Thread: Low Stumbling/hunting idle thread (Auxilary Bypass Valve). Was Coolant Temp thread.

Yep Ian.. I think your Air Regulator fine..

Air Regular Operation sequence...

The Air Regulator unit is like a backwards thermostat, as it closes with the presence of heat. Then it slowly reopens when completely cold again. Secondly, the Air Regulator is only used by the ECU with a completely cold engine.

- So when you start a cold engine, the engine is cold and the Air Regulator is open (due to lack of heat). This allows extra air into the intake and the idle increases which is desired with a cold engine.
- After starting, the ECU sends power to the Air Regulator. If the RPM increases, it will continue providing power to the Air Regulator for 90 seconds. This powers the Air Regulator circuit which heats the valve causing it to close slowly over 90 seconds. The idle is also being regulated by the ECU using the AAC value whenever the engine is running.
- Second scenerio, engine started and the RPM does NOT increase (Air Regulator is closed). ECU still sends power to the Air Regulator but only for 5 seconds which causes the Air Regular to heat up and completely close if its only open a small sliver... Thus with a warm engine, the Air Regulator is not used. All warm/hot engine idling is controlled by ECU using only the AAC valve.

Bad Air Regulator symptoms:
- If stuck open, you have unmetered air going to the intake always and the ECU cant adjust the idle down using the AAC; giving you a high idle always.
- If stuck closed (like both of ours cars), you dont have enough air during startup, the idle stumbles & chokes, and finally engine dies suddenly.

When I tested my unit, I put the unit in the freezer for an hour or so. The strip opens from the cold. Then, I added power to the terminals using a 9-volt square radio battery. This closed the Air Regular strip after about 45 seconds. It stays shut but will completely open again if I put it in the freezer again for an hour or so...

Your Air Regular maybe sticking a little bit but I doubt it.

To Clean the unit:
- Spray Throttle body cleaner on the closed strip and let dry.
- Freeze it for a couple of hours until its open completely. (but dont lay this filthy unit on your frozen food )
- Remove from freezer and Clean it throughly with Throttle body cleaner. Apply 9-volt radio battery power and spray the crap out of it as the door closes..
This process will remove all of the oily residue and will insure smooth operation.
(Remember, you can activate any 12 volt circuit with a 9-volt radio battery, to safely test it without the fear of damaging the unit; this includes all relays, switches, solenoids, etc.)

Hopefully, you didnt damage the valve strip by forcing it open with a screwdriver..
The coil spring is heat actived and not spring activated.. Damn Ian.. eek....

Why did you only test term B for olm on the Air Regulator? The Air Regulator ohm test is using both terminals seeking a good ohm value of 70-80 ohms.. This is why I think your unit is fine: 71 ohms.

got a long 3/4 socket for a 3/8 ratchet and a part of the intake doesn't let it in.... i might have to take down the whole damn intake thing!!!

From the Autozone site:

Quick question. Is there really a difference in the Automatic Transmission Auxilary Bypass Valve and a Manual Transmission Bypass valve? Reason I ask is my JDM motor was an Automatic. I swapped flywheels and made it to work with a 5 speed (like most of us). There is a listing for both. Whats the difference? If there is a difference, I have on for an automatic on the car.

I will check the FAST for differences.

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UPDATE: Checked the FAST.. Amazingly, 2 are listed:
One for 5-speed 22660-93L00 and One for automatic 22660-53J00.
Someone should call GregV to see if differences exists
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As for your the Autozone instructions (why dont u use the NX FSM sent),
its testing for continuity with ground and not voltage.
But we know your harness is good and the Air Regulator's internal circuit is fine..
So, you should be okay there..

How is your car startup now??

If this is a highport motor just get 2 3/8's long extensions with a 10mm socket at the end and unscrew the bolts that hold it to the intake.

It starts a lot better now. It will fire right up and hold idle for a minute, then stumble down for like 7 seconds, then go right back up to regular idle. I know for a fact that this was the culprit now. It probally needs another shot of cleaning or maybe a new ebay (pricewise they are only $50.00 on ebay). But it will do for now knowing that I found out what it is and fixed a couple of other things along the way.

Great... Just blast it again with Throttle Body cleaner.

Check with robchaos or Keo for new OEM parts.
They maybe able to get OEM for same price as ebay.. Worth a try!

Got a new valve and it completely cured my idle problem. I reccommend Rockauto. Bought an Airtex and lo and behold it was a Nissan OEM part inside the box.

Got a new valve and it completely cured my idle problem. I reccommend Rockauto. Bought an Airtex and lo and behold it was a Nissan OEM part inside the box.