fast idle thermo valve

[sulimed]

who has theirs blocked off.

do you like it?
what did it do for your performance?

[d112crzy]

it does nothing for performance.

Mine isn't blocked off, I only bypassed it.

When I put it in neutral as I'm coming to a stop, the idle jumps to about 2k then drops to about 300rpm, almost killing the engine then goes up to 750rpm.

it's annoying as fuck. I'm gona hook the coolant lines back up.

[prNonVtec4u]

blocked it off and bypassed the coolant lines...

pretty glad i got rid of it, one less thing to go wrong(which is what it's known for) and the car idles perfectly... IACV still takes car of cold starts by keeping rpms higher when cold/normal when operating temperature

[d112crzy]

Interesting. Maybe I have a different problem.

Not sure what it could be, because it only does this when coming to a stop. Idles perfect besides that.

[prNonVtec4u]

same thing happens to me EVERY time i run a chipped ECU

problem goes away w/ stock ecus

[NAiL05]

it does nothing for performance.

Mine isn't blocked off, I only bypassed it.

When I put it in neutral as I'm coming to a stop, the idle jumps to about 2k then drops to about 300rpm, almost killing the engine then goes up to 750rpm.

it's annoying as fuck. I'm gona hook the coolant lines back up.

I think thats how wafflefries has it on his car. He runs the stock p13. The wierd thing is that it does it sometimes and sometimes it doesnt. Wierd. Rebleed maybe dunno. I always thought if you bypassed it and drained out all the air it would work just fine since its mostly just cold idle start.

[johnl]

Mine is blanked off with a brass shim 'blanking plate' between the FITV and the plenum. No air can pass into or out of the FITV under any circumstance.

Simply bypassing the coolant to the FITV may not have much affect, I did this on mine and it made no perceptible difference to cold or hot idle speeds (and I did have a high cold idle, though this may have been the IACV kicking in). I suspect that the FITV picks up enough heat through heat soak from the plenum and ambient engine bay temp to operate satisfactorily.

d12crzy,
If the FITV is causing your idle problem then I doubt bypassing the coolant will affect your problem, which is more likely due to the FITV being out of adjustment or leaking internally. I suggest you blank off the air flow between the plenum and FITV. I wouldn't rule out the IACV as the cause of your idling problem either...

Blanking off the FITV does absolutely nothing for performance good or bad, simply avoids a source of potential trouble. If you do this you won't get a cold high idle from the FITV, but that's no tragedy, and the IACV will step in to do this to some degree in any case (or should do).

However, I also have the IACV blanked off in a similar manner. Rather than writing all this up again (to do with blanking off the IACV), I'm pasting something I recently posted on another Honda site:

If you disconnect the IACV electrical connector you'll get a CEL, and the on/off throttle behaviour will become harsh as the injectors cut in and out. However, there's no need to disconnect the IACV and fit any sort of resistor to avoid these problems associated with disconnecting the IACV electrical connector.

Some time ago I placed a restrictor plate between the IACV and the plenum chamber to reduce the unwanted affects of the IACV that occur when shifting gears (i.e. keeping the rpm high between shifts, and not allowing the RPM to drop fast enough when it stops holding the RPM high, among other things).

This addressed the problem to some degree, but not enough. I've since blanked off the IACV ports completely (with thin brass shim like a 'blind' gasket) so that no matter what the ECU tells the IACV to do, the IACV has no affect. The IACV still obeys the ECU (futilely opening and closing), and the ECU doesn't detect that it's not working (so no CEL or other misbehaviour associated with the ECU), but no matter what the IACV actually does it cannot affect airflow into the plenum under any circumstance.

To my surprise blanking off the IACV airflow doesn't adversely affect on/off throttle behaviour as disconnecting the connector does. Before I fitted the blanking plate I expected it probably would affect on/off throttle behavoiur and that I'd most likely have to delete the experimental blanking plate because of this.

I was originally assuming (strongly suspecting) that blanking the IACV airflow would affect what the MAP sensor was telling the ECU and that this would be what affected on/off throttle behaviour (as with the electrical connector disconnected), but this appears not to be the case. The harsh on/off throttle behaviour caused by disconnecting the IACV seems to be a result of the ECU doing something strange because it's detecting that the IACV isn't working (which it doesn't do if the connector is still connected).

If you blank off the IACV, I'd strongly reccomend resetting the ECU.

There are downsides to blanking off the IACV airflow. When cold (and with the FITV also disabled) the idle will be very low, but it's easy to deal with and doesn't last long.

The IACV can no longer adjust idle speed when auxiliary loads are placed on the engine (air con etc), but if you adjust base idle (which becomes THE idle with the IACV blanked off) on the high side of the spec range then the idle rpm drop when the AC etc is used isn't too bad. I found that fitting new spark plugs eliminated a lot of low idle speed vibration with the AC etc in operation. The engine does vibrate at idle more with the IACV air flow blanked off and the AC working, but it's not much and well worth the benefits.

So what are the benefits? The rpm drop much more satisfactorily when shifting up to the next gear, giving a faster and smoother shift. 'Rev matching' on downshifts is easier / more accurate because the engines reaction to 'blipping' the throttle is much more predictable.

On my car I gained much better low rpm and light throttle torque (not a result of fitting the new plugs, this was apparent before I fitted the new plugs). I now don't need to be nearly so careful to balance throttle and clutch slip taking off from rest (which used to be a bit tricky due to poor low rpm torque threatening engine stall and / or just makng the take off less than perfectly smooth), and hills that used to require a largish throttle opening and / or a downshift can now be taken with ease on a much lighter throttle and / or in a higher gear. This makes no difference to flat out performance, but overall the car is much more pleasant to drive, and I expect an improvement in mpg (though I haven't yet checked this).

Car is a CB7 Accord by the way.

[sulimed]

thanx u sir

[NAiL05]

Hmm blocking the passages to the FITV is a good idea. I never thought of that. Shouldnt be hard making a plate for that lil opening. Gonna have to try that sometime.

[d112crzy]

I'll try blocking the passages today. Think just blocking the inlet/outlets of the FITV would work?

[NAiL05]

I'll try blocking the passages today. Think just blocking the inlet/outlets of the FITV would work?

Do it and you shall find out! But that would be the only place i can think of to block off.

[cp[mike]]

i dont think the FITV ever gets fully closed, even when hot... that gap is adjustable by turning the outer plastic ring underneath the cover. simply bypassing the coolant disables its functionality, but would not correct the problem of the valve being adjusted too far open.... which is usually the problem for most people, it slowly works itself more and more open from age/vibration. blocking the air passages is the only effective way to disable it... be it just by adding a blocking spacer, or by removing the valve entirely and looping the lines, which is just a little more work, though its not very hard to cut a square out of thin metal, drill 2 holes for screws, and silicone the sucker on. personally im not running one whatsoever.

[johnl]

I'll try blocking the passages today. Think just blocking the inlet/outlets of the FITV would work?

That's what I'm saying. I wouldn't try blocking the ports themselves (by filling the holes with something or other). All you need is some shim (drink can aluminium would do fine) between the plenum and the FITV.

You can leave the coolant lines connected or not, makes no difference if the airflow is blocked (seems to make no difference in any case whether the airflow is blocked or not, at least on my car).

[d112crzy]

Well, I put a hose between the outlet/inlet and it seemed to make a big difference.

I didn't drive it over 20 feet mind you, but it would always idle high in neutral while coming to a stop. It didn't do it after the hose.

I'll try using some soda can aluminum to block it off later and see if it makes any difference.

[NAiL05]

Cerveza dance time.