Tps Calibration/relearn

[jase_c]

Hey guys,

i have just fitted a Plazmaman plenum and 700 cold side piping kit on my 34Gtt and have the hunting/high idle problem. I have just reset my TPS to .44 volts as it set to .12 when i first installed the tps in the throttle body, but now the ECU thinks the throttle is open slightly.

Can someone tell me how to calibrate it to tell the ecu that where it is set now is throttle closed?

[89CAL]

What ECU?

[jase_c]

stock ecu Nistuned

[89CAL]

I'm not sure how you do a reset on those? The stock ECU can be done by unplugging the battery and turning on some electrics to drain any residual power, then leave it for a while then hook the battery up and it will figure everything out again.

Can't say this will work with the Nistune, or if you will lose your tune etc. I don't know enough about them. But here is a link to the Nistune manual that might have some answers : Nistune Manual

[jase_c]

Yeh Nistune manual has nothing really, its whatever the process is for the standard 34Gtt i am pretty sure. I have the battery disconnected at the moment so will see if that works tommorow, have also read somewhere that you can go WOT then turn the ignition on for 10 seconds then ignition off? whether thats a myth or some of that process i am not sure but hopeing someone will have the answer.

Edited September 22, 2014 by jase_c

[GTSBoy]

There's no such thing as "idle position learn" on Nissan ECUs. 0.4 - 0.5 volts is it, with an ideal in the 0.45v range.

[jase_c]

So i have to drop it back to .12 volts to get the idle circuit active again? There must be a way to tell the ecu thst the new voltage is 0% throttle surely?

Edited September 22, 2014 by jase_c

[GTSBoy]

There must be a way to tell the ecu thst the new voltage is 0% throttle surely?

Why must there be a way? It is an OEM ECU that was never intended to do anything other than work with one type of TPS on one type of throttle. The ECU knows that idle is at 0.45V and you physically adjust the TPS until you get that voltage when the throttle is closed. That's the end of it.

The fact that something is wrong with your ECU's understanding of what voltage is "throttle closed" is another matter entirely. It doesn't make sense.

[jase_c]

I guess the question is then why wont it register idle at.44 volts with an oem tps, or why has it changed from unbolting off the stock throttle body and onto the new one when all thst happened was the connectors were unplugged? I just assumed there would be a way to calibrate the system.

[Ben C34]

Are you sure that's the problem? How have you concluded the ecu isn't registering the tps is shut and that it's not a vacuum leak?

Do you have a consult cable and either nistune or other software to see of the idle flag is being raised?

Nevertheless, I would be thoroughly checking for leaks, which is something that should be done any time you mess with anything intake related.

Edited September 22, 2014 by Ben C34

[jase_c]

Yes i have consult cable and nistune software which is why i can see the tps idle light go out as i turn the tps to get to .44 volts.

[Ben C34]

Yes i have consult cable and nistune software which is why i can see the tps idle light go out as i turn the tps to get to .44 volts.

So set it to .4

[Ben C34]

Did you change the throttle body I the process?

If you did, it could be allowing more air at idle, so you will have to sort that out also to get it to idle nicely.

[jase_c]

It will o ly register tps idle at .12 volts which is nowhere near .4 volts.

Its a plazmaman throttle body but the throttle is fully closed so it shouldnt make a difference what size it is.

[Ben C34]

It will o ly register tps idle at .12 volts which is nowhere near .4 volts.

Its a plazmaman throttle body but the throttle is fully closed so it shouldnt make a difference what size it is.

Fair enough.

So just to clarify I seriously doubt anything is wrong with the ecu or tps. The main thing you have changed that will upset the ecu Is the throttle body.

Maybe the ecu sees alot of air running through the engine even though the tps is at .4 volts and doesnt believe the car is at idle. Can't you look at the idle control valve duty cycle? I bet it's really low, or off all together.

I'm betting it's the throttle, assuming you have no leaks, but if you choose to ignore that it's cool with me.

Email matt at nistune and ask him what conditions have to be met for the idle flag to be raised. We know that the voltage is one, maybe there are more.

[jase_c]

Ok, so i had the battery disconnected overnight, put the terminals back on this arvy and turned ignition on then put the accelerator flat to the floor for 10 seconds then released and turned off and now the TPS idle has reset and is accepting .44 volts as closed throttle. Started the car and still have high revs so i clamped the IAC hose shut that goes to the piping before the throttle body and the rpm came right down so i am thinking that the IAC is stuck open?

Even then the rpm is still a little high so there must be a vacuum leak somewhere i guess, but at least i am making progress, thanks for the input 89cal, GTS and Ben.

[Ben C34]

Air will always rum through that pipe as that's where the idle adjust screw is. So the throttle should be 100 percent shut and the air bypasses through there even when the Iac valve is shut.

Really sounds like the throttle isn't shut enough for the ecu to be happy.

Is is adjustable at all?

I would adjust the idle screw to see if you can drop the idle enough, but really before doing anything I would be pressure testing for leaks. Then look into making the throttle close more, maybe by filing the stop down or something if it's not adjustable.

Glad some progress is being made.

[jase_c]

yes the throttle is adjustable, i have backed it right off but may have a quick look inside it to make sure it is properly shut. i clamped the pipe to check the IAC operation as i was a little suspect on it, so i know there is a problem there so will be taking it off to check it all.

[Ben C34]

yes the throttle is adjustable, i have backed it right off but may have a quick look inside it to make sure it is properly shut. i clamped the pipe to check the IAC operation as i was a little suspect on it, so i know there is a problem there so will be taking it off to check it all.

No, there's not necessarily a problem with the iac as the screw will always bleed air, even if the solenoid is unplugged. You could unplug the solenoid but I don't expect anything to change when doing that.

[jase_c]

Yes but theres a problem if it doesnt decrease the rpm as the engine warms up, the car revs at over 2000rpm until i clamp the pipe