Please tell me there is a way to.....

[TXCAMSS]

Well no luck with the reset or the MAP tuning changes. It looks like it is going to be voltage related.

If there was just a way to raise the tps trigger for WOT FTC 22 from 2% to 4-5% I'd be good to go. Man talk about frustrating. It just idles so well in FTC 20.

[flame]

I'm just trying to wrap my head around this so if I'm out in left field just say so. It isn't possible for the TPS % to raise on its own. You have double checked the throttle plate stays closed so that only leaves a voltage increase which leads to the % increase causing the FTC change right? Could be a voltage regulator issue bring battery voltage and 5V ref higher which leads to increased TPS voltage. Check battery voltage and 5V ref KOEO then KOER and then when the % increase happens. IIRC anything above .35 is good for closed throttle TPS volts so maybe lower it as far as possible.

[Sam88gta1]

Well no luck with the reset or the MAP tuning changes. It looks like it is going to be voltage related.

If there was just a way to raise the tps trigger for WOT FTC 22 from 2% to 4-5% I'd be good to go. Man talk about frustrating. It just idles so well in FTC 20.

What throttle body do you have on the car?
If you were in Dallas I could fix this for you.

[TXCAMSS]

You lost me on the KOEO and KOER. I have a few FBodys so I may try a Altenator swap for S&Gs. Yeah I am going to try to disconnect the Racetronics hotwire kit/harness and plug the stock harness back in to see if the voltage issue misteriously goes a way. I had a friend tell me about a another guy that had this problema nd it was resolved when he swapped to a new fuel system harness. I'm also going to try to disconnect the alternator or pull the belt temporarily to eliminate any additional voltage, just as a test.

I have the Nick Williams 90mm TB. It would worth the drive at this point.lol. Is there anything I could do on my end? I thought about installing diodes on the TPS wires, but not sure if that would help control the voltage.

[flame]

Sorry it means KOEO key on engine off and KOER key on engine running

[LSxpwrdZ]

I had a similar issue on my 98 TA. After it ran for a little while it would idle high and never go into idle routine so I logged it multiple times and found that the TPS% would increase over time and the voltage would rise with it. Mine ended up being a TPS sensor failure so I replaced it and fixed my issue.

This is another scenario, the TPS% is just a lookup of the voltage. The lower bounds are the lowest recorded voltage data to equal 0%. Example... lets say you've set the throttle body up to where closed throttle is .55v and you drive it around and the voltage suddenly fluctuates when the throttle is closed causing a voltage dip to say .41v. Now that the PCM has saw a lower voltage it automatically assumes that 0% tps is now the lowest voltage of .41v when in reality it's still .55v. So now when the throttle is actually closed and reading .55v the PCM looks up and reports 2-3% instead of 0%.

I'm not totally sure this particular example is what mine did but seems like it's what yours could be doing.

[Montecarlodrag]

I had a similar issue on my 98 TA. After it ran for a little while it would idle high and never go into idle routine so I logged it multiple times and found that the TPS% would increase over time and the voltage would rise with it. Mine ended up being a TPS sensor failure so I replaced it and fixed my issue.

This was exactly my problem and solution.
TPS raised from 0% to 2% or 4% with no reason, idle climbed to 2500 RPM. A TPS reset fixed it but the problem returned after a few minutes at idle.
New TPS sensor solved it.

[JANNETTYRACING]

This is Just an Idea, Battery voltage starting out low and rising as the car runs, ( due to a crappy battery or weak alternator) the TPS is a Variable resistor and output voltage is in direct relation to input voltage even though the input voltage should only be 5 v maybe it is starting low and creeping up?

Did you check and watch the TPS input voltage?

Could also be Ground Related, high resistance at ground points or cables.?

Ted.

[Frost]

The 5VDC sensor voltage is regulated; it's not going to be moving around with system voltage.

[JANNETTYRACING]

The 5VDC sensor voltage is regulated; it's not going to be moving around with system voltage.

I don't suppose Regulators ever go out of spec either then, it won't hurt to check that is all I am saying.

Ted.

[TwoFast4Lv]

We have been chasing this problem for many years on verious cars. Odd no one had ever heard of it till now seeing we have posted threads on it.

To date no real fix. We have changed compters, sensors, alternators, batterys, cables, engines, transmissions, Throttle body's and most any thing else you can think of.

I would love to find a fix and not be told it can't be happening over and over again

[mowton]

Not sure if this fits, but we had this issue on an EFI conversion (2000 Vette PCM) project and the problem was a bad common ground for the Coil Packs.

I'll look for my notes tonight, but some how it raised the TPS% due to noise if I remember correctly and threw everything off. Car ran like crap at times as well though.....

Ed M

[Google]

See this thread is old.. But.. If you change your Map & Rpm Boundaries you can control what Cell the pcm goes into.

I also had a TPS voltage issue.. Under WOT the tps would go to 100% then slowly drop off to 73%.. Took alot to figure it out as battery volts was fine when logging. Battery failed a few months later and after it was replaced TPS stopped falling. Assuming that the coils, fuel pump, and injectors were to much of a draw on the bad battery to keep up or it could have been feedback from a bad cell.




.

[Google]

Can also play here..




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[Frost]

Can also play here..




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Those fields are present in all OS's but don't seem to be functional in all. In the past, I spent time there as well as other places trying to alter the min TPS for idle and got nowhere. Those fields define airflow modes and will still not allow adaptive idle to update (as they do not pertain to the same). In logging, if the TPS flickers or moves to 0.8% or >, that's where the issues come in. If you can keep it to 0.0 or 0.4%, you will be free and clear. The flicker to 0.8% will keep the car from idling and returning to idle.

[Google]

Those fields are present in all OS's but don't seem to be functional in all. In the past, I spent time there as well as other places trying to alter the min TPS for idle and got nowhere. Those fields define airflow modes and will still not allow adaptive idle to update (as they do not pertain to the same). In logging, if the TPS flickers or moves to 0.8% or >, that's where the issues come in. If you can keep it to 0.0 or 0.4%, you will be free and clear. The flicker to 0.8% will keep the car from idling and returning to idle.

True, but for the op's os it works.



.

[Frost]

The bigger issue would be this though, which is true for all of the OS's: They define the shift time from Dyn to steady state at idle for airflow calcs; you still need the idle adaptive to run.

Those fields define airflow modes and will still not allow adaptive idle to update [operate] (as they do not pertain to the same function).

[camaro]

i am having same issue with the tps flickering %, have tried all adjustement and resets,another tps but always comes back to 0.4-0.8

[Google]

tps volts should be 0.55v - 0.60v normal range.




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[Frost]

i am having same issue with the tps flickering %, have tried all adjustement and resets,another tps but always comes back to 0.4-0.8

I am working with a customer over email right now who's TPS reads 0.0% with engine off and it goes right to 0.4-0.8% as soon as the engine starts... On his car, it's not even a TPS voltage issue because the data logger shows the same issue EVEN WITH THE TPS UNPLUGGED!!

Best Seinfeld voice: What's that about?