Major Idle Issues!

[always240SX]

I have a 96 240SX SE and my sensors have all been recoded, thermostat replaced,and throttle body/IAC Motor cleaned. The problem is that when the car is on whether I am stopped at a light or driving high or low speeds, the idle seems to do it's own thing. The car drives great and the engine isn't racing or anything, the idle will just stay on zero, flucuate inbetween 1.5 - 3, or will slowly move up and then right around 5(a little befor redline) I will pull over and turn the car off. Then it goes back down, but continues to do the same process. Is it just the gauge that needs to be replaced or what??? I have spent too much money already in trying to fix this - please help!

[West]

The problem is more then likely your AIV (Air Intake Valve)

You AIV is the box located just in front and slightly to the right of your intake box. You should see a tube that connects your intake box to the AIV.

For Diagnostic purposes I would suggest first removing the pipe that connects the intake to the AIV and then start you car to see if it still has a idle problem. If it has changed in its idling behavior then its more then likely your AIV. If it is proceed to the cleaning process below.

The AIV is easy to do. Just take a real hard look at it and find the 4 screws that hold the 2 halves together. Remove the small vacuum line to the top, the larger one, and take the 4- screws off. Pull the top half off and there is a "cap" over the reeds. GENTLY pry the assembly out of the housing. There are 2-sets of reeds. We only did one at a time so we could see how they went back together. Clean this out with a wire brush and a can of carb cleaner. Reassemble and your Idle should be fixed.

[daywalker]

i had almost the same problem and changed everything, but my car would die sometimes. as it turnes out it was my distributor. water got in it and killed it. also make sure ur battery is doin fine

[sixthgear]

Hrm, I had this problem on another car.  It could be that the detonation timing is off, causing premature detonation and delayed detonation.  This usually occurs from spark plugs and spark plug wires.  It would be good to check them every so often, say every 10K miles, to see that they are still looking like metal.  I hope this helps, it may seem odd but sometimes it fixes it without costing a pretty penny.

Signed,
6

[diabolic hippo]

i had the same symtom to, when at a stop the idle will go really low and die out, i replaced cap, rotor, plugs, fuel filter, checked for vaccum leaks. it turned out to be the EGR valve, replaced it now it runs great.

[TwoFourO]

In reference to the reply above...Where is the EGR valve located, and what does EGR stand for.  Would appreciate the help very much, thanks.

[Anubis]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (WeST @ Mar. 11 2002,1:03)</td></tr><tr><td id="QUOTE">You AIV is the box located just in front and slightly to the right of your intake box. You should see a tube that connects your intake box to the AIV.</td></tr></table><span id='postcolor'>
This box does not exist on S14 models to my knowledge. I belive the AIV for S14's is located to the left behind the intake manifold a couple inches from the firewall. There are two metal pieces with a hose running between them. This may have something to do with the idle problem. I have a 95 and I experience a rough idle at certain times.

[willcheung]

EGR stands for exhaust gas recircuilation valve locate on the exhaust monifold. The purpose of EGR valve is an emission componet require to reduce NOx emission. When the engine combustion chamber temperature reach above 2500 F degree, it create NOx and is a pollutant that make smog. EGR valve job is to recircuilate exhaust gas back in to the intake monifold and use it to cool down the combustion chamber temperature. EGR valve are control by vaccum, solenoid, or temp sensor