need help car won't rev past 2.5k rpm

[kamikazee47]

i just got my ecu tune for 555cc and z32 maf,

after i got my ecu back i install the ecu and z32 maf. after install the ecu and z32 maf my car won't rev past 2.5k rpm or so and when i give it 100% throttle it won't rev at all. could this be that i wired up my maf wrong?

ka24de has 3 wires Blk/slv= 12v W=.5v BLK=ground

Z32 Maf Wires Thick White wire = 12v (2)BLK=ground Not so thick white wire = .5v

I solder those wires together i connect the 2 ground from the z32 directly to the ka24de black wire so i did not ground one to the chassis.

did i wired it up correctly or no?

[coolbone28]

Chances are you wired it wrong. You could try grounding to the chassis as well. I know some people have had trouble with the grounds before, but it changes from person to person.

[kamikazee47]

is it just the ground? or everything? i'm pretty sure i connect the right 12v and .5v right i used jwt guide.

[kamikazee47]

the odd thing is when i hook up my afc up and set the in and out to 2in2out it would rev smoothly until 3.4k rpm that is with the lo map set to -50 across hi -50 acorss

[WDRacing]

Read the wiring diagram in the FAQ. The N62 MAF has 2 grounds, one goes to the ECU, one goes to the car itself just like any standard ground. Then there is a power and a output for the MAF. Total of 4 wires...

Here's the link. 300ZX MAF Wiring

[kamikazee47]

That is what i used but i didn't ground it to the chassis but instead just connected both to the ground wire from harness

[WDRacing]

Some people have had luck with that, I myself did the same thing you did.

If the car desn't go over 2500 it's because the ecu is in limp home mode. MEaning it either needs reset or the MAF is fubar. Can you check the maf output voltage at idle? When mine was toast it read 3.6v at ilde, which is obviously wrong. Since 5v is the max...lol.

[kamikazee47]

how do i check the output voltage

[zerepdivad]

Sounds like the same thing that happened to my friends car when the mafs was unplugged by accident. It wouldn't rev past 2.5 grand.

[WDRacing]

If you have a SAFC it will tell you, if not you'll need a multi meter and you tap the output signal.

WD

[kamikazee47]

the afc show In-1 1.5v and In-2 .035V

[WDRacing]

2 inputs? Mine showed just the MAF reading.

[kamikazee47]

where do i go in the safc to check my maf reading?

[kamikazee47]

does it matter which ground from the z32 maf i use to ground it to the chassis?

[kamikazee47]

could different size injector cause this problem? i did some research today and notice that nismo 555cc part number is 16600-RR543 and 740cc is 16600-RR544also notice the different color 555cc is yellow, and 740cc is red. and i believe i have 740cc not 555cc by looking at my nismo injector box part number. so i want to say the injectors are causing my problem and that my ecu is tune for 555cc not 740cc. can someone verify this.

[eazye2000]

Keep in mind, that the JWT diagram has you looking at the plug as if it were plugged into the MAF. So basically like you're looking at the MAF. NOT looking at it to where you can see the prongs/plug. Look at it from the wire side.

I doubt that makes sense, but hey... I tried..

[kamikazee47]

i came to conclusion that it wasn't my wiring but my ecu and injectors. my ecu was tune for 555cc and i just figure out today that i have 740cc injector .

[kamikazee47]

that was why i was able to rev it past 2.5k with the safc on and with the fuel correction set to -50 lo/hi