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Fast Idle Thermo Valve

I've been driving an automatic 1990 Honda Civic DX for 2 and a half years. The Car has been great, but always idles really high before it is warmed up. Especially if not used for a couple of days. I realized that it will idle higher than normal when cold, but this is really high, and I have to keep my foot on the brake pedal or it will take off on me until warmed up. Through reading forums and and other internet sources I have reason to believe it may be the Fast Idle Thermo Valve. I realize there are other possibilities! I have seen a write up on other forums with pictures, and they show how to screw in some kind of plunger in said FITV. The problem is that the pictures show an Integra engine bay, not a Honda Civic. Apparently the FITV loosens up over time. I have the Haynes manual, and have looked under the hood for the FITV, but cannot find the damn thing! I am not a mechanic, and have only done basics like 02 sensor, Cap, rotor, ignition coil and spark plugs, etc. Does anyone have a link with a picture, or a diagram or description for this year(1990) Honda Civic in regards to the FITV? Thanks.

Reply to
Rubntugdug
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presumably an automatic.

any idea what the revs are? [you can buy an instrument cluster from a junkyard, with tach, for about $40 these days.]

higher revs are normal - ~1500. and at that speed, the torque converter will pull quite strongly. are your brakes good?

that's 99% of your problem right there.

first stop is tegger.com for the faq's and links to factory workshop manual downloads.

next step is check all your hose connections, then test fast idle and iac valve operation per the manual.

Reply to
jim beam

Reply to
Rubntugdug

Unless the idle speed will not come back down after warm up, then i'd suggest you leave the FITV as is, it serves a purpose.

When engine temp is cold, the valve opens to allow more air to enter the intake manifold (behind the throttle plate) to increase idle speed and reduces warm-up time. It utilises a form of controlled vacumm leak, similar to that of the PCV valve

And also by allowing more air to enter, it helps offset the harmful effects of the rich mixture caused by the IAT sensor during the warm up period.

Now you just want to drive right away, of cource you can shut the damn valve closed permanently by doing such modification so that the transmission and the brakes are not subjected to too much unnecessary stresses.

But why would you want to put your engine under load, any load, when it's still cold?

The warm-up period is the nastiest condition that an internal combustion engine has to endure. Uneven distribution of lubricant, concentration of heat, wet mixture, low fuel burning efficiency, off valve timing... blah blah... and God created the FITV

Reply to
bi241

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