I recently had my BMW E30 (RHD, individual throttle bodies) on the dyno for a tune. The car runs great under load, but the tuner couldn’t get the cold start idle working. On the dyno, warm idle was rock-solid and he advised that closed-loop idle control was enabled (Idle Control Active + PID Control both on).
The next day, on a cold start, it constantly stalled — barely drivable.
Steps I’ve Taken:
• Checked logs — Idle Control Active never comes on at any point (even warm).
• Verified TPS = 0% at closed throttle.
• Bought a brand-new Bosch 2-pin PWM IACV — no change.
• Tried “Reverse” setting for idle valve — no change. Haven’t swapped pins yet (could this be the issue? Is there risk trying that?
• Output test makes valve click, but I can’t tell from sound alone if duty % is increasing or decreasing airflow.
• Idle valve DC changes slightly in logs but PID DC correction stays at 0%.
• When AC is turned on, engine just dies (no idle-up).
• Before the tune, I could see Idle Control Active (green light) in EMU Black v2 software — now it never engages.
• Created a log from cold start → idle (low, ~830 RPM, target is 1000) → pressed AC button (just to see reaction).
The Problem:
Idle control never engages in any condition (cold or warm), and A/C activation stalls the engine. Idle DC seems to follow base table but never goes closed-loop. I’m looking for advice on what conditions could be blocking idle activation, and where to check next in EMU Black settings.
20250809_1341.emublog (31.8 KB)