF or key ON engine running the TP rotation angle (or voltage) remains within the calibrated self-test range but falls between 3.42 and 9.85% (0.17 and 0.49 volt), the test fails. TP circuit with frayed wires
Corrosion on TP circuit connectors
VREF open to TP sensor
VREF short to SIG RTN
TP sensor loose pins
A TP PID (TP V PID) between 3.42 and 9.85% (0.17 and 0.49 volt) in key ON engine OFF, continuous memory or key ON engine running indicates a hard fault.
P1121 - Throttle Position (TP) Sensor Inconsistent with MAF Sensor The PCM monitors a vehicle operation rationality check by comparing sensed throttle position to mass air flow readings. If during key ON engine running self-test the comparison of the TP sensor and MAF sensor readings are not consistent with calibrated load values, the test fails and a diagnostic trouble code is stored in continuous memory.
***Air leak between MAF sensor and throttle body***
***TP sensor not seated properly***
Damaged TP sensor
***Damaged MAF sensor*** or how previous owner hacked and crammed it in the K&N, btw K&Ns are often over-oiled thereby messing up the MAF..
Drive vehicle and exercise throttle and TP sensor in all gears. A TP PID (TP V PID) less than 4.82 % (0.24 volt) with a LOAD PID greater than 55% or a TP V PID greater than 49.05% (2.44 volts) with a LOAD PID less than 30% indicates a hard fault.
If a malfunction occurs in the throttle position sensor circuit, the powertrain control module will recognize that the throttle position sensor signal is out of specification. The powertrain control module will then operate the E4OD transmission at a higher line pressure to prevent transmission damage. This high line pressure causes harsh upshift and engagements. Used as an input to determine shift scheduling and electronic pressure control.
Symptoms: Harsh engagements, firm shift feel, abnormal shift schedule, abnormal or no torque converter clutch operation. May flash transmission control indicator lamp.
Diagnostic Trouble Codes: P0121, P0122, P0123, P1120, P1121, P1124, P1125.
Air Charge Temp sensor (ACT) is mounted on driver side of filter box.
http://web.archive.org/web/20051119080559im_/http://fordfuelinjection.com/images/act.jpg
This measures the temperature of the air entering the engine. Which impacts the fuel ratio; the cooler the incoming air is the denser it is. Denser air can utilize more fuel, giving us even greater accuracy in obtaining our desired air to fuel ratio.
***
MAF Sensor:
Use MAF spray cleaner even though Ford does not recommend cleaning. See this by Dan
http://www.fordf150.net/howto/clean-maf-mass-airflow-sensor.php
This is what a Ford mechanic would do;
MAF Contamination TSB 98-23-10 by Ford for 94-96
ISSUE: This TSB article is a diagnostic procedure to address vehicles that exhibit lean driveability symptoms and may or may not have any Diagnostic Trouble Codes (DTCs) stored in memory.
ACTION: Follow the diagnostic procedures described in the following Service Tip. The revised diagnostic procedure is a more accurate means of diagnosing the symptoms.
SERVICE TIP MASS AIR FLOW (MAF) DISCUSSION
MAF sensors can get contaminated from a variety of sources: dirt, oil, silicon, spider webs, potting compound from the sensor itself, etc. When a MAF sensor gets contaminated, it skews the transfer function such that the sensor over-estimates air flow at idle (causes the fuel system to go rich) and under-estimates air flow at high air flows (causes fuel system to go lean). This means Long Term Fuel Trims will learn lean (negative) corrections at idle and learn rich (positive) corrections at higher air flows.
If vehicle is driven at Wide Open Throttle (WOT) or high loads, the fuel system normally goes open loop rich to provide maximum power. If the MAF sensor is contaminated, the fuel system will actually be lean because of under-estimated air flow. During open loop fuel operation, the vehicle applies Long Term Fuel Trim corrections that have been learned during closed loop operation. These corrections are often lean corrections learned at lower air flows. This combination of under-estimated air flow and lean fuel trim corrections can result in spark knock/detonation and lack of power concerns at WOT and high loads.
One of the indicators for diagnosing this condition is barometric pressure. Barometric pressure (BARO) is inferred by the Powertrain Control Module (PCM) software at part throttle and WOT (there is no actual BARO sensor on MAF-equipped vehicles, except for the 3.8L Supercharged engine). At high air flows, a contaminated MAF sensor will under-estimate air flow coming into the engine, hence the PCM infers that the vehicle is operating at a higher altitude. The BARO reading is stored in Keep Alive Memory (KAM) after it is updated. Other indicators are Long Term Fuel Trim and MAF voltage at idle.
NOTE: THE FOLLOWING PROCEDURE MAY ALSO BE USED TO DIAGNOSE VEHICLES THAT DO NOT HAVE FUEL SYSTEM/HO2S SENSOR DTCs.
