Throttle Position Sensor , Throttle Body , TPS , Rough idle , 1uzfe
I've been going crazy looking for this and FINALLY found it.
Keywords: throttle position sensor , TPS , rough idle , hesitation , stalling , starter , throttle body ...
If you've got poor throttle response, rough idle, hesitation or were a dummy like me and took your throttle body & sensors apart. You can fix it on your own and tell the dealer where to shove their $200-500 bill.
Grab a multimeter, feeler guages, phillips (+) screw driver and in about 10 minutes your 1uzfe engine should be running like new. Two steps I would avoid from the guide however:
1. Don't remove the throttle body from the car, it's a little tight but you should be able to manage.
2. Don't remove the sensor, only loosen the screws and unclip the plugs.
If you do make this adjustment please post the results so we can help others. For example, what were your symptoms, what were the ohm readings before you made the adjustment, (the reading that caused that problem) and how did the car choke, idle and accelerate after the fix?
I'll post my "story" after I test drive the car for a few days.
OK did the adjustment myself and took a bit longer than I thought. Mainly cause the pdf has some info reversed and I wanted to test everything thoroughly so I could do a write-up. Here are 4 symptoms and solutions I came across during my testing:
Symptom: Accelerator pedal has lots of play
Solution: Remove the TRAC cover with 10mm socket. Tighten the accelerator cable, 12 or 14mm wrench. Itís the one in the back, closest to the firewall. Make sure however to leave some slack because having a tight cable is very bad. Make a small adjustment then start/stop the car after every adjustment, to test the pedal travel with your foot.
Symptom: Idle is erratic and pulses up and down, sometimes stalling the car.
Solution: Engine off. Remove the TRAC cover so you can see the gas pully 10mm socket and again it's the one in the back, closest one to the firewall. Press it down and a pin will pop up from under the right sensor. Youíll need an 8mm wrench and flathead screw driver or pliers and screw driver and perhaps a small piece of wood to jam it open so you can work. This pin is either the idle or choke adjustment, not sure which one but I know that it smoothened out my pulsating idle none the less. Note: You can tighten/loosen this pin and it will not affect the sensor what so ever. Just remember to count the turns you make in case you need to go back. Start and stop the car after every adjustment and make sure to test and adjust for both cold engine starting and warm engine starting.
Symptom: Dash TRAC light is on.
DO NOT adjust the traction control sensor, (the one farthest from the Battery) unless the TRAC light is on. If you do have to adjust it, you can actually do this one by hand through trial and error. Kill the engine, make a small adjustment and start it up. When the light goes off the sensor is set, very simple. The TRAC control does the opposite of the throttle; it actually closes up the airway or chokes the vacuum, to simulate the driver taking their foot off the pedal. Very cool.
Finally, adjusting the TPS Throttle Position Sensor:
Ignore the pdf (some info is backwards in there)
IF youíre ready to tackle the sensorís take a look at the images Iíve attached. Youíll need to rip open an old PC and find a power connector, or buy one or ask a friend. I got mine from a cpu fan. Using a utility knife shave off some of the plastic as seen in the photo. Use a sturdy knife, the plastic is hard. Although the pins in the sensor are tiny rectangles, the round power connector makes contact with them and holds tight enough to work with them. It can slide out if you pull too hard, so if the multi-meter goes funny wiggle the connector. Also make sure to face the #1, yellow wire toward the car battery.
Our yellow wire is called ďE2Ē in the pdf. Before we continue, make sure to warm up the car and if the idle rpm is low, adjust the stop pin to place get it in the desired range. Sit in the drivers seat after every adjustment and look at the rpm gauge, when you get close to where you want it, turn the engine off and on again to see the idle speed on startup. A running engine fluctuates too much and isn't accurate.
I believe the carís spec calls for 550-600 rpm idle, but Iíve seen some books say itís up to 700rpm. Start/stop the car a few more times to determine what speed is best for your old engine, to keep it running smoothly and starting smoothly. Iím at about 600-650 ish and thatís the range that keeps my car from stalling. If I go closer to 550 it struggles a bit and will sometimes choke.
Now unplug the sensor wire and plug in your connector. Place the 0.65mm feeler gauge under the stop screw. Jam the multi-meter pins into the back of the other connector so they hold themselves in. Pins go to #1 yellow and #2 black, there are numbers on the plug. Multi-meter set to continuity. Now rotate the sensor all the way to one side and all the way to the other, find the exact instant the continuity shuts off and tighten one screw. Now insert the 0.45mm and continuity should be restored. (Continuity on some multi-meters is a beep to show two items are connected. If you've never used the meter before and you want to test it, make sure not to touch the pins to each other as it could damage the unit. Touch something thatís metal instead.)
Now change to resistance mode and using the same #1 & #2 wires it should read ď0.34-6.3Ē ohms as stated in the pdf. Now change to pins #1 & #3 and insert the 0.45mm. It should read under 0.5k ohms. Note: No matter what I do, my sensor sits around 700 ohms, I might need a new one but Iíd love to compare notes with someone elseÖ
Now when you insert the 0.65mm feeler the resistance should go to infinity. On my meter it reads 0.0 Million ohms.
Thatís it, youíre done. Start and stop the car a few times to test everything out and take it for a test drive and let us know how it worked out for you.