Nissan Figaro MA09ERT Engine SWAP

Hello all,

I'm working on a Nissan Figaro that I did an engine swap on. I've been working steadily on this for the last 7 or 8 years.  The car is a Nissan Figaro built on the Nissan K10 platform which was only available in mostly in Japan, Canada and Europe.  The engine is out of the JDM only March Super Turbo with the MA09ERT engine.  The engine is both Supercharged and Turbocharged from the factory.  As the car does not have any useful diagnostic port, I had to build my own breakout box to intercept the signals from the sensors to the ECU.  The car uses the RPM and MAF signals to deliver fuel.  I've added my own MAP sensor and Fuel sensor to read the pressures in both of those systems. I've also added a sensor to read the supercharger bypass valve to ensure that it's opening.  I'm using two Innovate SSI4 and their LC2 controller to log the data.  The SSI4 allows for 12 hz for data acquisition.  Here are the signals I am currently monitoring.

MAP
MAF
Fuel Pressure
RPM
Water Temp
Throttle Position
Bypass Valve Position
Injector Duty Cycle on Injector 1 or Water Temp

What's happening. 

• Car runs very lean, between 18 and 20:1 during idle, 
• Car runs lean on boost, between 18 and 20. 
• Stumbles on Acceleration
• Backfires through inlet

Observations

• Fuel pressure is steady at 2.7 kg/cm2 (factory requires 1.5 kg/cm2 above MAP so it's often 0.2 kg/cm2 above expected)
• Fuel pressure modulates based on MAP very consistently at 1.7 kg/cm2 (0.2 higher than expected)
• MAF is right in the middle of the OEM expected values (1.2-1.5 V at 750RPM & 1.8-2.1V at 2500 RPM)
• The idle-up solenoid always seems to be active. This particular engine is only supposed to use that solenoid under the following conditions (Headlights on, heater on, defrost on, voltage <12V).   If I disconnect the idle-up solenoid, the RPM drops by 200 RPM and it idles very roughly
• If you turn the lights on, because the idle up is already active, the RPM drops by another 200 so the engine is really falling flat. 

Modifications (beyond the swap itself)

• Aftermarket exhaust w/ cat delete
• Factory O2 mounted in the Turbo Manifold
• Aftermarket exhaust had O2 bung added for the wideband
• Fuel Pump swapped out to Walbro 255 (no reason beyond people saying the issue might be your fuel pump)

What I've checked So far

• Removed the vacuum reference line to see if the exhaust richens.  Seemed to increase from 20:1 to 18:1 but it's nowhere near 14 or 15 at idle
• Built a smoke machine to test for intake leaks.  No obvious leaks located
• New Sparkplugs (just because it was easy before I put the engine in.
• Swapped out a previously used fuel pressure regulator, no appreciable change in Lean conditions, still runs between 18 and 20.
• Had a friend bring over his oscilloscope and we briefly monitored the Injector signals from all four injectors.  They were all offset by the expected 90 degrees.  Beyond that, I'm not an expert at deciphering that beyond the fact the control signals all work at the ECCS

I can provide the Innovate logs over DM, e-mail.  I created a detailed wiring diagram of the swap between the Figaro's MA10ET and the March's MA09ERT.  I can share that if requested.  I don't really know where to go next.  I have a complete spare engine and my gut feeling is that the issue is fuel related versus the MAF being faulty since its providing the correct readings at the ECU.  Given that removing the vacuum reference didn't change the O2 in the exhaust despite the massive jump in fuel pressure, maybe that leads to the injectors.  Looking for any wisdom the Internet might have to me.  Many thanks in advance.   

-Christopher