Tps %

[waynehartwig]

Curious... 08 Sierra 5.3. Throttle is not restricted, but according to the software, my throttle is from 23% at rest to 80% at full throttle.

When tuning, do I tun in the 80% area instead of 100% when I'm looking at WOT? Or is still 100%, even though the peddle at WOT is only 80%?


Reason I ask is because my rig won't down shift and by the time I get across the intersection, it's already in 4th gear. Causing it to lug and vibrate until I get some speed up/manually gear down. Course I can guess and start changing things, but I figured I'd ask first

[talsayed]

my throttle is from 23% at rest to 80% at full throttle

Log ETC position % pid instead of Throttle position sensor & you'll be able to see (100%) WOT

[waynehartwig]

Log ETC position % pid instead of Throttle position sensor & you'll be able to see (100%) WOT

I don't mind seeing 'part' throttle, I'm more concerned with tuning at this point.
...So do I still tune based on the 100% then? IE if I want something to happen at WOT, do I cahnge the 100% or the 80% numbers?

[Mep_q8]

I normally set my PE enable tables to 87%.. just to make sure that whenever I'm at WOT it will kick in at 87% no matter what... logging TPS% will show you 87% at WOT and logging ETC Position will show you 100% at wot, so either way your a winner

[waynehartwig]

Cool! Thanks guys!!!

[Geo]

Excellent, this answered my question as well.

[ericwilloughby]

05 A4 GTO here. I was looking into the 88% issue because my ecm ignores rpm shift points and shifts at mph. I.e. I set wot shifts to 5000 and raised mph shifts 10 mph over stock and it won't shift until 7000 rpm. Why? Not because tps says 88% but the table is looking for 100%?

[Braemerz28]

So that explains the top end, why won't my ETC ever read 0%? Or are the throttle by wire TB's using the throttle blade for IAC instead of a separate valve?

Thanks!

[ericwilloughby]

This question was never answered. Most of the tables say "TPS" ,I.E. shift points, some do not say at all. What do the % tables look at? TPS or ETC?

[ericwilloughby]

If that is true then is should read 100 at WOT instead of 88% shouldn't it. Regardless of all that, the scanner should be reading which ever PID the HPT software is referring to in its adjustment charts. Which PID should we be looking at to base our tuning decisions on.

[BBA]

The actual TPS% will never be zero, that's because the LS series use throttle for idle instead of the older style that used an IAC to bypass throttle. As for WOT, 100% would be 5v on the TPS, which it will never reach. The PCM does have a max TPS limit built in, on vortec trucks the limit is 83%, on cars it's 87%, they use different throttle bodies with airflow ramps that flow best at the opening GM limited it to, so that explains it.

If you wanted to get the full open on a truck you would have to use a car PCM (somehow making it work with the rest of the trucks modules) while removing the ramps in the throttle body and removing the hump in the intake opening behind the throttle body ramps (or a spacer plate would help).

BTW: it's the hardcoded secondary PCM code that limits it, nothing HPT can currently access or change.