Ea-82 idling SLOW

[dklink2000]

So my 92 Loyale with a EA-82 tbi is idling really slow. It hovers right around 400rpm. The thing is it only does this when warm and when in gear (3 sp auto). I noticed a couple of days ago, the voltage meter acting crazy. Shooting up to 17 amps, then down to 8 or so. Could the drop in idle be due to a shot voltage regulator? I was planning on dropping in a new alternator this weekend and was wondering if I should do anything else while I had the car torn apart.

[dklink2000]

Anyone??

[Skip]

DK

There may be a connection but you do not allude to whether the two event coincide.

This statement is a bit nebulous

"the voltage meter acting crazy. Shooting up to 17 amps, then down to 8 or so."

I will assume you mean volts not amps as your voltmeter reads volts not amps.

At any rate it sure sounds like the alternators internal voltage regulator is toast.

Please examine all battery connections for poor contact, as an alternator running without a battery load can fail in this manor.

Rest assured, this is a pretty common problem with this series. A new alt should return you to normal.

Subaru must have known this might happen and has protected the brain (ECU) from these voltages.

On the idle problem the idle is controlled by a controlled vacuum leak, the screw to adjust this "leak" is located

in a recess on the throttle body, but the IAC may be wanting attention please read this previous post I made on the subject

Dave, on the very front of the throttle body is a "can" shaped electrical devise that sits horizontal.

This, for future reference is the IAC valve (Idle Air Control valve).

Look on the passenger side of the throttle body just behind the can. In a recess sits a screw that also runs horizontal. This is the idle control.

 

The way the idle is controlled on fuel injected cars (turbos also) is to allow a small controlled vacuum leak. Not by adjusting how far the throttle plate is open as is the case on a carbed car.

This is mentioned for the sole reason that turning the screw anticlockwise raises the amount of the vacuum leak and thus increases the idle. (On a carbed car turning the idle speed adj screw this way lowers the idle)

 

Hope this helps, as you are correct- during the winter months, a slightly higher idle speed helps offset the battery drain caused by the heater blower, headlights and wipers all being used simultaneously at some times.

 

Note: the IAC valve controls the idle speed during warm up, but can affect the idle at all times if the internal shuttle sticks.