ok guys... im running 1300cc secondaries which have been bored out from my stock 850's (by rc engineering through rx7store) and an apexi pfc. recently my car has begun to stumble severely under boost at about 3500rpm and when it does all i see is thick black smoke coming out the exhaust. i believe that im choking the engine with too much fuel

i believe that my 1300's have crapped out on me and are just pouring fuel in. does anyone know if this has happened to anyone before and what the failure rate is on these bored out injectors is?

i havent made any changes to the pfc and am running the base maps. been fine before the 1300's and started acting up a month after getting them installed

any advice would be greatly appreciated, thanks

 

Is the PFC set for 1300 injectors? Also I know you might not want to do this but why don't you take out some fuel in the bogging rpm's?

 

yup i set the pfc for 1300cc injectors and it worked just fine up until a short while ago. i thought about pulling out some fuel but ill leave that as a last resort. but i dont really think that its the pfc's fault... i think that the injectors just went screwy. if i accelerate in first and second gear really gently then i can go up to like 6000rpm without any probs... im amusing thats because the secondaries only come online with boost, am i right?

 

ok ive got an update... it doesnt seem like its the injectors now... while driving and monitoring the pfc i noticed the inj duty is fine but the O2 reading is off the scale at 0.99-1.01v

what malfunctioning sensor could be sending false readings to the ecu and causing it to run so rich... keep in mind that this O2 reading is constant from idling to 3500rpm where the car stumbles and bogs. thanks again

im guessin it might be a bad O2 sensor or MAP sensor

 

Sorry I don't know too much about FDs but on FCs the sec. come on by RPM, not boost. I suggest changing the O2 sensor first sense that is a quick, cheap fix. RC Engineering is well-known so I have doubts about the injectors being bad, but I guess they could be. I really think you got on the right track though, looking for sensors instead of the injectors. The PFC hooks up to the stock O2 sensor, correct?

 

Did the large injector setting in your Power FC get changed back to the stock setting by accident?

Wade