So I am tuning a 1.6 Miata with a FM turbo system. The car has a DIYPNP, Eagle Talon injectors (at least based on the numbers on them and what I can find on the internet) which are 450cc, the injectors were cleaned and flow tested, Walbro fuel pump.

The problem is: once the car get to 2-3 PSI, it goes fully lean, at least that is what the gauge shows (very sudden, off the chart), and basically hits a wall. It certainly is not the amount of fuel in the computer (this is a map that was used for a similar car as a starting point, so it will be close). I have tried increasing and decreasing fuel to no effects.

What we have tried so far: different pump, gauge at the regulator is 45PSI through the entire drive and in boost as well. The plugs are gapped at 0.025 (heat range 6) and they are brand new. I know 7 would be better, but didn't have any handy right away.

Things we are going to try: change factory regulator and change fuel filter. Aside from that I don't really know. I can pull out the DIYPNP and check soldering to make sure there is no cold solders or anything. But it is very puzzling. Any ideas?

 

And to add, the boost cut is set @ 240kpa and we are no-where close to that. Up some of the hills it doesn't even get into boost (under 100kpa) and it just hits a wall. That's why it seems fuel related. Just don't know what.

 

is the ms actually seeing boost?
post logs/msq

 

It sure is. See about 170kpa. In any case, the problem has been found to be the DIYPNP, specifically the microsquirt board on it. I guess the injector drivers were destroyed by the previous ECU owner.

 

Could it be that the injectors are low-impedance?

 

The injectors are low-impedance. I wasn't aware that you couldn't use low-impedance injectors? I believe the RC set that was used was high impedance with the same result.

 

Ok, I see now that it can only handle two low impedance. I am fairly sure the RC ones here were high impedance, but will have to double check.