Relearn for tps? [Archive] - GrandAmGT.com Forum

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350rs
05-04-2010, 06:47 AM
Is there a relearn to do once you install a new one? I never did one on my gt but it gives me trouble from time to time. Ill look at a few different places for ideas but always good to have lots of answers to same question.

westerndragon
05-04-2010, 10:12 AM
i never did a relearn when i replaced my TPS

im not sure you have to do anything specific but drive the car i might be mistaken but i think it does it all on it's own

350rs
05-04-2010, 10:21 AM
yea what i get from some websites is that its non adjustable and is just a plug and play kind of thing. So my next step is to test it.. what kind of numbers should this thing be putting out? How im gonna test it i have not the foggiest yet, but ill consult a few places and see what they say.

westerndragon
05-04-2010, 10:26 AM
first did you buy it new and 2 im not sure about voltage # but if you can spin it with your finger it should have a spring resisting you and stop turning at about 1/2-3/4 of the way around.

my spent one spun freely and almost fell apart in my hand heh.

350rs
05-04-2010, 10:44 AM
Cant remember a spring.. But it attaches around the throttle shaft which. Has a working spring. But yes it was bought new

westerndragon
05-04-2010, 11:19 AM
the spring is inside the TPS and as long as you can turn the center of the sensor with out to much trouble it should be fine.

what is it doing when you drive?

are you trying to correct a high idle problem ?

350rs
05-04-2010, 12:41 PM
usually driving is fine. throttle response is fine even when the idle is messed up. I got out today while it was at about 2 grand, unplugged it and it dropped down to normal cool operating speeds ( first start of the day) in like 2 seconds. I replaced this thing about a year and a half ago. But its been giving me trouble since a few months after.

westerndragon
05-04-2010, 01:24 PM
have you replaced your IAC its cheap easy and it fixed my high idle when you unplug the TPS it changes a bunch of stuff and probably blasted that IAC into place

sometimes if you tap the IAC when you get the high idle it will "unstick" they get pretty gummed up over time.

the IAC manipulates a vaccuum and when its stuck in the "open" position all your PCM can do is add more fuel to fix the mix.

i HAD to fix this problem of the high idle because in the winter time if the high idle kicked in i would have trouble stopping i had to use neutral and/or kill the engine.

350rs
05-04-2010, 03:06 PM
oh yes, ive replaced it. taken it out and cleaned it multiple times. ive replaced pretty much every sensor dealing with idle. i might have to just replace it again. buger is like 50 bucks though. dammit. havent tried thumping it with anything other than my finger.

i generally pop it in neutral going down the road and turn it off and on. sometimes it works in one try, sometimes not. Tends to depend on engine temp. i get lucky most often when its above 150 or so.

westerndragon
05-04-2010, 04:07 PM
yeah mine was acting just like that the IAC valves are cheap crap and it doesnt take much to gum them up when i removed mine it had so much crap and crud i thought for a second i had the wrong part haha

when you replaced it you might have gotten a defective one...hmmm GM...defective...who woulda thought.

350rs
05-04-2010, 04:43 PM
nah this was a BWD part from my then work ( oreilly). The warranty is out on that now. my TPS is limited lifetime though. Maybe ill try and find that receipt and change them both

AaronGTR
05-04-2010, 06:25 PM
The TPS itself and it's position is not adjustable... but the PCM's reading of it's voltage signal IS and there IS a procedure for teaching the PCM what voltage corresponds to 0% and 100% throttle position. The car will NOT learn this itself just from driving.

I discovered this after installing my 65mm TB and adjusting the throttle stop so the plate closed and opened properly, but at idle my scanner was still seeing 0.7% throttle, and at WOT is was only seeing 98.8%. After doing the relearn it reads correctly. So here it is...

Turn ignition key to on (but don't start engine) and leave it for 10 seconds, then turn it off for 10 seconds.
Then push the pedal down as far as it will go, turn ignition key back to on for 10 seconds again, then turn key off, then release pedal and wait another 10 seconds.
Repeat this 2-3 times to make sure it's got it. If you have a scanner you can verify it. With the ignition on and foot off the pedal it should now read 0% throttle, then push it down and the percent should rise until you are at 99-100% at WOT position.

