How To Learn Tps In Stock Ecu

[alekseymenkov]

Hey guys,

I have a problem with my skyline R34 rb25det neo MT

I adjust TPS sensor to 0.5V (like in manual), but in consalt, flag "Closed TPS" is OFF.

How to learn TPS?

I hear, there is a way of 5 times turn a key to IGN, and back to OFF position.

[Duncan]

I'm not certain for R34, but on R32 there is a separate throttle closed switch, it doesn't use the TPS output. in any case the stock ECU wouldn't be adjustable.

Have you tested at what voltage/adjustment the throttle switch closes?

BTW what are you trying to fix?

[alekseymenkov]

I find a way to adjust the TPS!

First, you need to calibrate base idle to 600 rpm.

Next, you need to adjust the ignition timing to 15 degrees.

At last, rotate TPS to 0.5V, like an manual, and do following:

Key to IGN -> wait 5 sec -> Key to OFF -> wait 5 sec -> Key to IGN -> wait 5 sec -> Key to OFF -> wait 5 sec -> key to IGN -> check "TPS closed" flag in Consult. It will be ON!

You need to do 5 turn of key, or more with 5 seconds waiting.

Duncan, I want to calibrate all sensors to stock values (like in manual)

Before, my TPS closed at 0.42V.

Edited April 24, 2016 by alekseymenkov

[ob1]

i know this is a thread revival, but i (think) i have the same issue i.e. i cant get my ecu to understand the correct voltage to turn on the "throttle closed" flag, which is causing very high idle.  Can anyone else comment on how this learning procedure is supposed to work?  Turning the ignition on and off 5 times did nothing for me.  Consult is reporting that the throttle closed flag is only coming on at around 0.2v, which is too low to be in spec.

[ob1]

well i fixed it.  The 5 x on/off trick is what is necessary on a GTT to reset the ECU's threshold for "closed" throttle TPS voltage, HOWEVER, you must also meet the pre-requisite sensor conditions before starting.  For me, i had to wiggle my gear lever a little until the Neutral Indicator came on solid in NisDataScan, then the 5 x on/off worked.  My neutral switch must be on the way out.

I have also read (but cant confirm) you have to:

- be stationary (der!).

- have the coolant temp above a certain temp.

- have the battery voltage above a certain level.

[nicostar]

can anyone confirms if this works for rb20det?

[GTSBoy]

Does not work for RB20DET and is not necessary.

The RB20DET does not use the TPS potentiometer to determine closed throttle position. There is a switch. You can manually adjust the TPS position so that the switch actuates at the slightest opening of the throttle. Do that and you are gold. If you lean over the engine and open the throttle, you will hear the injectors double pulse. That's the ECU's response to seeing the TPS come off the switch. You want to hear that at the tiniest movement. Tiny.

[joshuaho96]

Major thread bump, for the RB26 (and likely the RB25 I'm guessing) the idle switch is a mysterious thing that somehow resets if you unplug the 5V supply (not the connector with the EV1 style metal clip) while the ECU is on. No need to do weird key tricks, no need to run the engine at all. Just turn the key on to get the ECU running, adjust the TPS to get the requisite 0.45V at idle, tighten it down, then unplug the TPS and plug it back in. It seems an awful lot like the ECU is using TPS voltage for idle detection but if you look at the R33 FSM it details how there's a physical switch in the TPS and that directly goes to the ECU for idle detection. I have no idea how that works.

[Duncan]

Yeah, I'm not sure why, but the stock ECU does use both a throttle switch and the TPS. Aftermarket ECUs just use the TPS so the switch is no longer required.

[joshuaho96]

On 2/4/2022 at 2:07 PM, Duncan said:

Yeah, I'm not sure why, but the stock ECU does use both a throttle switch and the TPS. Aftermarket ECUs just use the TPS so the switch is no longer required.

It was pretty curious, I noticed that the ECU basically doesn't do closed loop idle control if it doesn't see the idle switch. So it can idle low or high depending on coolant temp. I suspect it's also to help transient fueling control as well, it can be pretty hard to tune throttle tip-in just off idle.