Boosted_97STO

I have a 97 STO Miata with 58k Miles. I finally decided to turbo my car earlier this year and it is still not drivable. Shooting for close to 250whp for right now. List of relevant mods below followed by my current issues. This car was completely bone stock and unmolested when I got it.

MS3 pnp pro
MAC Electronic boost solenoid
AEM X series Boost gauge
AEM Wideband
Kraken top mount 2560r
Kraken 3” down pipe, no cat, single exit 3” exhaust
Kraken 7” intercooler w/AC piping(2” hot side)
HKS SSQV4
NGK ZFR7F-11 plugs gapped to .030
FIC 1000cc injectors
ATI super dampener w/ FM 36-2 trigger wheel
99-05 crank sensor wired to factory CAS (FM and DIYAUTOTUNE said I needed the other crank sensor)
AEM Wideband
Deatschwerks DW300 Fuel Pump
AN lines from hard lines in engine bay to regulator and rail
Fuel Labs 515 fuel pressure regulator set at 43.5 without vac line connected (at idle vac it down to about 35-36psi)
Radium fuel rail
Radium pulse damper
GM IAT sensor kit
FM stage 2 cross flow radiator w/ reroute
Fab9Tuning Plug & Play Coil-On-Plug Conversion Kit
T6 5w40 oil
FM oil cooler kit

I have been working with my remote tuner via screen sharing sessions while on the phone trying to get the car to idle correctly. FIC states their injectors (even the large ones) can handle the small non linear pulse widths needed for smooth idle but that has not been the case for us. I had gotten larger injectors and pump expecting to upgrade my power goals in the future and run e85 but am using 93 octane right now with only a 250whp goal right now. What we are seeing is that the car will only idle smoothly around 11.2-11.5 AFR. Trying to pull out any more fuel causes it to surge and eventually die. My tuner has been working with FIC trying to figure out why the injectors are not working as they should but I am kind of over it all and am about to just switch to 650s and call it a day. My question is, could there be anything else wrong that could be causing my issues? My tuner seemed to have concerns with the fact that after shutting down the car, my fuel pressure drops to 20psi immediately and then drops off to 0 over about an hour. Fuel labs says the regulators are metal on metal sealing surface and that different people see different bleed off times. No matter how many times I prime the pump, my fuel pressure is no more than 20psi before starting. When running, the regulator is working as it should. So, is there an issue with my new regulator or is it just the large injectors.


Thanks,
Aaron

thirdgen

iTrader: (26)

Those are pretty big injectors for your goals...just sayin.

curly

iTrader: (25)

As I just responded in another thread, I haven't had any luck with injectors outside of IDs or occasionally Flow Force. If I were you, I'd abandon the FIC injectors and go with ID1050xs, not for their max flow rate, but for how well they perform at idle.

Your fuel pressure sounds normal for an aftermarket regulator. An OE regulator will maintain pressure for a long time, most aftermarket units won't. Unfortunately you can't change your fuel pump prime time on MS, but the standard 3 seconds should be plenty for it to build pressure, and then maintain pressure once cranking.

Boosted_97STO

Thanks for the reply Curly. I was able to get FIC to swap my injectors to the 650s which should fix my issues.