fast idle ?

[ACCORD EX]

hello everybody !
i need help !!!!!!!!!!!!!

my car goes into fast idle normally at morning !( choke closed , idle at 3000 rpm ) and it"s 23 'c !
that's not the problem !
the problem is when i leave the car for say 3 hours in shade ( not hot place ) the car goes another time in fast idle ( idle at 3000 rpm and CHOKE IS OPENED )
i tried to lower fast idle but i unscrewed the screw as much as possible and was only able to lower it to bit under 3000 rpm !

how can enable fast idle when car is only cold ( choke is closed )
i think the problem now is in Throttle while teh choke is already opened but the car goes to fast idle ! ??????

so what controls the fast idle throttle unloader ! and how can i lower it more ????? i have an A20A2 engine !
picture of teh diagram is attached !

pleeeeeeeeeease help!

Mike

[shepherd79]

it is hard to tell why it does. my car did the same thing. I just taped on the gas pedal and it would drop the RPM right away.
you can splice the switch to the choke wire and use the switch to control the choke.

[ACCORD EX]

it doesn't go down with me when i tap the gas ! the problem is in the fast unloader not in the choke !! because the choke is opened when it does it the second time!

[jb2wheels]

My 87 was doing this as well but would not kick down even after tapping the gas. The problem was the idle controller on the passenger (RH) side front of the carb. It would idle at 3K all the time.
It's gone now and the vacuum line capped. Idles at 750 every time now.
One less vacuum line to worry about

[ACCORD EX]

well this is not a solution ! it's a short cut !!!! hehehhe !
but thanx anyway !!

i would like to know where is the solonoid controlling the fast idle ! ??

[jb2wheels]

Nope - it's a solution! It's the vacuum diaghprhagm hose #18 connects to. When the thing no longer holds a vac, it holds the engine idle sky high.
It's only purpose is to keep the "idle" up between shifts and such to reduce emissions. Take it off and put it in the trash, then cap off the line at the hard line.

The fast idle unloader is on the back, RH side of the carb ( I think). The factory manual has easy troubleshooting steps for this peice. Follow them and you'll know what's wrong.

[ACCORD EX]

well i asked my brother to start the car for me ! so i can observe all movements in teh carb !
i noticed that choke is closed then it opens ! but idle still high 3K and then 2 minutes later the idle goes down ! another thing the FAST IDLE SCREW is all the way out and when i screw it in it gave me higher fast idle ( higher than 3k )

my conlcusion is that something keeping the idle high without touching teh throttle cables or this whole mechanism !!! how can this happen ??? i observed very accurately and not a single thing moved !
is it cold timing advance or what ? and can it go to 3000 rpm and then goes back down ! ?

pleeeeeease help guys !

Mike !

[ACCORD EX]

i disconnected the lines from the advance diaphram on the distributer and it lowered it a bit ( 200 rpm ) !
so what is giving the damn gas to the carb heeeeeeeeeeeelp !

Mike !

[DanG86LX]

Fast Idle Cam holds the throttle slightly open during startup:
http://www.ualberta.ca/~dg5/Honda/Fuel/11/FIU-cam1.JPG
A - Fast Idle Cam (FIC), with 4 steps, say 4th the highest idle
B - Lever pushing the throttle

Set a vacuum gauge on #18, should be vacuum there seconds after startup, provided the thermovalve is shut(doesn't air bleed).
Then Fast Idle Unloader (FIU) should release FIC from 4th to 2nd.
Then when coolant gets > 55*C, #19 gets vacuum to FIU which releases FIC from 2nd to 1st.
Then when the choke flap is about 45*, it pulls FIC all the way and the throttle sits on Idle Stop Screw..800rpm.

[A20A1]

I got your PM... I don't have much to add.

Your powervalve isn't stuck is it?
Or possible you have low vacuum because of too much throttle and distributor advance to maintain the idle. I've seen a few Accords tuned that way.

[ACCORD EX]

i disconnected the vacuum lines to the fast idle unloader ! and plugged them and it still goes to 2750 instead of 3000 rpm !

the weird thing is !> it behaves exactly liek fast idle ! goes up to 3000 rpm , hangs for 3-4 min and then goes smoothly down to idle !

what can cause this other than fast idle unloader , distributer advance , throttle controller , AC booster ??????


thanx a lot guys for all teh replies !?

[DanG86LX]

When @ high idle ~3k, if u pull the choke linkage till choke is vertical, then tap the throttle, does it go to normal 800rpm idle?

[ACCORD EX]

i tried it now ! it waits 2 minutes after teh choke is vertical and i can't do anything till it comes down by itself and very smoothley !
iam really confused it 's so weird

Mike !

