Hello,
first of all sorry for my English - I hope I will explain properly what I mean.

My Engine is D16Y7 and for a long of time i've got this problem. All gaskets which I've replaced on the throttle body and manifold are new brand OEM Honda. TPS are callibrated like manual says (0.48v close, 4.50 open), but still after pushing clutch when I driving the RPMs are fall down to 800 RPM correctly, after that very quickly growing to 1200 RPM ( I have no idea why ), this same situation after push and release gas pedal when car is at a standstill. I found a video where you can see same situation like mine (5 sec): youtube.com/watch?v=twBp_3QH4m4

What could be the reason? I hope you can help me.

 

With an idle problem, step 1 is always bleed the cooling system. It takes a long time, and I recommend the spill-free funnel set shown in the video.

https://www.youtube.com/watch?v=zUpXgAJ1gjU

 

I read somewhere that my engine cooling system bleeds automatically - there arent bleeder valve in my engine. Really it may be a fault ?

 

It does bleed itself somewhat, but it's easy for air to get continuously circulated because the water pump chops the bubbles up very small.

The bleed port is not really for bleeding, it's only used when initially filling the system. Modern Hondas don't have them. You still need to run the motor for several fan cycles as shown to get the bubbles out. Revving the engine, squeezing the hoses, and switching the heater temp from hot to cold every few minutes all help to release trapped air. If you get that funnel, you will spend a good 30-40 minutes doing this process. Engine has to get to full temp for the thermostat to open. You will know the coolant reached max temp when the radiator fan comes on. For my CRX, the fan had to cycle on & off twice before no more tiny bubbles came out of the funnel. Then cap the radiator once the fan switches off for the third time. Let it continue running to get all the air out of reservoir hose.

 

Read this thread

https://honda-tech.com/forums/honda-...-help-3290197/

 

I've got another type of IDLE, changing to another - no improvement.

I don't think there were still some air bubbles in the cooling system - riding already half a year.
Another what I checked that unplugging TPS sensor fixes RPMs problem, so I changed throttle to another one - same problem (not wine by TPS, callibrated and cheched values - are OK)

// EDIT:
I don't understand why (if it was), the air in the cooling system could affect on the engine RPM? Any explanation?

 

Any help ?

 

I'm currently having a similar problem with my B18C1.

From what I understand, air in the coolant system may affect your FITV (Fast Idle Throttle Valve). The valve has a wax plug in it that expands when the coolant temperature heats it up. The expansion plugs a bypass on your throttle body that allows air to bypass the throttle plate during cold start. The extra air increases RPM. If there's air in your coolant, the FITV might not being heating up enough to plug the bypass.

Do you have the service manual? There's a page in the service manual (at least there is for the integra engines) that ranks the possible causes for a high idle from most likely to least likely and lists steps to fix them.

 

Ohm test your engine coolant temperature sensor. Could be out of spec making the ECU think the engine is not warmed up, thus it runs at fast idle. This sensor is also why a bubble in the coolant makes the speed vary. It can't get a good reading if there is air present. The importance of bleeding the cooling system properly is, well, very important.

Make sure throttle cable is slack and throttle plate fully closed when no one is pressing the gas pedal.

If you take the air filter box off, you will see there are holes in the side of the throttle body before the throttle plate. These let air into the engine for idling purposes. You can see which one is letting the excess air into the engine by blocking them with your fingers. You should be able to stall the engine out by blocking all three. If not, there is an air leak somewhere.

 

Thanks for reply!

Throttle cable is slack and throttle plate fully closed - checked many many times. I've bleeding the cooling system two times - no results :C
Another bad "think" what I found that scrawed IDLE adjusting screw does not affect on the RPM (in my opinion should be low, but still are 850 rpm)

I was left to check engine coolant temperature sensor - I would like that it was his fault.

 

put in a new water pump and bleeding is driving me nuts.
funnel arrives tomorrow, lots of reviews say it's the answer:

https://www.amazon.com/Lisle-24680-S...ll-Free+Funnel

fingers crossed...

 

I'm convinced that bleeding cooling system doesn't make an effect. Any ideas ?

 

spent 90 minutes today with the new funnel.
making progress but it takes hours apparently.
i think colder temps also slow down the process.
revving the sh^t out of it also helps the bucking bronco syndrome. 8(

https://www.youtube.com/watch?v=zUpXgAJ1gjU

 

Have you checked the idle air control valve?