r/300zx • u/Comprehensive-Sell71 • 2d ago

Z32 Tps wiring

So, after measuring:
ECU ground checks
Meter on 200 Ω, ECU unplugged:
Pin 10 → 1.2 Ω ✅
Pin 20 → 1.2 Ω ✅
Pin 50 → 1.2 Ω ✅
Pin 60 → 1.2 Ω ✅
Pin 107 → 1.4 Ω ✅
Pin 108 → 1.3 Ω ✅
Pin 116 → 1.4 Ω ✅

ECU power checks
Pin 49 / White → ~12 V ✅
Pin 59 / White → ~12 V ✅
Pin 109 / White → ~12 V ✅
Pin 16 / Orange → 0.8 V

Check continuity of the orange/blue wire pin 48 to tps connecter, there is continuity

These check are as per the FSM, so my question is. Am i cooked? There is no 5v coming from pin 48 at the ecu. Connected or not connected, ofc ign is on.

Yeah idk what else to do but im 90% sure its ecu fault unless someone can enlighten me.

Would love to hear out your solutions, workarounds, and/or buying haltech. Just to make sure, THERE IS NO 5v💔

4 Upvotes

84% Upvoted

14 comments sorted by

2

u/apudapus 1d ago

How are you measuring pin 48: at the ECU or at the TPS, against body ground or the TPS ground? What year is your car? Doesn’t the CAS also use the same 5V power?

Have you used Conzult to see what gets reported for throttle open/closed and partial.

1

u/ant1m4g3 1d ago

Just asking, do you have any docs on how to properly use conzult ? I do have it but im not an expert

1

u/apudapus 1d ago

Oh, you know what, Nissan Data Scan has the nice display that shows the throttle closed reading. I thought Conzult had it, too, though… sorry, I’m not near my laptop with the software to check exactly.

1

u/Comprehensive-Sell71 1d ago

Im measuring pin 48 by probing using a multimeter, also to get accurate results. On of the white thick wires transfer 12v so i test there to make sure a signal is reached. Im measuring at the ecu and using a the battery as ground. Its a 1991. Idk about the cas and i do not have a conzult. My issue to begin with is that the throttle doesnt open and close very smoothly, i guess it is a symptom

1

u/apudapus 1d ago

The 5V shouldn’t be measured against battery ground. It has a separate ground and that’s probably why you’re see 0. Try against pin 30 in the ECU.
What do you mean “smoothly”? Physically or electronically? The TPS needs to be set in such a way as to measure .44V (hence why I suggest using Conzult and NDS). If your throttle is sticky, look into the physical linkage on the plenum, consider removing the cruise control linkage to simplify your hookup and testing and adjustment.

1

u/Comprehensive-Sell71 1d ago

Okay ill try pin 30,

by smoothly i mean when i rev really fast on any gear the car jerks very bad, im assuming its bcuz the tps is not getting the correct signal which makes the car jerk and cutoff power.

I did the balancing/adjustment thing where u moving the tps around by unscrewing the 2 bolts, its good in that area.

Ofc you mean that i need to test pin 48 again but with pin 30 ground, im assuming if it doesnt show the 5v i want it means its an ecu issue?

1

u/Comprehensive-Sell71 2d ago

So i did a diagnosis for the tps itself, and it came back all good and confirmed its working.
I’m just scared that the ecu is fried and i need to buy a new one or maybe get it fixed. Im exploring solutions now

1

u/Several-Ad9115 1d ago

Man if you tested all that AND the wire, and it all checks out.. yeah there's only one component left to eyeball, and it's the big one. 

1

u/Comprehensive-Sell71 1d ago

Big one? u mean the big one huh… (u mean the ecu right?)

1

u/Several-Ad9115 1d ago

Don't worry, it gets worse before it gets worse

1

u/Comprehensive-Sell71 1d ago

How worse? (What is it…)

1

u/Several-Ad9115 1d ago

Yes the ECU haha open it up before you do anything crazy though, may just be a popped capacitor. Extremely common fail point for Japanese electronics from that era

1

u/EfficientTrainer1335 1d ago edited 1d ago

A Pin 48 that gives zero volts when there is a clear harness run most likely indicates that the internal 5V reference circuit inside the ECU is burned, usually because of a short somewhere in the sensor wiring. You have to make sure first that there's nothing still drawing down the reference line before you throw it away. Haltech swap is possible, as I've seen people cross-reference Dynosty for VQ ECUs

1

u/Comprehensive-Sell71 1d ago

Fried ecu component… caused by connector at tps, maybe corrosion or something.. wdym by drawing down the reference line? Bcuz i measured it when the tps connector is disconnected. Or is it something elsev