BlackDuk98

iTrader: (34)

Well for some reason I never thought at all that the TPS needed any type of adjustment. It was brought to my attention when I mentioned an on TPS dtc that I get maybe 1 time a year. I was asked if I ever adjusted it and I honestly never knew that you could.

I have read the few post I could find on this subject and all were being discussed about doing it in regards to tuning software and needing to change IAC values. Unfortunately I know nothing about tuning and cannot do this on my own. As of a few months ago, my car was tuned when I swapped to a Fast 92/92, GM 85mm MAF and a FTP 98mm lid. Unfortunately the idle part couldn't be done due to my throttle blade sticking and the car would not idle where it was commanded to. I fixed this problem multiple times and now it's fixed for good.

Since the idle has never been fixed yet, can I adjust the TPS and it still run decent? If my numbers are correct, reference voltage should be .5v and WOT should be 4.7v. I tested this with a volt meter since that is all I have and my range was .62v closed, and 5.07v WOT. From what I see, I should be able to change this with the idle screw. I read how to make the car learn this by changing the idle screw w/ the key in acc., unplugging the sensor and running the car a few mins so there is no reading, then turn the car off and plug it back in and let the car idle for a few mins so the pcm will learn the new closed voltage.

Do I have this thought out correctly? I am just trying to get my car to run correctly, been a long time since it has and I cannot do much but be at the nercy of whomever tunes my car.

any insight into this is greatly appriciated.

Thanks

mark jr.

sreve

iTrader: (3)

You need to get the wot volts down.
remove the tps and break off the locating tab and slot
the mounting holes. You can not fix wot with the idle screw.

BlackDuk98

iTrader: (34)

So slot the 2 holes until I get WOT value down to 4.7v? I just want to verify that I have the correct voltage to correct to. Should I adjust the set screw to change idle down to .5v ref, or leave it where it's at (.62v)?

Thanks for the info

mark jr.

MUSTANGBRKR02

iTrader: (91)

Why not back out the idle screw? You need to get someone to data log the car and set the throttlebody up.

jimmyblue

iTrader: (11)

I'd start with the mechanical wrongness of the TB, and
see if getting it to seat clean and not stick, lets the TPS
get to the right voltage, enter idle mode and learn itself
right as far as IAC / airflow. Certainly it's bad to try and
tune around a wrong mechanical condition.

BlackDuk98

iTrader: (34)

I have the blade sticking problem solved. the .62v closed and 5.07v WOT is the numbers with the mechanical problem solved.

I know the throttle body should be data logged and set up, but the person who I have do it doesn't do what he says he will when he says he will do it. I have tried multiple times and it never gets done. That is why I contacted another shop, but w/ e-mails not returned, and no call back, I am SOL at the moment and trying to do what I can myself. That is why I was seeing if I can correct some of the problem with getting the TPS adjusted to the correct parameters. So it sounds like I should leave it alone and wait till I can get someone who can actually look at all the info?

I need to learn this **** so I don't have to rely on others for tuning. I do every other aspect of my car and pride myself on knowing that nobody else has ever wrenched on it except tuning.

If you think I should go ahead and adjust what I can w/ hole oblonging and a volt meter I will, if not, I will wait it out and hope

thanks for the responses.

mark jr.

MUSTANGBRKR02

iTrader: (91)

If you can't do it right....

Buy HPT or EFI and get to work

mrvedit

With the throttle closed, a voltage of less than .25V will give you a DTC.
If you have any TPS related DTC, the PCM will ignore the TPS signal which will adversely affect the Dynamic Fuel/Air calculations (giving you a lean stumble on rapid throttle opening) and will not lock-up the torque converter.

jimmyblue

iTrader: (11)

Check the limit screw (or maybe there's just a hard
bump stop) against your blade angle. Blade has no
need to draw over center, at center should produce a
proper TPS voltage (4.70 or lower; >4.75 is fault range).

BlackDuk98

iTrader: (34)

MUSTANGBRKR02, I would love to do it right, but don't I need to do the physical aspect first before any tuning should be done?

There is just a hard bump stop to limit the amount the blade can open. I will look tomorrow and see if I can add a screw to limit that to open to 4.7v max.

Now I can make the blade close more because there is a screw that I can adjust to. If the current. 62v reading is good, I will leave that alone. I will snap a pic of the throttle body tomorrow to show how it is set up.

