I have a 94 del sol vtec stock b16a3.....car was running and idling perfect till one day I pushed started it when my battery died and had no cables. Ever since then it started reving up and down between 1000-1500 rpm sometimes even dies on me.... Car still runs and hits vtec perfect but at idle it bounces up and down....I did a full tuneup , it got a little ether but didn't go away....yesterday I let my friend borrow my p30 Ecu for CA reff, and I borrowed his p72 gsr Ecu and it fixed the problem, when u put the p30 back on the problem returned, my question is there a way to fix the Ecu? Nothing smells burnt or anything, I know these are rare and expensive so I'm trying to go the easyiest way out .any help will be appreciated

 

Sounds like you're having the same issue I'm having with my D16Z6 with its P28 ECU. Car ran great for a few years, then magically the idle started bouncing. Otherwise the car accelerates well, but at idle it was 900-1400 rpm. Thought it was a host of other things, but learned it was my ECU.

I honestly don't know if your P30 can be fixed. I picked up a used P28 for next to nothing, after the dealership wanted over $800 for a new one. I imagine a P30, mated to a B16 motor, will cost a bit more brand new.

 

i have a swapped d16z6 with p28 in my del sol as well. can't figure out why the idle is bouncing too. i have unplugged the IACV and now it runs great but with a CEL..think i should try swapping a p28 in? i hope thats the answer

 

clean your iacv and fitv with carb or brake cleaner. i didnt see you mention that

 

The P30 and P72 ECU's use completely different idle routines / coding within the ECU's rom. More than likely it is an issue with your IACV or FITV than the ECU itself..

 

True, I didn't mention that, but I did clean it , I actually stripped my whole intake manifold, throttle body and cleaned the **** out of it and it still idles bad...would a p72 Ecu work to pass smog on my b16? That's the only thing I'm really worried about right now ,since the p30's are running pretty rare now and pricey