Nistune Forums

i have a z32 afm installed. i removed the resistors on the main board to remove the voltage offset when i used a romulator.. i have also removed the afm voltage offset from the nistune adr file.

at idle i have approximatly 2.7 volts, and at 10 psi on my 50 trim t3/t4 the voltage hits 5.3.. something seems very wrong here.. i figured i would be idling at a much lower voltage, and i figured that i would not be maxing out the afm with such little airflow. what is the problem here?

is this being check with a multimeter or is this the nistune reading?

Some questos:

What year ECU are you using?

Where is the voltage being measured from? AFM/ECU plug or NIStune readout?

What is the voltage readout from NIStune when engine not running (should be 0 volts)

Is your AFM readout in the address file AFM_OFFSET=0?

What is your K value set to?

Matt wrote:Some questos:

What year ECU are you using?
its an 88 turbo ecu

Where is the voltage being measured from? AFM/ECU plug or NIStune readout?
im just looking at the display in the nistune software.. when i have time i can measure it from wherever you want me to.

What is the voltage readout from NIStune when engine not running (should be 0 volts)
with nistune connected and the ignition on, the AFM does NOT read 0 volts, it reads 1.85 to 1.87 volts...

Is your AFM readout in the address file AFM_OFFSET=0?
thats exactly what it says

What is your K value set to?
its at 300 right now which seems to work pretty well.. im sure there is still some fine tuning to be done though..

on another note, the battery voltage display in nistune reads between 3 and 4.5 volts with the motor running... please let me know if you have any ideas. the way it is now, my AFM is over 5 volts before the car even gets into boost.

edit: i forgot to mention.. im also having a problem with injector latency.. it does not matter what i set the value to, it does not change how the car runs.. ive had it set at 5 and at 255 and almost everything inbetween.. there is absolutly no change in afr or anything else for that matter.. when i change the K value the change is obvious, but with latency, nothing happens at all.

ok so to install a z32 MAF (i just purchased one)

you need to remove the resisters and change the address file? (how do you change that?)

i guess this is the resisters your talking about

http://www.redz31.com/pages/fuel/afmcrap.html

on another note, the battery voltage display in nistune reads between 3 and 4.5 volts with the motor running... please let me know if you have any ideas. the way it is now, my AFM is over 5 volts before the car even gets into boost.



*** I had the EXACT same problem, Actual Voltage on the display was between 3 and 5 volts. We thought this didnt have an affect on anything and that the display was wrong, but later realized its a mistake that matt has fixed (I have a 87T Board).

The voltage being this low caused the injector offset table to be WAYYYY off (firehawk told me this) and we couldnt tune the car cause of it (ran SO crappy I didnt drive it for weeks).

But its been fixed here:
viewtopic.php?t=321


* I dont know much but just wanted to point that out to you.

i saw your problem.. the thing is, i have an 88T ecu.. he says the problems are with earlier ecus.... plus i have the afm voltage issue.. im sure all this is related to either a defective afm, defective nistune or a defective computer or some combination of the three, but i dont have spares to experiment with.. basically im stuck until matt is back from vacation.

Hi Chris

We found the 1986-1987 ECUs have a different memory location for the battery voltage compared to the later model Z31 ECUS. So I had to update the firmware for those boards.

But your board should be for a 1988 ECU. If it is for an earlier ECU that could be a problem. Can you please let me know what ECU ID and REV are displayed in the main bar in NIStune? I can test that version out tomorrow on the bench. If it is the wrong year, I can send you a replacement board out with correct year/updated firmware

The AFM voltage I will need to looked into further. NIStune should be reading the same voltage as one of the legs on the HD46510 chip which comes after the resistors you remove. I'll look into that tomorrow when I get back

In regards to the latency... there is a latency at 14V and another adjustment below this voltage. See the thread below and add the line to your address file (open the address file in a text editor and add it)
viewtopic.php?t=357
or email me and I can send you an updated address file

Let me know if adjusting this value changes things also. I'll double check your ECU ROM code latency value is the same as the others

Just looking at the ECU today the HD46510 chip uses pin 40 for the AFM input. Whatever voltage is on this pin is what NIStune displays on the screen.

You can check this voltage by using a multimeter and putting black probe against ground (I usually stick it in the injector plug where one of the black wires are) and the red probe on pin 40.

NIStune will display the voltage from this line and add LEGACY_AFM_OFFSET value to it.

When removing the resistors, and changing LEGACY_AFM_OFFSET to 0 it should read between 0 and 5.12 volts in NIStune as per the pin on this chip

You can then check this against the input voltage. I only have the earlier type 1986 style ECUs here currently. But thats what I've been measuring on the bench

I have emailed you an updated address file

I'd be interested in what K value you guys are have before/after the Z31 to Z32 MAF upgrade.

That way I can fine tune the HP readings for the MAF change list to get them more accurate.

012F for bosch/ford cfi 440cc injectors/z32maf.

thanks for that

with the latency issue... please see updated address files. values are different dependent on Z31 year. i've emailed an updated file

viewtopic.php?p=1773#1773

suspect will need to exchange your board. sounds like you might have 1987 firmware in there which reads batt incorrectly. doesnt explain MAF readings however. wiring diagram and instructions for diagnosis emailed