350rs
05-04-2010, 07:01 PM
never done that, simple enough. ill go do it now and report my findings in a few days. Thanks

350rs
05-04-2010, 07:12 PM
well immediate difference is pretty noticeable. Started and got down to 550 or so RPM immediately. It did however run pretty rough for a bit. Dont know if hitting the gas when on lets fuel into the cylinder or not. But after about 10 seconds or so it ran smooth again. I will find this again in a few days and let ya know how it came out.

Did you have to do it more than just the one session? And how did you find out about it? I searched for a hour or more and found nothing.

westerndragon
05-04-2010, 10:40 PM
cool good to know i guess i was just lucky it fixed my idle issue :-) thanks aaron

AaronGTR
05-05-2010, 03:42 PM
well immediate difference is pretty noticeable. Started and got down to 550 or so RPM immediately. It did however run pretty rough for a bit. Dont know if hitting the gas when on lets fuel into the cylinder or not. But after about 10 seconds or so it ran smooth again. I will find this again in a few days and let ya know how it came out.

Did you have to do it more than just the one session? And how did you find out about it? I searched for a hour or more and found nothing.


No, opening the throttle with the ignition on doesn't do anything except send a voltage signal to the PCM. Injector firing is based off the cam sensor signal... if the engine isn't running the cam isn't rotating... no injectors firing. :)

I found this info about the TPS learn on the DHP tuning forums. Thought I had posted it here before but I couldn't find it either so, I guess not.

350rs
05-05-2010, 06:10 PM
i didnt even think to look on here though. Duh me.. but at least you didnt find it either. so i may have asked a first time question! ha!

on a side note. no problems today either. still running tip top. Idle anyway. Had a rough start again.. im gonna pull plugs this weekend and check things out.

350rs
05-06-2010, 11:50 AM
day two and its running fine still. the rough startup was gone today.

this thread or at LEAST the answer provided by aaron should be stickied or something.

350rs
05-09-2010, 09:31 AM
still a great idle. Seems to be the trick. Why oh why didnt i ask this question a year and a half and 15 sensors ago..

Thank you again aaron, you have saved yet another GAGT from the rocket launcher.

WidbyJ
05-09-2010, 11:20 AM
Sticky This

lvemy3100
05-09-2010, 04:46 PM
No, opening the throttle with the ignition on doesn't do anything except send a voltage signal to the PCM. Injector firing is based off the cam sensor signal... if the engine isn't running the cam isn't rotating... no injectors firing. :)

I found this info about the TPS learn on the DHP tuning forums. Thought I had posted it here before but I couldn't find it either so, I guess not.

I too could have sworn you posted this before so I was actually waiting for you to post a link to the original post but I cant seem to find the post from you either...

mods please sticky this as its great info and will save many people lots of headache and money.

350rs
05-16-2010, 08:57 PM
Well. it worked and it didnt.. haha

it starts and idles fine when cold. But if i go somewhere and stop for 15 or 20 mins, come out and restart it.. its high again. However not as bad. In drive on the brake at a stop light its about 900 instead of 1200. Now i didnt buy a new TPS again. i just did the relearn on the old part. Could that be the problem?

AaronGTR
05-17-2010, 03:47 PM
Well. it worked and it didnt.. haha

it starts and idles fine when cold. But if i go somewhere and stop for 15 or 20 mins, come out and restart it.. its high again. However not as bad. In drive on the brake at a stop light its about 900 instead of 1200. Now i didnt buy a new TPS again. i just did the relearn on the old part. Could that be the problem?


Shouldn't be. As long as it's working properly and you did the relearn once, it should be all set. Of course as I said you'd need to look at it with a scanner to be sure, but it should be fine. Any further trouble should be something else like IAC valve or a vacuum leak somewhere, etc.

