Skunk2 70mm tb problem

[crobaa]

Hi guys, installed my skunk2 70mm tb last night. The car starts fine but after driving it, it won't idle correctly. Between 1-2000rpm mostly. Hunting quite wildly. I can also hear a louder air sucking sound from my intake too. I reused my original dc2r iacv and tps. Motor is b18c.

I've slackened off the throttle cable to ensure the tb is back in the closed position
Reset the ecu


Anybody know what could be causing this erratic idle?

[mooshie]

Vaccum leak?

[bennjamin]

likely vaccum leak as said above

but the reason is probably a tear in the tb gasket , or the vaccuum system doesnt line up on the TB vs the inlet mani side.

[crobaa]

The tb gasket is a thick thermal skunk2 one designed for the tb, and the tb is designed to work with stock manifold, I don't think there's a leak there but ill check it regardless. Would that explain the increased sucking from the intake? Sounds like a vacuum cleaner

[_CRX_]

There's two screws inside the throttle body that hold the butterfly in place...check there tight and still intact....

[Vvvtec]

The tb gasket is a thick thermal skunk2 one designed for the tb, and the tb is designed to work with stock manifold, I don't think there's a leak there but ill check it regardless. Would that explain the increased sucking from the intake? Sounds like a vacuum cleaner


There's two screws inside the throttle body that hold the butterfly in place...check there tight and still intact....

This, Ive read of several motors using skunk2 tb's that have ingested butterfly screws

[Evok]

Check for leaks above as said.
reset ecu and let it ecu relearn itself.....
no tune? 70mm upgraded from a standard b18 62mm is a big mindfk for stnd ecu

[Daveho1]

Check for leaks above as said.
reset ecu and let it ecu relearn itself.....
no tune? 70mm upgraded from a standard b18 62mm is a big mindfk for stnd ecu

this...

[crobaa]

Ok, ecu has been reset again. I've also backed off the throttle cable some more which seemed to help the most, which is strange because I could feel the throttle returning to the fully closed position before, but slackening it off definitely helped. Now the car only hunts about 400rpm up and down and not above roughly 1900rpm. There's a big brass screw on top of the tb, also the return position adjuster screw, would it help to tweak these a bit? Will check the butterfly screws are tight inside too.

[trism]

id be checking the butterfly screws are tight before i even turn the motor back on again.

[Daveho1]

i would be building an engine that requires a 70mm throttle body before you even turn the motor on again.

on the serious though... the tune dosnt consider the needlessly large throttle body and if your set on using it, then its worthwhile getting everything matched and then having it tuned.

[crobaa]

I'm gonna port match it this weekend then start hunting for a hondata. Engine will be worked in the future hence why I bought it.

[Baby Face]

my TB made my car hunt too, check the idle control screw.

wind it all the way down let the iacv control the idle.


i cleaned mine up and it freed gunk from the idle screw, plus i think i tweaked it by accident.
made the car hunt.

i thiought iacv was busted.

maybe air got into coolant is playing with the FITV.

take off the piping and with the car on put a finger over each hole in the TB on at a time.
the bottom should be the hole for fitv, the top for iacv. if u cover both and it runs normally then there is a leak. (check idle screw, vacuum hoses)

if covering the FITV hole fixes it then u need to wind down the FITV using the well known guide/diy. i blocked off my FITV as its not necessary, then helps eliminate one issue for certain.

[crobaa]

What's FITV? Where is this well known guide? My tb doesn't have the coolant hoses going to it so its possible air got in when I bypassed it. To bleed it I just open radiator cap, and run car with the front jacked up right?

[Baby Face]

http://honda-tech.com/showthread.php?t=2153910


check the idle control screw is down, it does leek enough to create an idle hunt!!!

[Rage King]

Did you install the TPS in its correct location/setting? you may need to re-calibrate your TPS to suit your new TB butterfly and may need to adjust the voltage on the TPS sensor.

there is a good DIY on here - try this first and see how u go,

http://www.ozhonda.com/forum/showthread.php?120191-Calibrating-the-Voltage-on-the-TPS

[crobaa]

Ok thanks guys!

[Super-DA9]

If you have a B18C7 it will not have an FITV.

If there are no leaks, and the manual idle control is adjusted correctly but you are still experiencing hunting idle, then you probably need to adjust the IAC duty cycle.

After I changed my manifold to a Skunk2 unit and my throttle body to 68mm I started to get these hunting idle issues too.

I plugged in a laptop to my S300/ECU and loaded up the tune in SManager. In one of the tabs there is an idle control screen with a slider bar that adjusts the IAC duty cycle. Move the slider up and down and keep reloading the tune file as you make changes until you find a point where the idle doesn't hunt anymore.

Also it is a must to recalibrate the TPS as Rage King suggested.

[crobaa]

Ok thanks. Can I add that the car idles fine at first, but after some driving it occasionally begins to hunt then eventually settles itself down. Gotta get me a hondata soon

[Super-DA9]

Ok thanks. Can I add that the car idles fine at first, but after some driving it occasionally begins to hunt then eventually settles itself down. Gotta get me a hondata soon

That's the issue I had. Duty cycle adjustment should sort it out.

[Evok]

You require a tune if u cant manage to play with the idle screw.
If ur tps is not set right it'll give a CEL.

Air in coolant can also hunt but doubt it....

[K20a-eg]

What manifold are you using? Dc2? Ek? Eg?

[crobaa]

Dc2r stock manifold

[K20a-eg]

okay first thing to do is slacken of the cable so the throttle isn't open.im assuming u tps is set up correctly 0.5v at closed on signal wire. 4.5 on wide open throttle (test with engine off!!) centre wire on tps. there should be a 5v input and a ground either side if I remember corretly
start car with throttle body exposed, there 2 ports inside throttle body that lead into the idle air control valve, cover these with you fingers,the car should die?
if it does you have no vacuam leak,if it doesn't theres your problem ( throttle gasket)(
if it doesn't remove the iac valve that has 2 x 12mm bolts on rear of intake,(undo both cooling pipes underneath it but release pressure from rad first so u don't burn yourself) and unplug it, clean this out as it maybe sticking.refit don't loose o rings top up cooling system and rest ecu. 20amp back up fuse in fuse box

if that's not it also on rear of manifold beside throttle body is a circular metal plate with 2 screws, open these up and don't lose them, there is a plastic cover in there that has a springy feel,turn it clock wise until its tight,then refit plate, there are all the main reasons for a hunt from the info u have provided.

I worked in Honda speacialist for years and carried out 100s of swaps and fitted all kinds of everything to d,b,c,h,f,n engines soif any one gets stuck il try my best to help ya out