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I am having a fit with replacing a Throttle Position Sensor on a 2004 For Taurus Duratec Throttle body. Seems simple enough right? Two bolts and a sensor plug, right there in easy reach, well… not in this case. Sure the bolt up is easy as pie, but its getting an output voltage curve when rotating the throttle that is the PITA. No matter what I do, I cant get it to work properly. Bolting it straight up, I get a .4volt reading, and will not increasing with throttle movement. I try a preload, and it is too high, actually its full throttle( 5volts) at only a tiny amount of preload.. the Sensor has two sleeved holes for bolt up with no elongation for rotation to dial in a suitable idle voltage base setting when bolted to the throttle body.
I have been on Ford Taurus Forums and got nowhere. Since I am a huge fan of Eric the Car Guy, I decided to come here.
Also, the car spent 4 days at the dealer, and even they could not find out why the car was acting the way it does. (Jerky low powered parking lot speed bucking and hesitations, that after car reach operating temperature, it does it at interstate speeds, especially when at 80% or more throttle) I have my doubts about how through the dealer was in diagnosing the car.. as anyone could have found an issue with TPS reading on a scanner and went straight to it.
Any help or suggestions is greatly appreciated. I am at the end of my rope, and the sad part is, In my former glory days, I was a Mechanic on Police Crown Victorias, and have never had one this stubborn.
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I’m sure you’ll get a more experienced reply…they don’t usually leave us chicks ‘hangin’. thank god!
*is there a resistance test you can perform on the sensor itself so you don’t have to rely on the voltage readings?
*do you have a scan tool? my low-end tool will pull MIL codes and check the ODB2 monitor readiness status
*Eric’s videos may save your butt. Maybe try ones on intake and exhaust, never know what he can teach you.
*on my Accord, (according to my Chilton) the ECM/PCM compares the TP sensor with the MAP sensor readings, and a discrepancy will cause a MIL lamp.
*how about a vehicle history? What related repairs have been done? not sure if the Duratec is the original throttle body or not.another idea – check out Eric’s g+ page, he does live question/answer every week I think. you could luck out and have him pick your question, he would outline all possibilities for this problem!
https://plus.google.com/100195180196698058780/posts
just trying to help!
The Original Throttle Body on the car is where this started, so I replaced it with one off another Taurus Vin code S engine, as the shaft impeller to rotate the TPS has become broken.. somehow. I learned this after I was tested the Factory TPS, which had 147k miles since 2003. To say the least, this car has been a real tool, and a huge drain on the bank account, continuously wanting more of my money to fix failing parts.
I have not read The resistance on the sensor, but i know after I installed it, rotating the throttle to full, I got no voltage curve whatsoever.
Before this repair, I had a new starter installed, and a flexplate, #3 Catalytic converter removed, new EGR Pressure Sensor, New EGR Valve and gaskets. This was from December to present. The other 12 months I owned it, it has had a full tune up, plugs, gaskets and a new coil pack on #1 coil. It has also had a new Oil Seal installed on the pan as well. Other than that, I believe it has had new timing belts and Serpentine belt, O2 sensor and a Water Temp sensor installed prior to my ownership. It has always had a slight stumble since i owned it, and has never went away fully.
I have not checked a MAP sensor on it, but I should state the hesitation worsens when at operating temperature, and if you turn the engine off and restart it, the symptoms are 10x worse. If it were a 4th Gen GM F-Body, it woudl have been fixed, as this make platform is my specialty, but this Taurus… is near impossible.
sounds like you already invested a TON of time and money into this.
This may be a wiring or sensor problem, or the throttle body itself, who knows. But checking related components, and ruling out intake and exhaust, which will only complicated finding the real issue, is a good start.
DO YOU HAVE ADEQUATE POWER?
(obvious) hows your battery.INTAKE
*(obvious) all the vacuum lines are solid? Is there any indication of a vacuum leak? varied idle, high-pitched noise (THANKS ERIC). do you have an inner throttle body hole you can put your finger over to test for a throttle body vacuum leak? idle should drop if so.
