BAD MAF???

[BigPar]

Okay my RB25 starts and runs in my S14. I don't have intercooler hooked up, so I'm running it NA with the MAF and filter put on the intake manifold pipe. I may have a few small vacum leaks but shouldn't cuase this.

(knowing the tach not being correct obviously)

The car sounds to idle correctly and smooth (at 1800rpm on incorrect tach signal) I rev it out and it hits about 3500rpm and bogs/bounces off that rpm when holding full throttle. Isn't a fuel cut or rev limiter sound as if I was hitting redline. So I unplug my MAF. Car runs exactly the same and does exactly the same thing when revving it out. Is ther anything that would cause my engine to do this other than a bad MAF? Have I maybe forgotten some sensors plugged in? There is part of the harness the MAF and ABS sensor plugs are on that has other plugs I do not know what belong to. Your help please.

[Joe]

finish the swap (do your ic piping)

then troubleshoot.

[Darius]

You can check the MAF wires for continuity to the ECU and to ground. That should get you half way there. Did you extend the wires at all yet? If so, did you shield them? I know these probably won't have an impact on the way it is running right now, but I'm just making sure you have that in mind.

I have also heard that if you do not have your neutral position switch wired up properly, the same symptomes will happen. I.E. not being able to rev the motor. That is hearsay so I am not positive on that one. I'd check your MAF wiring according to the FSM first, then report back to us.

If everything checks out and it still runs crappy, finish the swap first

[RB280SX]

Have the same problem with my 240sx. Now that I think about it, I'm 99% sure that it's the MAFS because when my SAFC is hooked up to trick the ECU, I can rev freely...