Airbox heater valve and idle speed?

Post by **luketrash** » 04 Nov 2006, 11:14

Today I am working on the car again, and I'm curious how to test to see if the air flapper valve is working in my airbox that diverts the hot air from the exhaust and switches over to cold air intake. Is there a way to test it?

Also, what is the proper idle speed in RPM for the 850 NA? Mine idles right under 1000rpm and it seems so high to me since my 960 idles at about 640rpm...

Post by **billofdurham** » 04 Nov 2006, 11:57

Remove the air cleaner assembly (airbox?).
Remove the inlet body from the housing by depressing the two tabs and pulling it free.
Check the condition of the spindle bearings, wax capsule and spring.
Place unit in the refrigerator (wife not watching) for a few minutes.
At a temperature of about 5C the flap valve should have moved to close the cold air inlet.
Remove from the refrigerator and watch as it warms up. At approx 10C it should be about mid position and at approx 15C it should have closed the warm air inlet.
If it does not work as advertised renew it.

I have never found an idle speed published but mine sits between 900 - 1000 which does not seem excessive.

Bill.

MadeInAmerica · Post by **MadeInAmerica** » 04 Nov 2006, 13:23

Mine is 950 in park

Post by **luketrash** » 04 Nov 2006, 17:01

Ok, yeah, my car is idling the same speed as yours' are. Thanks for the info.

I will check this airbox flap soon. I have a hunch that it is not closing when the engine heats up, and I'm sucking hot air into the intake at all times, which is giving me the dead powercurve feel.

Post by **kelvin6** » 04 Nov 2006, 20:16

Just ditch the thermostat. I tried to test mine and it didn't cut it, it turns out my car was just sucking in hot air nearly 100% of the time. Now that I shoved a small fuel clamp in there to push at the spring so that its stuck in the cold air position, the car runs much better. Clearly more power!

Post by **billofdurham** » 05 Nov 2006, 12:23

Just found these idle speeds whilst researching something else:

Pre-1994 models 800 rpm
1994 onwards 850rpm.

I know that my tachometer reads slightly high as I had the car hooked up to an engine analyser recently and the analyser showed 875 rpm while the car showed 950 rpm. I am happy with that.

Bill.

sixdown · Post by **sixdown** » 10 Jan 2007, 21:20

What does this mean if my engine idles at around 1600...something is apparently wrong with that..no?

Post by **MadeInJapan** » 10 Jan 2007, 21:39

Yes, you are idling way too high. Does this happen when you first start your car and then the rpm's settle down? If so, it isn't too unusual, but if it's like this all of the time I would suggest you looking at the throttle cable or spindle (it is wound around a spring loaded spindle). It could be hung up or catching somewhere. Since your ECU adjusts idle automatically, the only think I can think of that would cause this is something mechanical.

uwackme · Post by **uwackme** » 11 Jan 2007, 10:14

Also, the idleair controller could be sticking open, giving more air and raising the idle. Think of it as a baby gas pedal the computer controls. If it sticks (gummed up and needs cleaning) then its like the baby gas pedal got stuck...zooom.

steve · Post by **steve** » 11 Jan 2007, 18:39

I am having similar symptoms in that the idle flares up at start up, higher and longer than usual before settling back down to the normal range. I also had to remove the airbox Stat as it was malfunctioning. Dramatic increase in power using all cold air.

What is the proper procedure for cleaning the idle air control?? I know they must be fragile and can be wrecked by the unknowing.

Pictures would help me.

Thanks