350rs
05-17-2010, 05:02 PM
daaaa gremlins.. i hate them. the iac is newer than the TPS and i did the correct install on that part. i havent noticed a vacuum leak unless there is something that would be intermittent vacuum??

westerndragon
05-17-2010, 05:41 PM
do the starting fluid trick on the vac lines. carefully spray the lines and if the engine revs you found it some small leaks or a crack in a line can be intermittent

350rs
05-17-2010, 05:52 PM
did that. the only reason it wouldnt work is if it somehow had a vacuum that wasnt ALWAYS there. somehow.. i dont know

westerndragon
05-17-2010, 11:25 PM
wiggle the lines as you spray them and you might get the little crack to open up....omg i think i just sounded like sik....you know what i mean haha

AleroB888
06-01-2010, 07:25 AM
The TPS itself and it's position is not adjustable... but the PCM's reading of it's voltage signal IS and there IS a procedure for teaching the PCM what voltage corresponds to 0% and 100% throttle position. The car will NOT learn this itself just from driving.

I discovered this after installing my 65mm TB and adjusting the throttle stop so the plate closed and opened properly, but at idle my scanner was still seeing 0.7% throttle, and at WOT is was only seeing 98.8%. After doing the relearn it reads correctly. So here it is...

Turn ignition key to on (but don't start engine) and leave it for 10 seconds, then turn it off for 10 seconds.
Then push the pedal down as far as it will go, turn ignition key back to on for 10 seconds again, then turn key off, then release pedal and wait another 10 seconds.
Repeat this 2-3 times to make sure it's got it. If you have a scanner you can verify it. With the ignition on and foot off the pedal it should now read 0% throttle, then push it down and the percent should rise until you are at 99-100% at WOT position.

Thanks, printed that out and put in the glovebox.

Now I noticed there is a range of adjustment on the throttle plate over which I still get a "zero" reading on the scanner for TPS%.

On my old stock TB, I can see just a bit of clearance past the the blade, but I can't remember if I had adjusted its position before. Should it be completely closed, or is there a specification for blade clearance? And I have seen some models with a pinhole through the blade, some without it.

When I monitor IAC position, I am getting anywhere from zero to ten or so for a reading at idle, in Park or cruise with closed throttle, then much higher at open throttle. Does anyone know what I should be reading on that?

AaronGTR
06-01-2010, 03:33 PM
0-10 at idle seems kinda low. Sounds like the throttle plate might still be open a tad too much so the IAC doesn't have to open far to keep the idle. I know I've read it somewhere how much IAC is normal, but don't remember exactly. I'm wanting to say it's like 20-30 is normal? I'd have to look at mine.

Anyway, with the throttle plate, I was told that basically you should adjust the throttle stop down until the point the plate closes and feels like it sticks a little bit when you open it up by hand, then back it out again a tiny bit so it opens and closes by hand freely without sticking. You should not see hardly any light around the plate when it's closed. If you see some gaps around it, or it's not closing far enough without hanging up on one side, you can try loosening the torx screws in the shaft that hold the plate in and adjust the plate position slightly. Close the plate to a point that looks good then tighten the screws back up and check the movement. Repeat as necessary until it's smooth and there are no gaps. It can sometimes take a while.

westerndragon
06-01-2010, 04:04 PM
One vote for Sticky

350rs
06-01-2010, 04:57 PM
ill put up 30 votes to that one. coulda saved me a lot of money and headache knowing that years ago.

AaronGTR
06-02-2010, 03:41 PM
I'd do it myself if I was a mod in this section. lol Jeremy sent me a PM like over a month ago saying he'd make me a mod and I haven't heard anything back yet?

350rs
08-24-2010, 07:38 AM
Hmm.. my high idle returned a few days in a row so i tried that relearn. Been about a week now with zero problems.

Does that thing "lose" memory? I dont think i did it after i did the whole engine rebuild. So it might have just still needed to be done. At least this was a free and quick easy fix this time. haha

AaronGTR
08-24-2010, 03:03 PM
Nope, once it's set it should be set. At least... I've never heard of it being reset like the fuel trims do when the battery is disconnected for a long time. It definitely won't just change on it's own though. Only way I've heard of changing it is if you do a full write or if you re-do the TPS learn procedure. Should be easy enough to check though. Just watch the gauges on a scanner and see if the throttle % is still at zero when you are idling, and it should go to 99.xx% when you floor it.

