Another car with idle issues
 

Background:
Car is a 2015 Subaru BRZ Limited. Currently, my only modification is the Edelbrock Supercharger. Also, I don't know enough to help myself (car n00b).

Areas of Concern:
DTC Codes - P0172 (rich bank 1), P117b (direct injector), P1170 (port injector), C1201 (?), B14A1 (?). Fuel trims are way off (LTFT is -30% at idle) and AFR is all over the place (12-15| doesn't hold near 14.7). Traction light in the middle of the tach is always on.

Main Issue:
The rpm will drop to about 600 then go up to about 1500 then drop to 800 and repeat. Sometimes the rpm drops low and the car turns off. The problems existed with no DTC codes or CEL for a while.

Repair Journal:
12/13/2019 - I took the car to a shop last week. The guy couldn't find any exhaust leaks or vacuum leaks, but was witnessing the idle fluctuation/hunt. Rescheduled for a day he had more time.

Update Journal:
12/15/2019 - Over the weekend, the traction light turned off on it's own. The P0172 rich bank 1 is now gone. Fuel trims are still not normal from what I'm being told, but are better. AFR is no longer bouncing all over the place and is behaving normally. The other injector codes, and the two unknown codes are still there. Car no longer sluggish. Also, is finally quiet like it should be with an OEM exhaust system. I feel like all signs point towards fuel system. Going back to my mechanic tomorrow.

**12/17/2019 - Car was inspected for about 5 hours at the shop. Mechanic did not have enough time to check my car properly last week. He could not find any reason as to why the car is having idle issues. Mechanic confirmed my observations, and states the car is doing better at idle than last Friday. He is completely stumped at the moment. He states that unlike last week, the car seems to be doing fine while being driven. He suggested that I reach out to the manufacturer as he thinks this is a tune issue. I hope it's a simple fix where Edelbrock has a secret revised CARB tune that fixes all of this, but I doubt it.

Data Log:
12/15/2019 https://datazap.me/u/djenousis/12152...17-20-26-27-37

Stuck injector or faulty bypass actuator for the SC. Did the problem pop up suddenly or was it right after you got the SC installed?

Good plan. If he can't get it settled down, I suggest you take it to a different mechanic/tuner.


humfrz

It kind of popped up suddenly... It's interesting that you mention bypass actuators, because it all started around the time my actuator was replaced. The new bypass actuator solved a similar problem, but then gave me my current problem. Thanks for the lead I'm gonna look into what you said about stuck injectors.

Oh..it’s unlikely a stuck injector then..what was your problem before? Who installed the actuator? I’m pretty sure the arm of the actuator needs to be oriented in a specific position as it can affect AFR and such.

I mentioned the bypass because it’s a very common part that faile on the Edelbrock.

I had the same issue (with my Sprintex kit). Very similar codes and it turned out to be the bypass actuator. Good luck!

Thanks. I got the car back right now. The mechanic was stumped, and suggested that it might be a tune issue. Unfortunately, this issue has occurred while using the CARB tune and a DT tune. I guess progress was made, because now I know it's not a vacuum or exhaust leak and that my o2 sensors are fine.

Since you're in Torrance, the Edelbrock factory/headquarters in Torrance as well. Maybe you could stop by (email first) and see if an engineer/specialist might chat with you for a bit.

Any updates?

OP any updates? Having similar issues

Somebody HAS to resolve this issue. I have literally opened 50 threads with people having these same codes and no definitive solution.

I've had the same codes ongoing for over a year now. First tuner replaced Edelbrock bypass valve, but issue continued. After that they said they couldn't find anything else.

I've personally replaced my front O2 sensor and done a smoke test for vacuum leak, both also with no luck.

Now a second tuner has been working on the vehicle over a couple weeks. First they replaced the injector control module, but issue continued. Next they tuned the vehicle (had been running Edelbrock CARB tune until now), and issue still continues. Meanwhile just hitting 60k miles so new spark plugs are going in. That's a slim possibility. They're talking about replacing the ECU next.

I am getting so frustrated with this mf car. It was so fun up until all of this crap. Somebody please help all of us get this sorted.

Have you done anything with the injectors? What injectors are you using? If they're not OEM, switch to the ID1050X for the best spray pattern