Nistune Forums

Hi, I'm new here, but I've been reading through. I don't have a Z31, but I'm running the 86 ECU, Titania O2 sensor, and MAF in my 1983 280ZX Turbo. I recently set it up with Nistune, it's been running good. I can connect up to consult sync to PC and ECU. Haven't tried burning permanently to the ROM yet, but everything seems to work. Have done logs etc. Was adjusting my idle A/Fs as I was sitting there and noticing the difference. Anyway a few small things I've noticed.

1.) When I had the 86 ECU running without Nistune I had no problems with the O2 sensor. Light would flash more than 5 times at 2000 RPM over 10 second period as FSM describes. I've noticed that with Nistune in the Consult gauges it won't register any voltage for my O2(LHS) sensor it'll just sit at 0.00. I even tried unplugging the O2 sensor and shortly the DTC code for O2 sensor popped up. I'll have to try this again, but that'd indicated I'd think that the O2 sensor is working. I don't know if it's because it's the Titania? Oh I tested my O2 voltage with a multimeter and it was bouncing around from .3-ish to 1.3 when holding the RPMs up.

2.) A few things seem to be slightly off. Battery Voltage and RPM seem to vary a little by this I mean the RPM readout on Nistune Consult is a little lower than what my Tach shows. Also my battery voltage reading on consult will be lower as well. For example I was getting 13.9v on the consult readout, but when testing the voltage at the battery with a multimeter I'd be getting a 14.2v reading. Has anyone encountered these issues?

3.) Finally DTC codes. I keep getting a persisting Ignition, and Fuel Pump code from the Consult DTC. I clear it but the next time it'll be back. Car runs fine with no problems. I don't know if this just happens to do with the slightly different wiring between the 280ZX and 300ZX.

I wonder if any of this could be related to the ECU? I'm not really sure, but I figured maybe you guys could provide some advice. I've asked Matt about the O2 and voltage things. At one point the USB board had come in contact with the ECU. I pulled everything back out, put the factory ROM back in and it was still ok. So I put the Nistune board back in and resoldered the wires to the processor and haven't seem to have any problems. I just figured I'd ask any of you guys with Z31s for help. If it comes to it, I have another 86' ECU that's been socketed so all I'd have to do would be to pop the Nistune board in and solder the 4-wires.

I've emailed you back. Responses below

1. I'll retest the O2 voltage sometime over the weekend when I get a free moment and let you know

2. There would be some voltage drop through the wiring to the ECU so that is to be expected from the battery

3. Fuel pump expects a certain feedback resistance and if out of range raises this code. Wouldnt worry about that too much. Ignition signal occurs when feedback from the power transistor indicates a problem (can be caused by miss in ignition etc)

I may have to go through my ignition wiring. Yet the car seems to run fine, although every once in a while I will notice a miss, It seems like I have a miss somewhere in the system I've never been able to track down. I've replaced the cap, rotors, plugs, wires, ignition module(power transistor).

I'm not too worried as I really haven't had running issues, it only seems to be at idle. Maybe a small intake leak or something.

I was curious if you had a chance to mess with the O2 sensor testing?

Oh another thing I noticed. I don't know if this will make any difference or not. I was reading the topic about AFR cycling and people talking about setting bit 3 or not. Anyway I noticed everything in Feedback Flags was checked except for Bit 0 and Bit 2. Would this cause it to ignore the O2 sensor or no?

My car misses as well.

VERY VERY little.
its CERTAINLY not a miss from the engine.


Its a miss that occurs every 3-6 minutes, (randomly) and it will just hic-cup, but it is SOOO MINOR of a problem I will NOT and am not going to try to track it down.
Its the same miss as your describing.

Alright I'll give this a quick update hopefully someone can give me a few quick thoughts on this.

1.) When playing back my log file sometimes I'm having issues and it's giving me a UpdateLogGraph: Internal Error - can't display log for register 0x2E.
Edit: I think this was because I was accidentally trying to log a value on the graph that was from my wideband O2. I don't currently have my Wideband O2 hooked up. Once I changed the graphing parameters to the default ECU reportings this error went away.

2.) I'm still curious about the O2 issue. I saw someone else with an 87' 300ZXT was using NIStune and it gives them a read out in the consult gauge display. Mine still will give no remote readout for the O2(LHS) gauge. I don't know if I just have a problem with my NIStune board, ECU, or what. I see bit 3 is checked which I know was mentioned controls O2 feedback so I don't know if having that checked would cause NIStune to not use my O2 sensor? Could that be an issue?

3.) As far as my car goes I've noticed that when just at a stop in the consult display the code for the Throttle Position Sensor will either slowly or rapidly show up then disappear. Even the TP gauge in the Consult will display a varying value around 15-16 and keep switching between the two. I would think this value should technically not be switching?

Sorry still got the O2 sensor issue on top of my to investigate list. I'll have a look into it this weekend with my car since same ECU

It's alright, it's not a huge deal. It's just that I wanted to see if I could find out just to know if something was wrong with my nistune install or something. Although I don't suspect there's anything wrong as everything works. Connects, doesn't randomly disconnect. It'll sync up fine, seems to log everything, and I've successfully burned different maps to the ECU a few times.

I am running the 87t ecu also. At this time i am not getting a readout for the o2 sensor either. At one point i was as can be seen in one of my previous posts. I am not sure what version i was running when i was getting a reading. I recently installed version 9273 and noticed it wasnt working. Then i decided to reinstall version 9266a which is the version i thought i was using when i got the o2 readout, but it did not solve the problem. I have yet to check that my o2 sensor is working, it is on the "to do" list. Nistune is also showing that the a/c switch is on even though the a/c is off.

Thanks,
Brian

Oh and by the way, I received the ecu's back Matt and everything seems to be working again besides the o2 readout issue.

Ok, well then its actually good to know that I'm not the only one with this issue. It was just more or less like I said, when I noticed it wasn't giving any sort of reading for it I began to wonder if maybe I had done something wrong with installing Nistune and what not. It was my first time desoldering and soldering, but I did make sure to practice alot before I took the plunge and installed.

Hey magic formula, you mentioned that you wouldn't get a readout for the O2 sensor. Has this changed for you with the latest versions of nistune or are you still unable to get the O2 readout?

if you guys want to try the 'Consult RAM trace' option inside Nistune, enter in Addr=0000 and Size = FF

Next monitor row =0, column = 5

This maps upto memory address 0005. It will display the current O2 voltage in hex (also can show decimal). Please let me know if it is showing anything other than 0

hi matt, i also have the zero volt o2 sensor problem.

did the ram trace and that address is indeed staying at zero in all conditions.

(it's the z31 87-89 auto ECU)

anything else to try?

what about the O2 sensor line into your ECU? what is that measuring?

put the multimeter on pin 24 of the ECU, and it's reading approx 0.55V while the car is almost at temp and idling.

so, guessing the o2 reading address is wrong? any hints on finding the correct one?