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TPS adjustment procedure (throttle mod.)

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95K views 146 replies 57 participants last post by  Acura_Kal  
#1 · (Edited)
*note: This post covers the accelerator position sensor (APS) not the throttle position sensor (TPS).

Here's a brief tutorial on my method of adjusting the APS (accelerator position sensor) on a Kia Forte.

Step 1: Gather your tools

A. Multimeter (set to DC voltage- 20 scale)
B. A pin or needle (mine have alligator clips attached to them)
C. A small phillips screwdriver

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Step 2: With the engine off, locate and remove the connector from the top of the APS sensor (attached to the left side of the throttle pedal)

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Step 3: Insert pin or needle into the third wire from the left (orange). When inserting, make sure that you stick the needle where the wire comes into the connector (the side with the yellow retainer)- not the side that plugs into the APS sensor. This is called back-probing.

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Step 4: Plug the connector back into the APS and connect the multimeter (positive to needle on APS plug and negative to a good ground).

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Step 5: Start the engine. Your multimeter should read ~ 0.78 volts (that's what mine was). If your multimeter is reading 0 volts, check your connections- you may not have a good connection with the wire inside the connector.

Step 6: Loosen the 5 screws circled in red, but don't remove the sensor ( I borrowed this pic from the original tutorial).

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Step 7: While watching the multimeter, rotate the APS until you read close to, but no more than 1.0 volts. Mine started out at 0.98 volts, but decreased to 0.94 volts as I re-tightened the screws (I feel that 0.95 volts is ideal, but 0.94 volts is close enough for me). It may also take some wiggling/ more loosening of the screws to get the voltage to change.

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Step 8: Re-tighten the 5 APS screws, holding the sensor in its new position as you tighten (voltage will drop some).

Step 9: Remove the needle from the connector.

Step 10: Put your tools away! It's time to enjoy your work! :)
 
#41 ·
Here's my suggestion to those of you having trouble. With the multimeter connected, press the gas pedal. Does the value go up? If so, you may have a bad TPS (providing it's over 1.0v at idle). If not, check the wire you're probing. KIA may use different wiring for different models, so test the other wires too.

As far as long-term troubles go, I wouldn't worry if the voltage is under 1.0v. If it's over, your service engine light may come on and you could be running a slightly advanced timing.
 
#43 · (Edited)
I'd like to try this, but will this effect the warranty?

G

Being silly....how would they know?

Being serious...No.

You are not altering anything...you are adjusting a switch. Same as if you adjust a belt that is squealing or adjusting your headlights.

If you manage to burn up your car while adjusting the APS because you forgot to turn off the ignition switch then yes, it will affect the warranty...lol.
 
#45 ·
Key switch off

I highly recommend do all of the work with the key switch OFF. Then turn the key on and retest voltage. If it needs another slight movement turn the key off to make more adjustments. Then turn back on to retest until you are satisfied.

If the voltage changes or isn't consistent when the key is on it will set the engine light. If you don't have a code reader that can scan a CAN system you will have to take it to a mechanic or dealer to reset the engine light. About $80
 
#46 ·
I highly recommend do all of the work with the key switch OFF. Then turn the key on and retest voltage. If it needs another slight movement turn the key off to make more adjustments. Then turn back on to retest until you are satisfied.

If the voltage changes or isn't consistent when the key is on it will set the engine light. If you don't have a code reader that can scan a CAN system you will have to take it to a mechanic or dealer to reset the engine light. About $80
Wow, I can't believe I forgot to include that. Yes, the engine should be off while adjusting. Has anyone tried it with the key in the "run" position with the engine off? That might prevent the service engine light issue.

You can always buy an Ultragauge to clear the SES light ;)
 
#48 ·
First, thanks a lot for this mod :) !!!

After I plugged my voltmeter to read the voltage correctly, I removed the fuel pump fuse and then turn the ignition on ... I had a reading of .77v. Then I turned the ignition switch off and loosen all the 5 screws ... Then I put the ignition on again and adjust the voltage to .93v by retighting the screws ... while doing this, you see the voltage changing constantly until you reach the end of the screws ... this is why it's practicle to have the ignition on to see the voltage reading changing while screwing. Once everything's done... plug again the fuse for the fuel pump, and start the engine. You'll see a difference of 0.02 to 0.03v. I mean that with the ignition on (engine off) I had a reading of 0.93 and with the engine on, I have 0.96. It changed a little bit.

Made this mod 3 weeks ago, and didn't get any check engine light. My only concern is that I changed my light pulley, so I think that 0.96v is too much for me , gonna try 0.88v /0.90v later on to see if It gives a difference. Is there other car owners with the light pulley changed that tried this mod ?

