Throttle position sensor question

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99_Ram_2500

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i have a 99 ram 2500 and had a live data reader hooked up and noticed when the throttle is closed is says my throttle position is 13%, and when i hold the pedal to the floor it only says 74.9%. so i made sure the throttle blades were closing and opening all the way which they were. i then plugged the reader into a couple other vehicles and they all said 0% when closed and 100% at wot. so i bought a new tps and this one says 12.5% closed and 70% throttle at wot.

I then removed the new tps but left it connected to the harness and it read as 2.5% throttle, and did the same with the old and it read as 11.8%

does anybody have any idea whats going on here, ive been looking and cant find anything. any help would be greatly appreciated.
 

DodgeTx

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it is possible that your reader is not functioning properly on this truck.
 

dudeman2009

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Some of the cheaper readers don't know how to interpret the signal and will push false results.

The cheap reader I got from harbor freight a few years ago gives me the same thing. Does the same thing on fords and GMCs plus subsidiaries.

As long as the throttle plate opens and closes all the way you will be fine, the PCM has already learned the TPS.
 

MoparMagic'00

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Could easily be a stretched throttle cable..

Sent from my SM-S920L using Tapatalk
 
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99_Ram_2500

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Could easily be a stretched throttle cable..

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nope. already checked that. i hooked up another reader and got the exact same numbers again. im gonna find another 2nd gen ram and scan it to see what it says.

since the new tps my fuel milage has gone up an incredible amount.
 

Dodgeram35

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Did you ever find out the problem? I have the same exact issue
 
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99_Ram_2500

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Did you ever find out the problem? I have the same exact issue

not 100% yet, but im leaning towards the computer is bad because of the other symptoms im having too which could have something to do with the readings of the tps.
On monday im going to see if i can pick up anther computer and try it, i will let you know what happens.
 

dudeman2009

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On every vehicle i've worked on and been able to get TPS sensor readings, none of them have ever hit 0% or 100%. its designed that way. Really all a TPS sensor is, is a 3/4 turn potentiometer. The throttle plate barely makes it a full half turn. Since the pot will output between 0V-5V, you will never get a reading of 0 or 5V, because the throttle plate simply won't rotate that far. Why not use a half turn pot? Troubleshooting, thats it. Since a 3/4 turn pot will never hit the stops on either side of its travel, the computer knows that if it receives either 0 or 5V that there is a problem, since it should never see those values. If you used a half turn pot, then 5V and 0V would be common, say the pot broke or the wire was shorted to ground (0V), the computer would never know, and always think you're either flooring it, or at idle.

Based on your readings, everything is fine with the TPS. The reason you got 0-100% on some vehicles, is solely because of the data they provide. Vehicles 'learn' the TPS position at idle and WOT, thats why Dodge has the APPs reset procedure. Dodge, Chevy and Ford all (mostly) report actual sensor voltage as a percentage. Some manufacturers report the 'learned' percentage, which would show 0-100% but when looking at the voltages you'd still only see a range from about .5V to 4.5V.
 
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99_Ram_2500

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What's cyl 8 plug look like?

my number 8 looks good, my number 2 kept fowling up.
a week ago i did a pcm reset and have only used supreme fuel and since than i havent had a problem.
before i did the reset, 5 or 6 times a day it would go into misfiring spells while driving and would idle as low as 200rpm
 

99RoughCountryRam

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I've learned this the hard way Mopar and gm tbi,tpi, and mpfi you are better off buying the OEM sensors sometimes even from a boneyard than putting parts stores house brand new sensors on the vehicles and they will usually drive you nuts with problems and intermittent issues you can't explain until you do acquire the OEM sensor and fix it.
 

dapepper9

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I've learned this the hard way Mopar and gm tbi,tpi, and mpfi you are better off buying the OEM sensors sometimes even from a boneyard than putting parts stores house brand new sensors on the vehicles and they will usually drive you nuts with problems and intermittent issues you can't explain until you do acquire the OEM sensor and fix it.
Quit necroposting bro
 
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