TPS: Min 12.5%, MAX 82.5%

[beatshack]

Hi, I recently got my pocketlogger setup, and I've been learing a lot of whats going on with my car.. very helpful tool, I can't imagine not having it now..

My question: my TPS reading sits at 12.5% when off throttle, which I think is fine, but my max throttle, pedal to the metal is only 82.5%.. I have physically checked to see if the plate is opening 90 degrees (friend floored throttle while i looked), and it is.

Is this normal?

 

[DSM90AWD]

My question: my TPS reading sits at 12.5% when off throttle, which I think is fine, but my max throttle, pedal to the metal is only 82.5%.. I have physically checked to see if the plate is opening 90 degrees (friend floored throttle while i looked), and it is.

Is this normal?

With the throttle cables properly adjusted (and not binding) your TPS should read 10% (.51V) at idle and 100% (5V) at WOT. It is possible your TPS sensor is either faulty or needs to be readjusted.

Per my Haynes, on a 1990 TPS the resistance btw terminals 2 and 4 of the TPS plug should range from 1,100-5,600 ohms (throttleplate closed - fully open). Resistance btw terminal 2 and 3 with throttleplate closed should be btw 3.5K and 6.5K ohms.

If either of these are not correct, it is likely the TPS is bad and should see a CEL code=14.

If the TPS checks out ok then it is likely it just needs to be adjusted. Simply datalog the TPS%, lossen the two TPS Snesor mounting screws and adjust (rotate) the TPS sensor so it reads 10% (.51V) with the throttleplate closed

 

[beatshack]

i have a feeling the TPS is bad.. after more careful logging, i have noticed the TPS randomly flickers between 82.5% and 87.5% at WOT... good thing i have a whack of spare TPS's from hyundai's

i probably won't see a CEL code until the TPS is absolutely fried.. i've had another go bad on my 94 ES, and it was so bad the car would buck on slight throttle (voltage spikes) but still had no CEL code.

btw thanks for the detailed reply

P.S. how did you manage a low 12 with 289 whp?

 

[DSM90AWD]

P.S. how did you manage a low 12 with 289 whp?

sandbagging on the dyno

 

[boostyGST]

does anyone have the specs that a 2G TPS should be @ % wise @ close throttle and full open throttle?

Thks

 

[oldman]

sandbagging on the dyno

More like installation of the best flowing 1G o2 housing after the dyno.

 

[Stapl3]

does anyone have the specs that a 2G TPS should be @ % wise @ close throttle and full open throttle?

Thks

My 2g was 1-2 at idle and 100 at WOT. I was never too concerned with the idle, rather the WOT. It's WOT where shit happens.

 

[steve]

2G's seem to scale (report the lowest voltage seen as 0 and the highest as 100) the output of the TPS that is sent to the datalogger, or the datalogger software is doing it. Doesn't matter too much since the only thing your adjusting a 2G TPS for is the point where the internal IPS is opening. The actual voltage output from the TPS on a 2G at idle is quite large.

On a 1G you adjust the TPS for about 0.5v at idle (0.48 to 0.52v) What the TPS reads at WOT is largely unimportant.

With both generations, as long as the physical butterfly opens all the way, then whatever the TPS reads is what it reads. The ECU is usually looking at the change in voltage from the driver moving the pedal and not some magical voltage.

This all assumes a good TPS. If your TPS drops out or spikes in voltage as the throttle moves it's bad.


Steve

 

[Kevin Jewer]

For the most part the ECU only cares about relative movement of the throttle, not absolute position. But there are a couple things that still depend on TPS. 2Gs use the TPS for the closed throttle switch as well, which the ECU needs to see closed before it will go into closed loop idle speed control (this applies to 1Gs as well, but they use a seperate switch). You need to be sure that input is switching. On every car I have worked on that happens around 1%, so it makes sense to set the TPS so that it is just barely on zero with the throttle closed. Anything over about 90% the ECU will consider WOT, and most cars end up over 90% with the zero point set properly.

The 1g ECU may not care where TPS is at idle since it will still get the throttle closed signal from the switch. If the ECU goes into closed loop idle speed control it is probably fine. But it still makes sense to be close to zero. WOT should be fine as long as the throttle plate gets the full range of motion (cable tension set properly).

Since cable setup is important to getting the TPS set up properly, we might as well mention something about that. The easiest and best way I have found is to loosen the bolts holding the bracket, have a friend floor the throttle pedal, pull on the cable until the throttle plate is opened hard against the stop, then tighten the bolts. This will assure full opening range and maximum slack at idle to prevent idle issues when the cable warms up and expands.

 

[beatshack]

Thanks for the informative posts guys. Greatly appreciated