Running on 3 Cylinders
 

Hello everyone,

I am having an issue after wiring up my injector harness for sequential injection on my 1990 1.6. I unpaired injectors 3 & 4 and wired them up to pins 2Y and 2Z respectively on the ECU connector. After that I started it up and noticed immediately that I was running on 3 cylinders.

I started up test mode and tested each injector and found that INJ D (Cylinder 2) was not clicking. I measured 12V at the injector and have continuity from the injector to pin 2V on the ECU connector.

Right now I can only think of 3 culprits:
1. Bad injector driver (unlikely as the battery was disconnected the whole time)
2. Stuck injector (it was working fine when wired for batch injection)
3. Firmware issue

Does anyone have any input on what could be causing INJ D to not work anymore? For reference it is a MS3 Basic from MSLabs on version 1.5.1.

Swap injector to new position. Report back

F'ed up wiring. Recheck LATER, report back.

Thanks Ryan, I swapped the injectors out and ruled out that it was not a problem with the injectors.

I think the pins on my ECU connector might be different from what I see online. I used this diagram:

https://cimg2.ibsrv.net/gimg/www.mia...ccc8f3c948.jpg
For example, when I am in testmode and pulsing INJ B, it is sending pulses from pin 2V when that one should be INJ D. Is there another pinout for a 1990?

Okay I finally figured it out. Huge shout-out to Savington in this thread: https://www.miataturbo.net/megasquir...3-basic-94921/

I had to move jumpers JP10 and JP11 to the dual-dot position and now everything is working perfectly. Wish I had tried that before I took apart my injector harness a second time!

I was a little hesitant to open the case because I didn't want to mess anything up. All I needed was a T8 driver to open it up, and then I saw how the injector drivers are linked to the pins. It all makes sense now, thanks!

Excellent