Car only starts with OBD2 scanner attached???

Okay fellas.. I got a major problem i cant seem to figure out.. My friends 2004 civic need a rebuild due to a spun rod bearing..okay i finished the rebuild and reinstalled everything..i go to start it and it starts right up ...it runs for about 45secs to a min then shuts off...i go to restart it and it just turns over..now while trying to restart it...im hearing the relays behind the glove box clicking away like crazy...so i connect my obd2 scanner to see if i can pull any codes..no codes pop up..so then i try to start it while the scanner is still connected and voila....It starts and idles like a champ...now while it is running i decide to disconnect the scanner and it dies..go to restart it ...it wont start...reconnect the scanner and once again it starts no problem...does anybody have any possible reason for this??? i did some research and cant find anything...thanks

ohhh...and the car started and ran fine before the rebuild...

I'm having the same problem on my 01 Toyota echo.. I installed an hid kit on it and it started acting up. Did the same thing. Use a scanner to check for codes and no codes where shown. Started the car with scanner connected and starts good with no issues. There seems to be some kind of short. Maybe if check the wiring on your rebuilt and I'll check my bixenon set up.. keep you updated.. good luck..

Okay fellas.. I got a major problem i cant seem to figure out.. My friends 2004 civic need a rebuild due to a spun rod bearing..okay i finished the rebuild and reinstalled everything..i go to start it and it starts right up ...it runs for about 45secs to a min then shuts off...i go to restart it and it just turns over..now while trying to restart it...im hearing the relays behind the glove box clicking away like crazy...so i connect my obd2 scanner to see if i can pull any codes..no codes pop up..so then i try to start it while the scanner is still connected and voila....It starts and idles like a champ...now while it is running i decide to disconnect the scanner and it dies..go to restart it ...it wont start...reconnect the scanner and once again it starts no problem...does anybody have any possible reason for this??? i did some research and cant find anything...thanks

ohhh...and the car started and ran fine before the rebuild...

Check the ground cables. That was my problem on my hid set up. A ground wire was not properly connected.