Electronics help with TPS circuit.

[MR 1JZ]

yeah funny that...

[brett_celicacoupe]

reviving this one with some relevant info (hopefully).

i have a ex aristo 2JZGTE in the soarer.... until today i didnt have the NSW circuit for the auto connected properly. while it wasnt connected i never noted any 'fake rev limit' at WOT. there was also a side effect of not having it connected which made it stall going into gear. OD light was also flashing

anyway when i did setup the NSW properly, (had to ground black, yellow trace wire) i took it for a run down the road. pulled out of the driveway and gave it WOT, and then it hit the limiter thing

im yet to determine if there is a power difference between having it connected and not. i havent been driving the car with this setup for long.


does the ecu expect 0V or 12V for the kickdown switch? i think it will be easiest to make a voltage switching circuit off the TPS

[cambelt]

Pretty sure kickdown switches to ground . Didnt you just use the loom as it connects to the g/box. one side of the NSW connects back to the ecu anyway, it grounds itself thru the start relay coil.
Dave

[brett_celicacoupe]

ive done my NSW differently but i just took it for another drive, back-to-back having the NSW wire grounded, and then disconnected.

it definately goes as hard with either configuration.

not having it connected though eliminates the rev limit at WOT. i basically had it flat to the floor from 20k and it changed at 6200rpm in 1st and second.

then, ground that wire and it hit the limiter doing the same thing

[Mos]

Hmm that's *very* interesting!!
(nothing else to say at this point )
Mos.

[brett_celicacoupe]

someone should test this on their car.

it also does weird things when its not connected. the ecu breifly cuts the engine when changing from N to D/R or R/D to N :S

[Mos]

it also does weird things when its not connected. the ecu breifly cuts the engine when changing from N to D/R or R/D to N :S

Yeah, that effect is well known and documented - NSW and STA basically tell the ECU when it's in neutral, so it does appropriate things to idle during transitions.
Mos.

[wilbo666]

I had a quick look at the ECU diagrams...

NSW :
0- 3 volts with the ignition SW on and the shift lever P or N position
9- 14 volts with the ignition SW on and the shift lever except P or N position

The ECU diagram I have shows a diode from the ECU ---|>|---NSW, so it looks to be active low...

Btw does anyone have a JDM 2jz-gte wiring diagram? All these yank ones with AFMS and what not are annoying me

Cheers
Wilbo

[cambelt]

I dont think anyone has the true aristo JZS 147 diagams. There sure would be a few of us that want them including myself.
Dave

[wilbo666]

I dont think anyone has the true aristo JZS 147 diagams. There sure would be a few of us that want them including myself.
Dave

Gay gay gay....surely they must be around somewhere!

Cheers
Wilbo

[brett_celicacoupe]

Yeah, that effect is well known and documented - NSW and STA basically tell the ECU when it's in neutral, so it does appropriate things to idle during transitions.
Mos.

im still curious as to how the ECU knew when i was changing gears. for a while there when i didnt have everything connected, it was still cutting the engine when i went from R/D>N. i didnt have the NSW wire grounded, nor did i have +12v at the selector switch common

[Mos]

im still curious as to how the ECU knew when i was changing gears. for a while there when i didnt have everything connected, it was still cutting the engine when i went from R/D>N. i didnt have the NSW wire grounded, nor did i have +12v at the selector switch common

There is a pullup to 12V inside the ECU, with the other side being pulled down to ground by the starter relay coil - by checking states at the NSW and STA pins the ECU can determine the state of the neutral switch, even when cranking.

I imagine the auto presents varying loads to the engine depending on the gear it is in, with the ECU trying to account for that on transitions - hence the stalling when moving it out of N... chances are it's a bit more complicated than that but I haven't really investigated it much.

Mos.

[cambelt]

When i was testing my one i didnt have the relay coil grounded and yes it would stall when i shifted from any gear into N OR P
Dave

[brett_celicacoupe]

When i was testing my one i didnt have the relay coil grounded and yes it would stall when i shifted from any gear into N OR P
Dave

did you drive it like that?

[Mos]

I drove it like that out of my driveway, realised it does it, scratched my head a bit, stuck my tongue out just the right way, hooked up some little jumper leads to the coil of the relay and continued on my merry way until I had time to fix it properly
Mos.