Car runs perfect with MAFS unplugged, WTF?

[timlush]

1989 240sx
S13 KA24DE fresh swap

With the MAFS plugged in, car runs super rich/idles like crap. Swapped in a known working MAFS and nothing changes. Unplug it and it idles perfect (obviously in limp mode)

I replaced the CTS with S14 KA sensor (had it laying around, not sure if they are the same). Nothing changed.

There are no vacuum leaks. All grounds are good. Timing is perfect.

What else could it be???

[jbuckley]

mmm well its like a fail-safe type thing.. when i blew intercooler piping in a place where it couldnt be fixed i just unplugged the MAF so i could get it home..

other then that i cant help ya just figured id throw that out there.

[slow92]

it sounds like it is in safe mode. try disconnecting your battery in order to reset the ecu. if this doesn't help than you might want to try and pull a code to see if anything pops up there. If no code, than you might have fried your ecu. this happened to me with my mines tuned ecu. I blew my maf and when that happened I fried the ecu and it would only run in safe mode and wouldn't let me rev past 4k

[renegade_ewok]

When in limp mode it runs off of a super safe map that is pre-programmed most likely. Check the voltage running to the MAF, maybe something along the line is screwed up. If thats fine, check the ECU.

[conwest]

i agree sounds like an ecu problem...