Hey guys as the title says I swapped a new to me(about 50k miles) into my g as my old motor was getting worn out at 230k miles, It was a jdm motor so i swapped the harness, power steering pressure sensor(new one), oil pan(old one as new one got a little bit dented from shipping and old one was mint), oil pressure sensor(new one), crank sensors and cam sensors(new ones), throttle body and 02 sensors. Maybe relevant info is that i also changed my clutch, flywheel, pressure plate, steering rack. So yesterday we got to the point of the motor being in and the front end not being connected not even a belt on just the things needed to start and technically run the car(like all harness connectors that came off with the engine, trans, grounds, etc), it started first time and sounded pretty good but died like a good 15 seconds into the idle, we tried starting it again and got it started again but anytime we revved it, it would just essentially stall and die after trying to return to idle. I heard that it could be a throttle body relearn i did the accelerator and the closed valve one i believe but the last one(forgot the name but its the one that requires you to press the pedal 5 times and stuff) im pretty sure you need to do while the car is at operating temp, but the problem is car can't even stay on long enough to do that. Today I bolted up the front end and connected all hoses and such else, basically the only connector not connected is for the orange lights on the bumper. I put the battery back on and went to start the car, it started for maybe about 2-3 seconds got to about 500rpm off the intiial crank over(i think thats the right word basically the initial rev the car does when the motor ignites on), i double checked the grounds and the connectors in case if anything was loose somehow from me putting on the front end, they're all tight. I tried starting the car again but it wouldn't even crank over after the first time, i think it did maybe one or two more times but it died essentially like the first start of the day. My guess is leading towards battery or alternator even though they were good before hand, they could've been drained from us starting the car multiple with about 8-12 connectors loose(like the front end and lights stuff) the previous day as well as just not being on for about three weeks. Also yesterday the car started better and ran longer and ran long enough off the first initial start that the battery light was on, im pretty sure the slip and vdc light were on but that could be either from my tierods not being connected yet or me replacing the steering rack or the throttle body needing to be fully calibrated. I'm gonna get a battery tester from my friends shop tomorrow to test the alternator and the battery to see if its that, but is there anything else I could be missing any help would be greatly appreciated!

 

Also forgot to mention I have motordyne art pipes, z1 intake, z1 exhaust, and some other odds and ends(not like plenum or anything) as well as being tuned on 93 by admintuning. I did not reflash the ecu with any new tune(im pretty sure it carries over even though I disconnected the ECU as its written onto the ecu). Just more info if that helps at all

 

When you put the flywheel on you aligned the dowel pin on the crankshaft to the hole in the flywheel yes? Same flywheel as before?

 

If so I would suspect you got a couple coil pack harnesses swapped.

 

Are all of the major sensors plugged in, like crank and cam shaft sensors? Bad sensors cause the car to shutdown weird.

 

You my sir are the winner winner chicken dinner! I didn't see any of the replies before going and checking my flywheel but my flywheel was installed incorrectly, reinstalled correctly, first start was the best the car has ever sounded sounds smoother than silk feels. Haven't gotten it on the road yet since i just did that work last night but idles fine and no codes so far!

 

All of them were replaced by the time i wrote the post but you are right the crank and cam sensors would cause this issue and should be one of the first couple things anyone who has this issue should look at. Thanks for your help!

 

Awesome glad you got it all figured out.