240sx won't idle after 93 to 92 engine swap

[Steven Lee]

My motor was smoking in my 93 240sx so I changed it out with a motor out of a 92. When I try and start it, it revs up for a sec and dies. If I start it while holding down the pedal, it will run as long as I do. As soon as I let go, it dies. I noticed that there are a couple of differences in the 92 and 93 motors. I changed the throttle body (because the tps wasn't the same), but is there something else I'm missing? Do I need to swap computers as well?

[Mastacalus]

Check all vacuum lines, make sure there are no leaks, but most importantly, check that none of the metal lines have build up in them, it happens to motors if they have been sitting for awhile while pulled from a car (EI: If you buy a motor from the junkyard to replace your old motor, it could have crud in the lines) get an air hose and blow them out, happened to my car when I had to replace the motor aswell. Check TPS and make sure everything gets good ohm reading for grounds aswell.