JeffBro

Background on the situation: I had noticed that after I swaped in a b18c jdm gsr into my 96 EX civic while driving at night all of my lights would intermittently dim and get brighter randomly.

Well eventually after driving it for a long time I noticed that it wasn't dimming randomly. It would do it when going from deceleration in gear to accelerating. It always seemed to be linked to the throttle. I checked the alternator and that wasn't the cause.

Now present day. I was talking to a mechanic at the shop and he suggested that maybe thats how the system works. He proposed that maybe the computer was telling the alternator not to charge when you are accelerating and would only go to full charge mode when decelerating in gear(basically only the momentum of the car is turning the engine). This would allow the engine full pony when under hard acceleration and also possibly better fuel economy because of less drag on the engine overall. Tested this theory out by swapping a USDM gsr ecu and sure enough thats it! Only the JDM ecu offers this feature. But thats how it works. Great idea from the honda engineers.

kayelemenohpee

which is that? i have a p72 but im pretty sure i should got with a p28

marquisdee1018

I noticed that my car does it too. I'm running a jdm d15b with a p08 ecu. I haven't tried a usdm ecu to see if it makes a difference. I always thought it was just something electrical wrong with my car.

sicones

how would an alternator that is not charging have any benefits for acceleration, if anything less output from the alternator while accelerating would cause drop in voltage and weak spark

994door

I had the same problem when i did my swap (jdm b18c). I ended up cutting a wire and it fixed the problem. I read it on hondata somewhere.

CapnKrunch

I noticed that my friends gsr swapped ej7 with a jdm type r ecu does that! I always wondered why it did that, but never took the time to look into it. Good info.