Strange Idle Issue/Idle hunting with large injectors
Posted: Sat Mar 23, 2024 2:04 pm
Yes I've read every single forum and post available online regarding idle hunting. I've smoke tested everything with all 3 sets of injectors I have.
TLDR. I have an idle hunting issue, but only with large injectors, if I throw my stock 240cc injectors back in and change the deadtimes back to stock it runs fine. I first had Hunter Tuned 1000CC injectors, and my tuner told me they were decapped and just hard to get to idle normally. So fine, whatever, I ordered FIC 1000CC injectors. Installed them, changed the deadtimes aaaaand exact same issue.
Car runs great while cold, but as it warms up the idle starts to slowly bounce around and then get worse. The only way to solve the hunting idle was to make the idle section a little richer than id like, and drop it down to like 10 degrees of timing. The rpm is steady now, but the AFRs still bounce from 12-15 at a solid steady rate. What's strange, is if I turn closed loop on it instantly solves everything. So it should just be a fueling issue right???? I have no idea, I've been chasing this issue for a month now.
Fuel pressure is set to 44PSI, with the car off. About 38 with the car running, vacuum line attached. 1997 Integra, entire car swapped to 1995 GSR OBD 1 harness with p75 ECU (don't ask, the guy before be was an idiot), B18b1, 9:23:1, BC springs and retainers, stock cams, stock intake, Go autoworks turbo kit, PTE5831, 3 inch exhaust, 4BAR map, DW200, AEM fuel pressure regulator. Heat range 7 plugs at .022.
Idle issue with rpm and ARFs all over the place. I drove around the block too
After changes to idle timing, Rpm steady, but AFRs still consistently bounce up and down.
At this point I'm grasping at straws, I have researched and spent hours trying everything I can find online. Also hot starts in this car are rough for a solid 20-30 seconds. Haven't even tried to fix that yet.
TLDR. I have an idle hunting issue, but only with large injectors, if I throw my stock 240cc injectors back in and change the deadtimes back to stock it runs fine. I first had Hunter Tuned 1000CC injectors, and my tuner told me they were decapped and just hard to get to idle normally. So fine, whatever, I ordered FIC 1000CC injectors. Installed them, changed the deadtimes aaaaand exact same issue.
Car runs great while cold, but as it warms up the idle starts to slowly bounce around and then get worse. The only way to solve the hunting idle was to make the idle section a little richer than id like, and drop it down to like 10 degrees of timing. The rpm is steady now, but the AFRs still bounce from 12-15 at a solid steady rate. What's strange, is if I turn closed loop on it instantly solves everything. So it should just be a fueling issue right???? I have no idea, I've been chasing this issue for a month now.
Fuel pressure is set to 44PSI, with the car off. About 38 with the car running, vacuum line attached. 1997 Integra, entire car swapped to 1995 GSR OBD 1 harness with p75 ECU (don't ask, the guy before be was an idiot), B18b1, 9:23:1, BC springs and retainers, stock cams, stock intake, Go autoworks turbo kit, PTE5831, 3 inch exhaust, 4BAR map, DW200, AEM fuel pressure regulator. Heat range 7 plugs at .022.
Idle issue with rpm and ARFs all over the place. I drove around the block too
After changes to idle timing, Rpm steady, but AFRs still consistently bounce up and down.
At this point I'm grasping at straws, I have researched and spent hours trying everything I can find online. Also hot starts in this car are rough for a solid 20-30 seconds. Haven't even tried to fix that yet.