I was having problems with my KA24DE stock motor. Once it reached normal temperature, it would begin to putt, and than completely shut down. It had no power at all, it dropped to 500 RPM. I replaced the Mass Air Flow sensor and that didn't solve the issue. I than decided to swap the motor and tranny. It has the same motor, but is now a standard transmission. I've had the car back for one week now, and it is starting to act up again. The same exact problem. I connected a scanner to it, and it reads 4 codes. O2 sensor, Mass Air Flow Sensor, Crankshaft Position Sensor, and one other one that I forgot. All these are malfunctions. Does anyone have any idea if these would cause the problem? If not, are there any suggestions? Please help.

 

ok... so you replaced the motor with itself? and youre wondering why its still acting up?

heres something to try... if it idles, grab the engine harness and wiggle it while idling. see if the motor changes. and yes, those codes (if they are actual problems) would cause your car to take a ****. i think though that your harness is F'ed up

 

pick one forum and post in it. people will see it. check your other thread in 'engine swaps' for my reply.

 

yeaup please no double posting

 

The motor I replaced it with was from another 240sx. Would you suggest replacing the harness anyway?

 

if replacing the motor didn't solve the problem (which i think was a radical move to solve it, if that was your intention) try replacing the parts where you're getting the codes from, O2 sensor, MAF was already replaced, TPS sensor, Crank Angle Sensor. replace them one at a time so you'll figure out where the problem is. cheapest one is the O2 Sensor, try that first.