This was the method I used to adjust it ! Hope it can helps others those who had interrogations ... (for the fuel pump, I always remove it when I have to put the ignition switch on oftenly while doing testing-this is why in this mod, I removed it)

Sorry for my english folks !
 
#49 ·
i am wondering how to set the Multi Meter. I hooked a needle to the orange wire part and hooked up the multi meter, started the motor and every time get no reading it stays at 0.00, is my multi meter set on the wrong setting? or are my connections maybe not getting good contact? I have the multimeter set at DCV 20
 
#50 · (Edited)
I'm getting ready to do this mod soon and have a question about the multimeter too. Why can't you just put the alligator clips from the positive wire on the multimeter directly on the orange wire? Why does it need a pin or needle? I've never used a multimeter before .... ;)
 
#51 ·
Step 3: Insert pin or needle into the third wire from the left (orange). When inserting, make sure that you stick the needle where the wire comes into the connector (the side with the yellow retainer)- not the side that plugs into the TPS sensor. This is called back-probing.

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gtman55, one would rather not pierce the insulation of the wire in question so by using a pin/needle on the back of a terminal or plug, the pin/needle hits the actual metal connecting pin from the back where the wire attaches to it and your DMM connects at that point. Here's a visual:

Back-Probing Terminals — WSU
 
#52 ·
alright got that figured out. it read o.79 to 0.80. but on to the next problem. I loosened the 5 screws I believe to be the ones. and I have no idea where to "rotate" and what to rotate???? need some help here
 
#53 ·
Go back to post #1 and look at the 6th picture down...that is the switch you are looking at. There are 5 screws -- the 4 lower screws need to be loosened and the top right (5th) screw needs to be REALLY loosened or removed completely (it is a set screw). Then the switch rotates at the top -- in the picture the top is where the wire connector goes. The top will go left and right maybe 1/4". As positioned in the car you move the top to the front of the car (left) to increase voltage and to the rear of the car (right) to decrease voltage. Remember not to just position it full forward as the voltage will exceed 1.0 volts and your ECU will think you have the accelerator pedal pushed.
 
#54 ·
i finally managed to do it. First time set it to 97-98 it was really complicated to get it to stick to what i wanted it to. anyway, I drove it found little to no difference whatsoever. So i tried to set it to 94, only managing to get it at 91-92. Drove it, still I don't think I feel any difference at all.
 
#59 ·
Just did this, set it to .95 WOW What a difference! I can't believe I've been killing my ankles in traffic this entire time. Thanks for this post!

For people asking how to get their multimeters to work - get a 9 volt battery and hook it up to the clips, change the settings until the display reads 9.00 (+- .01).
 
#60 ·
Just did this, set it to .95 WOW What a difference! I can't believe I've been killing my ankles in traffic this entire time. Thanks for this post!

For people asking how to get their multimeters to work - get a 9 volt battery and hook it up to the clips, change the settings until the display reads 9.00 (+- .01).
Ouch!!! Please don't do this...the switches are micro switches and the ECU can be sensitive to large voltage inputs (it is only suposed to read a few volts at most) and you don't know what amperage you could shoot through it! I'm glad it worked for you but I don't recommend it to be done this way.

Never mind I think you are talking about adjusting your voltmeter...correct?
 
#63 ·
However, I probably just expected it to change the way it drives entirely. I.e. more like my brothers Audi a3. But maybe my expectations are to high, after all its only a Kia.
 
#66 ·
Been driving mine since originally adjusting it and no problems. Haven't read a single post about anyone having issues with this, the only one that had problems was one poster that forgot to reconnect his harness after adjusting and got a CEL/SES light...LoL!
 
#67 ·
Just did it myself yesterday, very happy with it :)
I was stalling quite alot and almost to the point of frustration, now I sit and watch my friend deal with the same thing and he's been driving his for a year :)
Top notch write up too, very concise
 
#68 ·
Here's my question. I have an SX with an automatic. From a standing start the throttle seems to have little free play. At speed though, there are times it seems like I'll press the throttle and nothing happens until I press it quite a bit more. That's when I notice a dead spot. Will this help in those situations?
 
#74 ·
This mod will help with the standing start issue -- give you more feel-of-control in relation to engine reaction to foot movement.

The at-speed problem you describe I believe is not fixable -- it is because the tranny is in high gear for the best MPG so the tranny holds it until you push the pedal more. Notice how the engine almost lugs like a manual tranny equipped car @ 40-45 MPH when the auto tranny is in 5th (or sixth) gear and you use just a little throttle...that's why the autos are now getting as good or better MPG than the manuals.
 
#77 ·
Well I certainly didn't mean to offend anyone when I used the term "only a Kia" I merely meant that it isn't at the level (yet) of other well known auto manufacturers. therefore I'd like to apologize for being rather hasty with my use of words.