Civic EG

So on my buddies 1994 civic dx with a z6 swap and JRSC on it he asked me to install his new injectors and resister box. i did that and car runs well after i static timed it a bit better but it wont rev past 4k im thinking its in limp mode?? it throws code 20 which i dont know why the reister box i tried two one i knew worked, everything seems to be wired correctly so i really am at a loss here never experienced a code 20 and ive wired in resister boxes alot.....

Any help would greatly be appreciated.

Code 20 has to do with the Electrical load detector

This is a small box in the underhood fuse box that North American civics came with (not sure of UK but JDM did not have them)

What it does is sense a change in the draw of the electrical system and adjust voltage accordingly, however they are somewhat fickle and get out of whack easily when there's a problem.

Are you 100% sure it is a code 20? A short will cause it. Check your alternator fuse too.