92 240sx ka24de mafs problems

[Tims_240]

I did an engine swap in my 240 and now I'm having problems with my Mafs. I hooked up a nissan consult to my car and when I put the key in the "on" position the mafs reads 5V which is max voltage. When I start the car the sensor still reads 5V, and the car stumbles alot, but will still hold an idle. When I unplug the mafs the engine smooths out and holds a steady idle of about 1100 rpm. Which would lead me to believe that the mafs is bad, however I have taken a mafs off of a running 240sx and it does the same thing. I have tried grounding the mafs wire to the chassis and the idle gets worse. I have tried another used ecu too and the car acted the same way. The ecu only throws code 12 which is the mafs, and no other codes. I am stumped but am hoping someone could help me out.

-Tim

[Felipe]

check for corrosion on your cennetors

or maybe its just your idle screw?

[Tims_240]

I was thinking it might have something to do with the TPS, however the only code I get from the ecu is 12.There is no corrosion on the connectors that I can see. The mafs works, but when I pull the plug out, it runs better than when its plugged into the mafs. What would cause that to happen? Would a bad ground have something to do with the MAFS seeing 5 volts at all times?thanks guys.-tim