Need some help

[trekmtbr89]

Application: RB25 neo in R32 Skyline running RB20det ecu with nistune.

So I need some help troubleshooting. a few weeks ago, I upgraded injectors to high impedance bosch 720cc from the previous high impedance denso 550cc injectors. Got it started up no problem after resizing injectors in nistune. I trimmed the AFR and it was driving fine. I drove down the road, parked it at advanced auto, and when I came back, the car would crank, kinda of catch, but then die. and then if I tried again it would flood.

I hooked up my laptop to find that it was pulling a DTC code for the AFM. This is funny, since I've never really had any issues with the AFM, and it's a good quality, genuine Z32 unit that I've been using with no issues for some time now. So I figured, ok, loose connection or whatever, got out, and made sure the plug was on tight, everything looks good. Went back in, tried to clear the code, and it's still there.

The odd thing, not sure if this is normal or not, is that nistune is registering a 326.900v MAF signal with the key in on and the car off. The is obviously not right. It reads this value with the maf plugged in and unplugged. When I turn on nistune, it connects up just fine, but makes three beep noises. like dit dit dah. I've never experienced this before, even while connecting with previous DTC's active. I'm assuming this is of importance, but I can't find any documentation regarding beeping noises in nistune and their meaning.

I've checked MAF voltage, ground, signal continuity, and signal grounds and I've measured the MAF signal voltage all the way from the MAF to the ecu pins, it measures 0.45v all the way there. So somewhere inside the ecu its being converted to some monstrous number that makes my ecu want to throw the MAF code. I am under the impression the car is supposed to still start up and run with a MAF dtc active, its just supposed to go into limp mode, but my car won't even start. It just floods if I continue cranking it.

At this point I figured that the ECU must be bad if the correct signal is entering the ecu, and the signal output from nsitune is so astronomical. So I purchased a new ECU, soldered in another socket and installed the nistune daughter board inside the new ecu. Turned it on, and I am getting the same exact thing.

So now I'm at the point where the only constant I can consider is the nistune board its self. Is this possible? Has anyone else had this issue before?

Edit: Note that when I got the ecu, I plugged it in first before I installed the nistune board, and I pulled codes form it manually, and I was getting the all clear code. So the ecu was good, once the nistune board was installed, I'm getting the AFM code again, like on the other board.

[trekmtbr89]

So today I brought my ecu to my buddies house who also has an r32. I connected up to nistune and confirmed everything was all good. Then swapped in my maf...tested..all good. Then swapped ecus, and immediately got maf dtc with the insane voltage again. I'm now convinced the problem is the nistune chip.

If someone could chime in I'd appreciate it. Is it common to have a nistune chip die?...sucks that I've gotta spend another 230$usd

[Matt]

Sorry not sure how I missed this post

I'll email you back with next things to check. Sounds like something got corrupted or messed up in the tune or BIN file in the board. Would need a reflash worst case