Battery reset, then high idle, then low idle (1 Viewer)

[musthave]

Went out to the cruiser this morning, hit the key fob to unlock, notta. Unlocked, opened, no lights.

Popped the hood, found a loose terminal, as soon as I moved it a bit, the alarm went off and I knew things were OK.

Started up the cruiser, and it started idling at 2000 RPM. Throttle is fine, no other issues, but idled at 2000 RPM for almost exactly 2 minutes. Then it went down and idled at about 500 RPM, barely running, did that for two miles while driving.

Turned on after a short stop, idle is perfect, no issues.

Any idea what happened? Cold start relay?

 

[livinoffroad]

After re-connecting the batt terminal, the TPS (throttle position sensor) needs to be reset. Some folks do it running, but it's as easy as turning the key to the on position, then depressing the skinny pedal to the floor, and releasing slowly. I do it a couple times, just to make sure. Then your big fat gal is happy again, and should start normally.

 

[musthave]

I will remember that for next time, thanks

 

[ppc]

The TPS is a sensor and doesn't need to reset. The ECU gets reinitialized with loss of battery power and needs to relearn is mapping from many different sensors. The IAC - Idle Air Control is a stepper motor that controls an air bypass around the throttle plate to control idle speed. It is controlled by the ECU via a feedback system. The ECU doesn't know its position when the ECU is reset, it can only measure RPM, intake and engine temperature and send signals to the IAC to adjust the bypass volume based upon the default parameters in the ECU. Once it starts to learn/record actual data from the sensors the default parameters are overridden until battery power is disconnected from the ECU. As the learning process is underway the engine will continue to improve its performance until back to normal. The complete learning process can take a few trips to complete. A "trip" consisting of being started, run up to normal temperature, a short drive varying the throttle and shutting the engine off.