Fueling Issues:Runs Rich/Can't Adjust Fuel/Idle with 850 Primaries/Injector Change
 

Hi all,

I'm fairly new the RX-7 community and just picked up an FD last month. As you can see, I'm having a few issues with my PFC related to fueling. The car is still on stock twins, runs 93 octane, has 850 injectors all around, and I don't have a Datalogit. The PO had it tuned by a reputable shop, there's no issues with WOT and high load but transients and cruise leave a bit to be desired (as is typical with tuners where dyno time = money).

1. The car idles and runs rich at cruise. I've tried messing with the fuel tables and have gone all the way in both directions and the lambda values do not change. A few cells show values other than 1.000, but is the table locked? Can I not make adjustments? I think I read that the tuner can change the base table to read 1.00 and the range of adjustment gets changed accordingly, is that correct? Do I need a Datalogit to get more range of adjustment?

2. On light loads, on initial tip-in, the lambda shows a lean spike (around 1.2) before it can recover add more fuel in. I've messed with the Accel Enrichment for the 1000 and 2000 RPM values and have added some fueling but can anyone share their Accel Enrichment values?

3. I have yet to check and adjust the TPS, and will do so, but I was thinking about switching the primaries back to 550cc and getting 1300cc for the secondaries. How much retuning will the fuel table need? Will I need to start the fuel table from scratch or can the PowerFC compensate for the injectors once it knows what the new injectors are? Not looking to drive hard, but want to be able to start the car and drive low load before tuning it properly.

4. Is there a way to adjust the idle ignition timing? The table shows BTDC values but idles with ATDC values which cannot be helping the idle. The car no longer has cats so I know it doesn't need the retarded timing to help warm them up.

5. I know that people have differences of opinions when tuning ignition split and keep these values very close to their vest but I'm looking for some advice. Other than at idle, there is no split timing. Not an issue to me per se, but the ignition timing seems to be fairly aggressive for something without split timing and for an ECU without knock correction. Can someone share a "safe" 93 octane timing table with and without split timing? I'd just like it for reference, to see what an aggressive table looks like.

Thanks in advance for your help. Loving the FD so I hope to keep the rotary running healthy!

Using 850 primaries is a pain in the ass. Very hard to get to idle lean and also transition properly.
Replace them with stock 550s or ID 750s.

I personally would remove them, and then beat the crap out of them with my 5 lb. hammer of death.