[DanG86LX]

..but at least u should be able to see if that throttle lever rests on High Idle Cam (FIC) when 3k, as in picture above. That might exonerate FIC. Use a flashlight and look from choke heater side. If it does, then FIC is stuck there (it should follow the opening choke flap). Dump a can of carb cleaner right behind the choke housing where the choke linkage, levers and springs are. Proly when the 2nd stage of Fast Idle Unloader kicks in (vacuum on outer prong, #8 on ur diagram i believe) is when 3K -> 800.

[ACCORD EX]

i cjecked today another time !
the fast idle cam doesn't move a bit and doesn't even touch throttle mechanism !
but may be it's only me , i'll dump some carb cleaner anyway !

Mike !

[DanG86LX]

:werd: indeed!

When @ 3k, have u tried pushing the throttle with ur finger back to idle position?
BTW when 3K -> 800 does the throttle move at all, i.e. keep ur finger on it, it should move back ~ 2..3mm.
What else, u already disable A/C booster and TC. What about disabling secondary and also most important - big slack on the throttle cable.

[ACCORD EX]

i'll try this finger trick !
i noticed that the secondry sprays gas when it idles fast !
i'll disable it and try it again !

thanx a lot for all the help !
i really appreciate it ! :)

Mike !

[ACCORD EX]

woooooooohooooooooo ! i found out the problem but not the solution !
it's the secondry causing high idle ! i disconnected line 28 and plugged the open lines and the idle gone immediately down !!

my question now is why does the vacuum secondry needs vacuum line 28 from the thermovalve ???? should it help in fast idle ??

thana a lot guys !

Mike !

[jb2wheels]

This is how the secondaries "should" work - 2 parts - mechanical and vacuum.

The vacuum secondary gets its vacuum from the port on the carb about 4 inches away. The line has a T in it. The thermovavle is open when it's cold to bleed vacuum so the secondary won't open on a cold engine. Once the engine warms up, the thermovalve closes, the vacuum is no longer bled off, and the secondaries can open.


If you're secondaries are opening at idle, you have a mechanical linkage problem - maybe a bad return spring on the secondaries?

[ACCORD EX]

so my vacuum secondry opens automatically on cold and then closes when hot ! and then it opens normal with throttle response ?? how can this be ??
that means that line 17 brings vacuum to thermovalve A on cooler pipe !
why is line 17 connected to 2 thermo valves on the intake manifold ! ??

thanx a lot man !!! !really appreciate it ! ?

Mike !

[jb2wheels]

Gonna have to open my hood and my book to see what's up - other than removing the throttle controller, my hoses are very stock.

In theory, you should be able to directly connect the vac secondary to the carb - just bypass/cap the T fitting. Would be interesting to see how it works.

[ACCORD EX]

well here is my scenario !
i have no connection to the air box other than PCV hose and #8 line ! NO # 17 ! so i think someone messed wit my car before and connected the # 17 lines for the 2 thermo valves behind the carb directly to the # 17 hose going to thermovalve A on the water tube in front of the distributer ! without connecting it to T fitting that should connect to the airbox ! that's why i get vacuum in line 17 in thermo valve A !! and this vacuum causes teh secondry to open when cold and closes when hot automotically because it's conected to line 28 through this Thermovalve A !! ??

i'll check it out tomorow !

thanx a lot for all the help!

Mike!

[A20A1]

Originally posted by jb2wheels
Gonna have to open my hood and my book to see what's up - other than removing the throttle controller, my hoses are very stock.

In theory, you should be able to directly connect the vac secondary to the carb - just bypass/cap the T fitting. Would be interesting to see how it works.

Yeah that is part of the process of the vacuum line removal... it works fine and is much more responsive, for a vaccum connection.

and then there is always the option of the mechanical secondary conversion...

I hope you fix your carb soon Mike... I'm happy I could help... I should save my IM's next time and cut and past it to the board just for others to read later on.

[DanG86LX]

Mike (ACCORD EX), every 3g vac-diagram seen has secondary routed the same:
http://www.ualberta.ca/~dg5/Honda/Fuel/11/8b.gif
Vacuum comes from ports @ venturi level from both primary and secondary.
#17 is an air bleed line and does go to several t-valves including the ones @ manifold, never should be vacuum in it.
Some ppl (including myself :D ) removed #28 and capped at small T.

[ACCORD EX]

woooooooooohoooooooooo i fixed my problem ! it was exactly as i described above ! now my fast idle kicks in and i adjusted it to 2000 rpm ! my problem now it doesn't go down till i tap the gas ! so i am going to clean teh fast idle unloader tomorow !

thanx a lot guys !!!!!!! :)


Mike!