As title states I have a S4 TII with stock ecu, dude I got it from claims it has a half bridge port. I have a apexi safc installed and figured that's what was causing my problem. My car will not idle and has horrible horrible throttle response on lower rpms ~3500. If I add alot of(25%) fuel with the safc on the lower rpms it'll idle but still very bad throttle response. It also has 550primary 1000secondary. So my question is will a half bridge not run on a stock ecu and do I need a new management system like haltech, or do I have a problem with my primary injectors not providing enough fuel(clogged or went bad causing me to have to add more fuel to idle). Or something wrong with my tps causing my horrible throttle response. I'm clueless so PLEASE HELP

 

Yeah. You kind of need an ECU that you can tune. I've seen it done before with a stock ecu, but the guy did it only temporarily.

 

Half-bridgeported engines need radically different timing from stock, particularly at low RPM and partial throttle so I just don't see a way you can get it running well on the stock ECU. There's standalones floating around for as little as $500 (maybe less) if you are decent with wiring. You might even be able to get away with an Rtek, but I don't know much about them in terms of timing adjustments. The only time I had seen a bridgeport run on a stock ECU was in a race car being used for the 24 hours of lemons, so it was always full throttle.