If potential idle or vacuum issue, hows your IACV and do you have a fast idle valve on your throttle body? People clean these and MAF sensors as well when diagnosing idle. I think there’s a specific cleaner for MAF sensors, but I wonder if you could use electrical contact cleaner on your other sensor connections.EXHAUST
*If you replaced EGR, you could have a clogged EGR passage somewhere, carbon lurking in air passages.
*if you replaced your oil pan gasket, could be clogged PCV valve causing pressure in the crankcase. I had aftermarket and it caused idle issues as well. (vacuum. THANKS ERIC)CODES
there are a ton of THROTTLE codes. Which one is yours?
P0120-P0124
P0220-P0229
that’s 15 different throttle codes, may be more. Eric has a code look-up function on his site.Not sure if a high-end code reader has the capability of monitoring your MAP, but if it’s a related system like on my car, I would check that next. Gotta wonder about possible tests for the PCM itself.
HERE’S THE DIAGNOSTIC for my accord on MAP AND TP SENSORS, you may find it interesting
MAP SENSOR TEST
1. check the connection at the MAP sensor connector
2. check the terminals within the connector for corrosion or poor contacts causing high resistance
3. repair or replace electrical connections if necessary
4. if code three is detected, an electrical problem in the system may be present
5. remove the electrical connector from the map sensor
6. turn the ignition key to the ON position
7. connect the positive lead of a voltmeter to terminal no.1, the leftmost electrical terminal
8. connect the negative probe to the terminal no.2,the middle electrical terminal harness. do not probe the MAP sensor side
9. with the volt meter connected properly, there should be a 5 volts reference signalTP SENSOR TEST
1. with engine OFF and ignition ON, check the voltage at the signal return circuit of the TP sensor by carefully backprobing the connector using a DVOM
2. voltage should be between 0.2 and 1.4 volts at idle
3. slowly move the throttle pulley to the wide open throttle (WOT) position and watch the DVOM. Voltage should slowly rise to slightly less than 4.8v at WOT.
4. If no voltage is present, check the wiring harness for supply voltage (5.0v) and ground (0.3v or less), by referring to your corresponding wiring guide. If supply voltage and ground are present, but no output voltage from TP, replace the TP sensor. If supply voltage and ground do not meet specifications, make necessary repairs to the harness or PCM.ACCORDING TO MY CHILTON, THE TP SENSOR FOR MY CAR IS A POTENTIOMETER
here’s some wiki links about those types of sensors, may help you in determining what tests are valid. If you find you can resistance test it and it passes, that’s one more item crossed off the list.http://en.wikipedia.org/wiki/Throttle_position_sensor
http://en.wikipedia.org/wiki/Potentiometer
http://en.wikipedia.org/wiki/Potentiometer_(measuring_instrument)Not sure what type of sensors MAP’s are, but for my car, the chilton says that what the MAP does, is measure and convert intake manifold vacuum into a voltage signal. The higher the vacuum, the lower the voltage signal that is sent to the ECM/PCM.
wiki link:
http://en.wikipedia.org/wiki/Map_sensorGood luck! gotta go jack my car up and GET DIRTY! now
I get good voltage at idle and reference voltage. It will not raise when throttle body shaft is rotated. I have performed every check you mentioned, new battery and a plethora of other new things. This is why the Dealer cant even figure out why it is doing what it is doing. I am wondering if the PCM is bad. The only two codes I get are misfires and TPS voltage too low. which go hand in hand since the car doesn’t know how much fuel to feed at throttle.
I had the PCM Flashed, and took it for a test drive. It kept wanting to go to first gear, parked it and found that the smallest rotation was maxing out the voltage at almost 5 volts. Warrantied out the TPS for a new one, and all is well now. it took 2 sensors to get a new one. Now, it still has the bit of jerking at a stand still in drive, but not nearly as bad as it did. I am looking into cleaning and or replacing the IAC valve next to it and see if that clears everything up.
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