S13 - Dieing When Shifting

[Gokussj5okazu]

Hey guys, finally got my S13 running and am trying to iron out all the kinks before I start dailying it next week.

Right now I have two major issues that I believe are related. A little back story first though. I have done a complete EGR/Emissions removal, as well as the Air Regulator. I still have the AAC/IACV valve though. I have checked the entire system for vacuum leaks up to 20psi. Nada, it's sealed up tight. Otherwise it's stock.

I have already pulled the entire intake apart and cleaned everything including the AAC thoroughly.

1. When you start it up, it idles great around 1100 for the first few minutes until it starts to bring the RPMs down. Then it will consistently idle about 800, but has a slight and random misfire. There seems to be no pattern to it at all. And also it will occasionally dip down around 500rpm, shutter a bit, then bounce back up around 1000 then to 800.

As per the FSM, I tested the O2 by unplugging it once the engine was warmed. It shot up around 1200rpm, then back down to 800. The misfire was still there and it occasionally dropped to 500ish.


2. When driving, when I let off of the throttle between gears the engine instantly drops to around 500rpm. Some times it catches itself and jumps back to 1000, some times it dies.

Suggestions?

[Mitsubayati]

All symptoms of EGR delete. Engine is now running rich.

If you have the stock intake tube, are there any holes in it that are open to atmosphere? There is one on the bottom that I think runs to emission components. If vented it won't cause obvious problems but can cause the symptoms you described.

[Croustibat]

It sounds like a boost leak, but it could also be your IACV is sticky. Also check if the gearbox neutral sensor is working, that one commands the IACV to open a little when there is engine load and no gear is engaged.

Also i don't know the engine you have, if it has a turbo and a BOV ... know that most if not all BOVs leak at high vacuum unless recirced, and that is exactly what happens when changing gear.

[NISR20MO]

Maybe I missed it but what engine?

IF it's a KA24DE it is probably the IACV. The symptoms match.

[sleeper108]

Already Mentioned, But IACV, and BOV re-circulation.

My car had the same symptoms since day 1. It's track only, so I never really fixed the BOV re-circulation, just did some tuning to keep it from stalling itself, and changed out the IACV.