350rs
08-24-2010, 03:47 PM
well all is well now, so im not gonna mess with something that aint broke. ya know? I was just wondering what may have caused it.

350rs
08-28-2010, 02:31 PM
its back.. and its REALLY pissed this time. Its without a doubt the TPS. I started it and it immediately shot to 2500 or so. Got out and popped the hood. Unplugged the IAC, no chance. I unplugged the TPS and it went right to proper idle ( 1000 RPM give or take on cold engine). So i wonder if its something in the wiring itself? Id have to trace it back as far as i can. That whole area of the harness was hacked on pretty bad by some kind of parking lot mechanic. Im not even going to give whoever this was the dignity of being a backyard mechanic. No lights or anything though.. what would happen if i were do drive the car with the TPS unplugged all together? I revved it a bit by hand while i was there and it didnt seem to run strange at all. Which seems off to me but hey whatever.

AaronGTR
08-28-2010, 05:50 PM
You definitely can not drive it without the TPS. It's used for too many things like load calculations and such. Especially the switch over point from closed loop to power enrichment mode. With no TPS signal, the car won't know what to do.

350rs
08-28-2010, 06:43 PM
i didnt figure. It was shifting kinda strange today too. I assume the tranny uses signals from that freggin thing as well.

i see gmpartsdirect.com has them for like 38 bucks. Are they worth getting from them or just a parts store?

AaronGTR
08-28-2010, 11:38 PM
I'd say get it from wherever has the cheapest price. Are you sure it's the sensor though or is it the wiring? Have you replaced the sensor before or no?

350rs
08-29-2010, 12:47 AM
yea i have. So it SHOULD be fine. ill be checking the wiring before i get anything.

350rs
08-29-2010, 07:37 PM
Checked wiring. Its all 100%. It does have some kind of aftermarket weatherpacks though. I pulled the rubber on the pack itself, and its clean and corrosion free. So it should be fine. Gave it the ol pull test. and its holding tight. So im thinking, more so hoping, that the sensor was just " worn out " from not knowing that relearn procedure talked about earlier in the post. I did about 2 dozen starts. Not a single one of them went to a high idle. Went on a few drives and tried to duplicate what would normally cause it to be high, and its fine.

I hope this fixes this problem once and for all.

Plug
11-01-2010, 08:09 PM
Great thread guys. I just did the re learn and the idle is normal again.

Another vote for making this a sticky.

350rs
11-01-2010, 08:11 PM
:applause::applause:

i agree.

2000GAGT
01-06-2011, 05:01 PM
hey does anyone know what the voltage should be for throttle closed vs WOT vs engine idle? Im trying to pinpoint a problem that may be related to my TPS. With the car off and throttle closed its reading .5v and 4.5v at WOT. When the car is running and the throttle is closed the voltage drops around .15v. is that normal or should the voltage be the same car running vs car off?

WidbyJ
01-06-2011, 08:03 PM
Per GM Service Manual - The TP Sensor reads between 0.36-0.96 volts at idle to above 4.0 volts at Wide Open Throttle.

It looks like you're sensor is working properly, clean connectors would be the only other issue here. Recalibrating is always a good idea anyhow...

AaronGTR
01-06-2011, 10:09 PM
I would think the voltage reading from the sensor should stay the same with the engine running or not... but I can't say that is for certain. I've never tried measuring it myself to see if that is normal or not. I know voltages to some accessories can change depending on if they are drawing from the battery or the alternator.

2000GAGT
01-07-2011, 03:57 PM
So the manual does say it should be around .5v idling... cuz im getting only +.1v when the car is on and idling so i wondering if it is my TPS then.
Does anyone want to test theirs out and verify??
I ordered a new data logger since mine crapped out, hopefully this next week i can at least scan what % the PCM thinks its at.