I know that in the Z6 there is a FIT Valve that is a mechanical valve that is controlled by coolant temperature (there is no ECU plug to it). When the coolant is cold the valve is open and letting air into the IM through a hole in the TB before the throttle plate. This essentially creates a small vacuum leak which in turn lets the motor idle higher than normal. As the coolant warms up the valve closes and no longer lets air in through the hole in the throttle body.

the D16Y8(96 up civics) do not have such a valve.

WHAT CONTROLS THE WARM UP IDLE IS THE EKs???

 

the EACV, which most hondas have regardless of having FITV or not.

 

that is also known as the AICV. this controls the air supply electronically through the ECU. re you sure that this also controls the higher warm up idle the settles after the car is warmed up?

 

yes

 

OK. my problem is that My idle is too low when the car is cold. I have to hold the gas for the car not to turn off. After it warms up, it idles fine, but If I turn on the AC, it droppes very low again. is this valve responsible for this?

if not, any other IDEAS?

thanks for all your help

 

Is it a 99-00 Ex? How many miles?

 

96 EX with 129K miles

 

96 EX with 129,000 miles

 

Then just your IACV (idle air control valve) is responsible. On 99-00 Ex's, they introduced a similar system like the FITV, but it wasn't mounted on the throttle body like a traditional FITV is. It was installed in the thermostat housing.

Get the engine warm and use some throttle body cleaner to shoot into the IACV while using the throttle to keep the engine alive, is what I'd try first.

Have you done a tune-up lately? Plugs, wires, cap, rotor, air filter, fuel fitler, PCV valve, valve lash, O2 sensor (especially if the original has 129k), sand your ground cables, etc...

Hopefully you have NOT touched the idle screw to cure this problem...

 

thanks for the troubleshooting list. the tune up is next after I try the TB cleaner. I have not touched the throttle screw

 

why is it a bad idea to touch the idle scew??

 

Another thing you can try to properly "daignos" the FIT valve is this. On a Y8, there is a small hose that comes from the valve (on top of t-stat housing as prev. stated) to the middle of the valve cover/intake manifold area. The other hose off of the valve goes into your intake tube.

When it is cold and the car is idling, you can "pinch" than line tight with your hands. The idle should drop. If it don't, there could be a restriction in the line, or the valve is stuck in the closed position.

Oh, and the valve is plastic, and they break REAL easy, just FYI from someone who may know a guy who might have broke one

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">why is it a bad idea to touch the idle scew?? </TD></TR></TABLE>

Because everything is calibrated properly from the factory. If it's not working right, something may need cleaned (like the efcrhis was saying) or something else is not working properly or malfunctioning.

If you play with the "minimun air" setting (idle screw) your just going to make diagnosing it and getting it right worse. Don't touch it.

 

thank you sir. makes very much sense. I have not touched it and will not.