I've searched, haven't found any straight answers.

99 Si JDM B16 block, mugen headgasket, skunk2 valvetrain, stock cams, VAFC.

Problem started 2 nights ago after changing my oil then doing some VTEC runs. Revs started to bounce from 900-1800rpm.

Wiped my IACV down and that helped it a little. For the next day the revs went from 1100-1300 and would eventually idle smoothly at 1000, which is still too high.

Today I removed my throttle body, IACV, intake manifold and sprayed them down with carb cleaner. Put in some new NGK copper plugs. Now the revs are back to bouncing from 1300-2000 violently.

Attempted to check the CEL (it's been on since i bought the car, assuming it was from my gutted cat/missing O2 sensor), but no dice. The wires to the ECU are spliced all weird from the VAFC (prev owner).

This stuff may be unrelated... did a compression test: 150 270 180 300+ (off the gauge). I was using SeaFoam carb cleaner. I found one small tear in one of the coolant hoses connected to the throttle body, but I doubt there's a leak there.

how messed up is my car? anyone out there know how to fix it?


Modified by ziich2 at 9:41 PM 9/8/2005

 

Someone suggested it's the FITV... but I can't find it.

 

bump because i want to know

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by spoonspeed &raquo;</TD></TR><TR><TD CLASS="quote">bump because i want to know</TD></TR></TABLE>

Same here

 

theres 2 holes in the throttle body. use your finger to cover one of them up while the car is running. then if the idle stops bouncing when you cover one of the holes then that is your problem. i believe the iacv is the top hole and the fitv is the bottom.

 

if youve checked the iacv and the fitv and cleaned both of them then check you throttle body gasket for any cracks/leaks.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ziich2 &raquo;</TD></TR><TR><TD CLASS="quote">Someone suggested it's the FITV... but I can't find it.

</TD></TR></TABLE>

There's only one hole. When i cover that up it starts idling at 800 which is normal enough for me.

ok? so now what? exactly what does that mean and what do I need to do to fix it?

Does my VAFC control my idle at all?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ziich2 &raquo;</TD></TR><TR><TD CLASS="quote">

There's only one hole. When i cover that up it starts idling at 800 which is normal enough for me.

ok? so now what? exactly what does that mean and what do I need to do to fix it?

Does my VAFC control my idle at all?</TD></TR></TABLE>

did you check the throttle body gasket?

 

it could be the map sensor on the backside of the throttle body, i had a b16 in a rex and it used to do it all the time. a buddy of mine at a shop unhooked it for like 10 seconds and then plugged it back in and it stopped for a little bit. try that and it will at lease eliminate that if it doesnt work.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nastyeghatch &raquo;</TD></TR><TR><TD CLASS="quote">it could be the map sensor on the backside of the throttle body, i had a b16 in a rex and it used to do it all the time. a buddy of mine at a shop unhooked it for like 10 seconds and then plugged it back in and it stopped for a little bit. try that and it will at lease eliminate that if it doesnt work.</TD></TR></TABLE>

map sensor is on the top side of the throttle body and the tps is on the backside of the throttle.

 

throttle body gasket looks good. I may replace it just for the hell of it. I'm assuming it has something to do with the IACV... but I don't know what I need to do about it. Does it need to be adjusted or replaced or what?

 

when you say you wiped down the iacv, what do you mean? did you spray carb cleaner into it and let it dry?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ziich2 &raquo;</TD></TR><TR><TD CLASS="quote">throttle body gasket looks good. I may replace it just for the hell of it. I'm assuming it has something to do with the IACV... but I don't know what I need to do about it. Does it need to be adjusted or replaced or what?</TD></TR></TABLE>

sorry

 

funny how there are several threads with the same prob and no one's come up with a solution better than "check your IACV"

 

well, since that hole IS the EACV, then you should check it with a multimeter and see if it's within spec

 

what's an EACV?

 

Why is there only one hole in your throttle body? There should be two?

When you put your finger on the top hole does it die or keep idling? My guess is idle correctly. Somewhere you've got a vacuum leak. It could be a lot of vacuum hoses, and I don't know much about JDM engines, cause over here we have a FITV, and apparently you don't if you've only got one hole in the TB

If you cover up your IACV and the car dies, then I would replace the IACV, if the car doesn't die that means it's getting air from somewhere else and you need to find that vacuum leak.

 

that should help
https://honda-tech.com/zerothread?id=1003988

 

So did you check your tps... Turn off car. Unplug the sensor on the back side of the TB.. Turn on car...check if anything changed..Turn off car and plug back in. If it changed than its the tps. If not check the other sensors and check vac lines for leaks.

 

Yeah sounds like tps..Imo it is. Let us know if you check and what the results are.

 

FITV or fast idle thermal valve could be your problem its on the back of the intake manifold take it off and tighten it as much as possible

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRXified &raquo;</TD></TR><TR><TD CLASS="quote">that should help
https://honda-tech.com/zerothread?id=1003988</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by beaneg6 &raquo;</TD></TR><TR><TD CLASS="quote">FITV or fast idle thermal valve could be your problem its on the back of the intake manifold take it off and tighten it as much as possible</TD></TR></TABLE>

There might be a vacuum leak where the FITV should be, but he's got a setup different than normal.


Modified by Falqon at 9:22 PM 9/10/2005

 

assuming that's my TPS sensor...

when unplugged, the car idles at a steady 2000 rpm.

I'm not sure that it's a vacuum leak because when the TPS is plugged in, and I start up the car, it idles at 1300 or so. If i blip the throttle at all, THEN the revs start to bounce. So if I start the car up and don't touch the throttle, it'll idle steady at 1300.

When i plug the hole to the IACV, the car idles at a steady 800

 

did you try to set the minimum idle by unpluging your aic while car is running adjust your throttle set screw untill it almost stalls(very low idle 800ect)....next reset computer and plug your aic back in.....this suggestion worked for me on my D16Z6....very Diff motor, but hopefully this is a help..

 

I HAD THE SAME PROBLEM YOU NEED TO <U>BLEED YOUR COOLANT SYSTEM</U>.IF THAT DOESNT WORK THEN CHECK YOUR IACV.JDM MOTORS ALSO HAVE AN FITV-TB WITH ONLY ONE HOLE CANT BE CHECKED TO SEE IF THE FITV IS BAD CAUSE THE IACV AND FITV SHARE THE SAME HOLE.
THE FITV ON MY CAR WAS STILL SUCKING AIR WHEN MY CAR WAS WARM AND THEY SAID ITS NOT SUPPOSE AND THEY SAID TO COVER UP YOUR IACV HOLE AND IT SHOULD DIE OR SPUTTER-AND IF IT DID THIS IT WAS YOUR IACV THAT WAS BAD..BUT IF YOU THINK ABOUT IT WHERE IS THE AIR GONING TO COME FROM SINCE YOUR TB IS CLOSED COMPLETELY ON IDLE, SO OF COURSE YOUR CAR WILL DIE CAUSE IT WONT BE GETTING ANY O2.
<U>ALSO CHECK YOUR IDLE ADJUSTING SCREW IF ITS ADJUSTED TO FAR OUT THEN IT WILL ALSO CAUSE YOUR CAR TO IDLE UP AND DOWN. ALSO CHECK YOUR TB AND IM BOLTS. </U>