absolute throttle position
04-28-2009, 06:05 PM
#1
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absolute throttle position wondering what this should be at when the car is sitting at idle, foot off the gas.
had the car tuned a few months ago and it idled great.
did some clean up/visual mods to the engine bay (painted VC, cleaned up PCV).
suddenly i was getting a high idle, and a hanging idle when coming to a stop on the road (at lights).
realized i must have bumped my TB idle screw since the idle never dropped below 1100rpm.
turned the idle screw a little bit and it idled like it should.
although i'm still getting some hanging idle. i figure i basically have to get the idle retuned since i have no idea where the screw was set compared to now.
plugged in my scan software and saw that the "absolute throttle position" was 0.4%
does this mean i've got it open too much? it idles right around 900rpm. should that reading be 0.0?
had the car tuned a few months ago and it idled great.
did some clean up/visual mods to the engine bay (painted VC, cleaned up PCV).
suddenly i was getting a high idle, and a hanging idle when coming to a stop on the road (at lights).
realized i must have bumped my TB idle screw since the idle never dropped below 1100rpm.
turned the idle screw a little bit and it idled like it should.
although i'm still getting some hanging idle. i figure i basically have to get the idle retuned since i have no idea where the screw was set compared to now.
plugged in my scan software and saw that the "absolute throttle position" was 0.4%
does this mean i've got it open too much? it idles right around 900rpm. should that reading be 0.0?
04-28-2009, 07:20 PM
#2
I was doing some research on a problem I posted from a different thread and think I found the answer for both of our questions. Post 5 and 6 should help you out: https://ls1tech.com/forums/pcm-diagn...w-voltage.html
04-28-2009, 07:50 PM
#4
My bad, I just noticed that. After doing more research, I found about two dozen threads that may ring a bell for you: https://ls1tech.com/forums/search.php?searchid=7543769
Hope this helps..
Hope this helps..
04-28-2009, 08:30 PM
#5
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just played around with my scanning software, had to update some files.
now i can look at both TP% and TP Voltage.
it was still doing the hanging idle but WOULD finally come down to ~900rpm.
however the scanner showed the TPV to be 0.75V. i played with the idle screw to try and get it closer to 0.6V, but was having trouble. turns out i think there was too much tension on the throttle cable, preventing the throttle cam from returning to full 0.
loosened the cable and was able to get the screw adjusted to a solid 0.6V.
pulled the TPS plug and turned the ign on for a min to reset the sensor, and now the TP% reads 0.0% and the voltage is 0.61.
i have a feeling its not gonna idle for **** tomorrow.
it was tuned 3 months ago and had a rock solid idle, both sitting still and after coming to a stop.
but recently i cleaned up the engine bay, and in the process i cleaned up the PCV hoses. i have a feeling i had a hole in the PCV and when i cleaned em up (better routing) i inadvertently fixed the problem.
and since it was tuned to run with that unmetered air, now that i've got it all plugged up the way its supposed to be...its gonna be starved for air.
i'm thinking thats why it would only idle with the throttle cracked a little...it needed more air.
i guess one thing to try is to pull the PCV inlet hose off. if it runs better...maybe that is my solution.
tomorrow will tell
all this was done with the engine NOT RUNNING. since its 9pm and the neighbors don't enjoy the sound a a True-Dualed Cammed v8 as a goodnight lullaby.
now i can look at both TP% and TP Voltage.
it was still doing the hanging idle but WOULD finally come down to ~900rpm.
however the scanner showed the TPV to be 0.75V. i played with the idle screw to try and get it closer to 0.6V, but was having trouble. turns out i think there was too much tension on the throttle cable, preventing the throttle cam from returning to full 0.
loosened the cable and was able to get the screw adjusted to a solid 0.6V.
pulled the TPS plug and turned the ign on for a min to reset the sensor, and now the TP% reads 0.0% and the voltage is 0.61.
i have a feeling its not gonna idle for **** tomorrow.
it was tuned 3 months ago and had a rock solid idle, both sitting still and after coming to a stop.
but recently i cleaned up the engine bay, and in the process i cleaned up the PCV hoses. i have a feeling i had a hole in the PCV and when i cleaned em up (better routing) i inadvertently fixed the problem.
and since it was tuned to run with that unmetered air, now that i've got it all plugged up the way its supposed to be...its gonna be starved for air.
i'm thinking thats why it would only idle with the throttle cracked a little...it needed more air.
i guess one thing to try is to pull the PCV inlet hose off. if it runs better...maybe that is my solution.
tomorrow will tell
all this was done with the engine NOT RUNNING. since its 9pm and the neighbors don't enjoy the sound a a True-Dualed Cammed v8 as a goodnight lullaby.
04-28-2009, 11:19 PM
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Don't sit there and worry about the voltage seen at the sensor. It is much more important for the car to idle. I don't buy the BS about it having to be between .4-.6V. If you did the reset procedure, the computer doesnt give a **** about what the voltage is anyway. All you want to make sure is it reads 0% at 0% and 100% at 100%. If you find it won't idle, don't worry about raising the TPS voltage up some, just screw up the blade til it acts like it did. Make sure you do the tps reset after each move or it might start reading into a non-idle table, and mess you all up as far as trying to dial it in.
