I just swapped a F20B in my accord from a F23A4 ULev with the F20B ECU and everything starts up and runs but I am getting a 12.5 drain on the battery when the ignition is not on.

i went through all of the fuses under the hood and on both sides of the dash and i still have have a 12.5 volt draw.... any help on possible relays bad? I unhooked the ecu, starter, and alternator and i still have a 12.5 draw...so i unhooked the power wire to the under hood fuse box and the draw went away so thats why im thinking its a relay stuck on... fuel pump still turns on when i turn the key to the on position. Any help is greatly appriciated!!!

 

Anyone?

 

so we went through and continued unplugging plugs connected from the harness to the the motor and nothing changed last night..... the only rewiring that i can think of that we did for the swap was to change the plug for the dizzy from 4-8 prong and we had to switch the prong on the ecu plug so that we could get the fuel pump to work with the f20b ecu after trying to start it with f23 ecu.... I dont know if it could be the main relay?! im running out of options to check..... i have done numerous google searches and forum searches and it seems like there isnt anyone that has had this problem but i still believe someone has ran into this before! (possibly on an H22 swap??) please if anyone has any suggestions let me know!!!! thanks in adance!

 

yeah, could be main relay, but there are a ton of things connected to the under-dash fuse box that you should be disconnecting to troubleshoot. And like 90% of hondas, yours probably has an aftermarket alarm, radio, fogs, gauges, or something that isn't ignition switched that could easily be draining it. process of elimination man, there's no easy solution there.