Subaru Conversion Won't Idle Options

[turnaround89]

Hi everyone, so December 2018 was the first time I got to hear the WRX STi motor I purchased run. It ran rough because the intake wasn't connected, hardly any sensors hooked up, etc. However, it ran and that made me happy knowing my investment wasn't useless.

The engine that was purchased is supposed to be a subaru wrx gc8 sti v4 turbo ej20

Cut to a few months later, now I have all the required sensors (MAF, purge solenoid, ignitor, etc) that I was missing purchased and hooked up. Vacuum hoses hooked up and I thought now the engine should run and idle beautifully. Nope, it will fire and run for maybe 3 seconds then shut off. Check out the video in the link.

Subaru Engine Video

The only thing I dont have hooked up are to the non-pressure side of the intake. I tried plugging these holes today and the car did t idle any better. Now, I need to find a permanent solution to these holes, but I swear the engine is running worse now with everything hooked up then in December with nothing hooked up.

Any ideas where I could start?

I was thinking fuel pressure and timing would be my next step. In the video you can hear the fuel pump prime the system before the engine kicks over.

The wiring harness was sent out to iwire services to be redone and that appears to be functioning properly.

Thank you everyone for your help.

[turnaround89]

Hi again everyone,

So I finally have the bypass valve recirculating back into the non-pressurized side of the intake. The idle air control valve is now correctly pulling from the intake as well.

Fuel pressure is roughly 40-42psi on start-up and holds pretty constant while trying to idle. Fuel pressure does increase with increased revs which makes sense due to the boost controlled fuel pressure regulator on the car. I don't believe I am having a fuel pressure issue.

I believe something else is going on related to a sensor, just not really sure where to start. The MAF is newer (used, but from a 96 EJ20 GC8). From what I can see all the sensors I need are hooked up as I don't have any extra connectors on the ECU harness.

Below are two videos, 1 where the car fires up and attempts to idle, but shuts down quickly. The second is my hitting the throttle showing the car revs strongly, but once it returns to idle, the engine shuts off.

Subaru WRX Idle Issue
Subaru WRX Engine Revving

The engine is pulled from the vehicle to make tracing this issue, hopefully, a little easier. This also makes working on the engine easier overall. That is the reason for the mess of wires going everywhere on top of the engine, I don't have anywhere to organize them except to sit on top of the intake.

Still trying to track down this idle issue, any ideas are greatly appreciated. Thank you all!