Ok so I'm stumped. I'm trying to get my 2001 turbo miata running. MS3 Pro PNP, fm stage 1 turbo kit, ID1050x injectors, dw 300 pump, flex-fuel sensor, gm iat, egr block off.

Long story short, injector 1 sticks open and will hydro lock cylinder 1 on crank and startup. through test pulsing the injectors I can hear 2, 3, and click, but not number 1. I pulled number 1 and hooked it up to a battery and a momentary switch, and it pulses fine with direct power, cleaned the injector to make sure it wasn't clogged/stuck open. I checked and made sure I had continuity on the black and yellow wire going from the harness plugged into the megasquirt and the injector pigtail.

Im stumped. iv also already paid a reputable tuner to set up the tune when we went for the first start is when we discovered the problem with injector 1 being hung open.

 

Is it wired weird?

 

Key on engine off not cranking do you have 12V across the 2 injector pins? Unplug the connector and measure there. If you do it's a wiring or tune configuration issue.

 

So I opened up the megasquirt, and it looks like there is some corrosion on one of the pins on the mosfet for the injector driver. We double checked wiring everything was correct. I’m gonna send it in to diy autotune. The car has never been driven on the megasquirt. It was never outside, I think i just got unlucky. Hopefully they take care of it.

 

I am doing the injector service for life last 6 years. It is very very unlikely the injector stuck open itself, especially the new Bosch EV14 injector.
Most likely the injector driver in your ECU keeps the injector open.