If I remember correctly, the code was a po121. Had that occur 1 time in the last 6 months and no adjustment has been done the the throttle body before. Tranny is no longer computer controlled do to it being a vacuum modulated th400 now.

MUSTANGBRKR02

iTrader: (91)

You can't adjust it if you can not set the throttlebody up properly.

You should not need to add anything to the throttle stop. The throttle body upper limit should come down when you bring the low side down.

BlackDuk98

iTrader: (34)

You're right on not needing to add to the throttle stop. I wasn't picturing it right. Now with 4.7v the WOT limit, and .25v setting a DTC, can I back the screw off enough to keep w/in the correct parameters? I would need to back the knock off .37v at WOT, which would bring the closed voltage down to .24v and set a code. Assuming I did this physically w/out software.

Now are you saying this can be done completely w/ tuning software, or does it need the physical aspect in conjunction with tuning to adjust all the other parts that can be affected by turning the screw?

I apologize for all these questions, just trying to understand this fully. I appriciate the help

mark jr.

BlackDuk98

iTrader: (34)

Well it's going to a shop Tuesday and will be taken care of then correctly. i was messing with it with a volt meter to get the voltage numbers in the range and it wouldn't work right. I can turn the screw and get the closed voltage down to .29v but this made the blade stick badly. So I loosened the blade screws thinking it needs to be able to be adjusted into it's new position. Well, cap screw rounded out so I had to use an easy out to remove it, re-sanded the blade, etc. and just adjusted it with no blade at all. Odd thing about my readings, I can knock it down to .27-.29 easily, but WOT would not go down in relation to the closed value going down. It stayed right at 5.07v. I found this odd and ended up putting it all back together and setting the idle screw back to .62v. confused.

Anyway, getting the tune finished and will see how it goes. After all of this I will be reading and lurking here for as much info as possible so I can do my own tuning and stop paying / relying on others.

I appreciate all of your help

mark jr.

Bigtoyz

iTrader: (2)

might be a bad tps....think low side is around 0.067 and WOT is 4.7

mrvedit

Jimmy: Are you sure that >4.75 volts gives a fault? I read a repair thread saying that 4.5 to 4.9V is normal for WOT. Could not find the max voltage allowed.
For closed throttle I did confirm that 0.2V gave a fault and 0.27V did not.

jimmyblue

iTrader: (11)

>4.75 for 10 seconds is what I recall from the shop manual,
to set a code; but >4.75 at all, will cause some fault actions
meanwhile (like short shifting).

djfury05

iTrader: (30)

Sounds like a faulty TPS sensor if your making all those adjustments and no changes occur. I can turn my set screw a 1/4-1/2 turn and it will show changes in the hundreths value, doesn't take much.

mrvedit

Jimmy: Thank you for the confirmation.

sreve

iTrader: (3)

It's a rheostat thats it. Changing it on the idle side won't
do squat for the WOT. Even a stock throttle body does not open 100%
when you grind the bump stop for 100% opening it will go over voltage
to remedy this break the locating tab off the TPS and slot the mounting holes
to adust it to 4.6v. At over voltage even if it does not trip a code the seat of the
pants o meter can tell that the car runs better @ 99% throttle than WOT
adusting the voltage will cure that. I want all its got a full 90* opening.
One other thing is it would be a good idea to check the voltage with a scan tool
it could be something very differnt than a volt meter. I found that what a scanner reports vs a Fluke 87 are two differnt things on an O2sensor

BlackDuk98

iTrader: (34)

I started messing with this tonight for a bit with the volt meter and the numbers were coming down nicely. I slotted the holes drasticly on another TPS that I had and now my closed voltage is .37 or .39, and my WOT is 4.89v. If I slot the holes any more I will break through the sides to achieve thos numbers. For sure to get to 4.6v I will have to break through the sides.

I had to stop for the night so I swapped the unslotted one back on to drive to the tune. Taking my slotted one with me in case. I also stopped because as you mentioned above, the computer may be seeing a totally different voltage than what my volt meter shows. I thought it best to wait and see what it shows at the tune.

I read in another thread here posted today, Russ K mentioned that with HP Tuners, you can raise the max voltage reading way past what the stock pcm is set to before it throws a code. Is this what others are talking about when they are saying to just datalog it? Slotting the holes I see will work, but you got me second guessing what numbers I am seeing on my meter I will see what tomorrow brings. It will be nice to hopefully have my car running 100% for once.

thank you all for being patient with me.

mark jr.