Symptoms
Lack of Power
Spark Knock/Detonation
Buck/****
Hesitation/Surge on Acceleration
Malfunction Indicator Lamp (MIL) Illuminated - DTCs P0171, P0172, P0174, P0175 may be stored in memory
OBDII DTCs
P0171, P0174 (Fuel system lean, Bank 1 or 2)
P0172, P0175 (Fuel system rich, Bank 1 or 2)
P1130, P1131, P1132, (HO2S11 lack of switching, Bank 1)
P1150, P1151, P1152, (HO2S21 lack of switching, Bank 2)
OBDI DTCs
181, 189 (Fuel system lean, Bank 1 or 2)
179, 188 (Fuel system rich, Bank 1 or 2)
171, 172, 173 (HO2S11 lack of switching, Bank 1)
175, 176, 177 (HO2S21 lack of switching, Bank 2)
184, 185 (MAF higher/lower than expected)
186, 187 (Injector pulse width higher/lower than expected)
NOTE: DO NOT DISCONNECT THE BATTERY. IT WILL ERASE KEEP ALIVE MEMORY AND RESET LONG TERM FUEL TRIM AND BARO TO THEIR STARTING/BASE VALUES. THE BARO PARAMETER IDENTIFICATION DISPLAY (PID) IS USED FOR THIS DIAGNOSTIC PROCEDURE. ALL OBDII APPLICATIONS HAVE THIS PID AVAILABLE. THERE ARE SOME OBDI VEHICLES THAT DO NOT HAVE THE BARO PID, FOR THESE VEHICLES OMIT THE BARO CHECK AND REFER ONLY TO STEPS 2, 3, AND 4 IN THE DIAGNOSTIC PROCEDURE.
1. Look at the BARO PID. Refer to the Barometric Pressure Reference Chart in this article. At sea level, BARO should read about 159 Hz (29.91 in. Hg). As a reference, Denver, Colorado at 1524 meters (5000 ft.) altitude should be about 144 Hz (24.88 in. Hg.). Normal learned BARO variability is up to ±6 Hz (±2 in. Hg.). If BARO indicates a higher altitude than you are at (7 or more Hz lower than expected), you may have MAF contamination. If available, Service Bay Diagnostic System (SBDS) has a Manifold Absolute Pressure (MAP) sensor that can be used as a barometric pressure reference. Use "MAP/BARO" test under "Powertrain," "Testers and Meters." Ignore the hookup screen. Connect GP2 to the reference MAP on the following screen.
NOTE: REMEMBER THAT MOST WEATHER SERVICES REPORT A LOCAL BAROMETRIC PRESSURE THAT HAS BEEN CORRECTED TO SEA LEVEL. THE BARO PID, ON THE OTHER HAND, REPORTS THE ACTUAL BAROMETRIC PRESSURE FOR THE ALTITUDE THE VEHICLE IS BEING OPERATED IN. LOCAL WEATHER CONDITIONS (HIGH AND LOW PRESSURE AREAS) WILL CHANGE THE LOCAL BAROMETRIC PRESSURE BY SEVERAL INCHES OF MERCURY (±3 Hz, ±1 in. Hg.).
NOTE: BARO IS UPDATED ONLY WHEN THE VEHICLE IS AT HIGH THROTTLE OPENINGS. THEREFORE, A VEHICLE WHICH IS DRIVEN DOWN FROM A HIGHER ALTITUDE MAY NOT HAVE HAD AN OPPORTUNITY TO UPDATE THE BARO VALUE IN KAM. IF YOU ARE NOT CONFIDENT THAT BARO HAS BEEN UPDATED, PERFORM THREE OR FOUR HEAVY, SUSTAINED ACCELERATIONS AT GREATER THAN HALF-THROTTLE TO ALLOW BARO TO UPDATE.
2. On a fully warmed up engine, look at Long Term Fuel Trim at idle, in Neutral, A/C off, (LONGFT1 and/or LONGFT2 PIDs). If it is more negative than -12%, the fuel system has learned lean corrections which may be due to the MAF sensor over-estimating air flow at idle. Note that both Banks 1 and 2 will exhibit negative corrections for 2-bank system. If only one bank of a 2-bank system has negative corrections, the MAF sensor is probably not contaminated.
3. On a fully warmed up engine, look at MAF voltage at idle, in Neutral, A/C off (MAF V PID). If it's 30% greater than the nominal MAF V voltage listed in the Powertrain Control/Emissions Diagnosis (PC/ED) Diagnostic Value Reference Charts for your vehicle, or greater than 1.1 volts as a rough guide, the MAF sensor is over-estimating air flow at idle.
4. If at least two of the previous three steps are true, proceed to disconnect the MAF sensor connector. This puts the vehicle into Failure Mode and Effects Management (FMEM). In FMEM mode, air flow is inferred by using rpm and throttle position instead of reading the MAF sensor. (In addition, the BARO value is reset to a base/unlearned value.) If the lean driveability symptoms go away, the MAF sensor is probably contaminated and should be replaced. If the lean driveability symptoms do not go away, go to the PC/ED Service Manual for the appropriate diagnostics.
NOTE:
DUE TO INCREASINGLY STRINGENT EMISSION/OBDII REQUIREMENTS, IT IS POSSIBLE FOR SOME VEHICLES WITH MAF SENSOR CONTAMINATION TO SET FUEL SYSTEM DTCs AND ILLUMINATE THE MIL WITH NO DRIVEABILITY CONCERNS. DISCONNECTING THE MAF ON THESE VEHICLES WILL, THEREFORE, PRODUCE NO IMPROVEMENTS IN DRIVEABILITY. IN THESE CASES, IF THE BARO, LONGFT1, LONGFT2, AND MAF V PIDs INDICATE THAT THE MAF IS CONTAMINATED, PROCEED TO REPLACE THE MAF SENSOR.
After replacing the MAF sensor, disconnect the vehicle battery (5 minutes, minimum) to reset KAM, or on newer vehicles, use the "KAM Reset" feature on the New Generation Star (NGS) Tester and verify that the lean driveability symptoms are gone.
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: INFORMATION ONLY
***
I will get to the other codes later
