Trying to figure out a 3 month long issue. Idle is lumpy from 1oorpm to 1300 rpm,
no vacuum leak tried plugging hole to IACV and car dies. tried adjusting IDLE screw to no avail not getting better. unplugged IACV and get CEL and car doesnt run it dies... please LMK thanks!

LSVTEC TURBO

new rebuilt head
new rebuilt block
new gsr tranny with ls 5th

*****resolved*****

 

*update* sooo i went out and got some honda OEM radiator fluid, and for shitz n giggles i bled the radiator system... seemed to help , but still have searching idle.... seems it finds the idle spot , then it starts roaming again... maybe tune issue?>

 

In reply to:
https://honda-tech.com/forums/showth...4#post48801984
I'm not as familiar with turbo setups as I would like to be, but I'll try to help.

basically the ECU is sensing too much air past the throttle plate under expected idle conditions. causing injector pulse to be cut - surging idle

stock N/A engine surging idle potential causes (-FITV)
vacuum leak - gaskets - cracked hose - hose disconnected
Idle screw mis-adjusted
throttle plate not at idle position/throttle cable sticking or too tight
IACV sticking/dirty
Air in cooling system
map/tps out of calibration - doubtful - but in turbo setup I'm not sure?

I can't say a fuel map problem/tune issue couldn't cause this, but i wouldn't think it would come out of the blue.

b18xx? M/T? you disabled the FITV and installed a block off plate and gasket, I assume? Also, in your other thread, you had unplugged IACV before and it idled at 900, had you adjusted your idle screw closed and now it dies when unplugged?

 

if you disconnect the iacv and it dies, your idle is out of adjustment. with iacv disconnected, it should sit at 500rpm roughly. when you attempted to adjust the idle, if you did not have the iacv disconnected when doing so, it was done incorrectly. follow the FSM procedure for adjusting idle. also be sure to allow an idle relearn after clearing the iacv code.

 

after you have adjusted idle AS PER FSM PROCEDURE, if the hunting still occurs, engine running, try covering the throttle body bore with your hand. if the engine does not die right away, you have a vacuum leak

 

Ok I will try the procedure tonight. Now I wanted to note I went from obd1 block w obd2 head to both obd2 . The obd2 ls block has no charcoal box in the back. Therefore I have line off intake mani to pcv to open tube.... Should I plug that or is it mandatory ? It is turbo maybe I should run catch can setup? I'm not sure if this would cause an idle and pcv is only for emissions right ? I'll post after I try the adjust idle procedure.

 

The throttle body I have doesn't have an option for a fitv, my friend says its a Jdm one but I'm not sure, skunk2 gen1 intake mani (no emblems looks stock)

 

pulled IACV it dies immediatly.. .. also noticed if i hold a slight pressure on gas pedal it will stay idling at 900rpm... sooo maybe adjust throttle plate screw to be open more? I tried advancing the idle screw (flathead one on top) all the way and it didnt change anything..... so i put it back to where it was before...

 

maybe run that line from intake mani to pcv then to breather tube on valve cover?

 

if it died with the iacv disconnected, you need to adjust the idle higher and try again. once you have the idle adjusted to where it will run with the iacv disconnected, adjust idle to 500rpm (w/iacv disconnected). reconnect. clear code. allow vehicle to idle for 15 minutes undisturbed

does the line that you have open see engine vacuum? if you put your finger over it with the engine idling, can you feel suction?

 

yes i just checkd i feel suction , gave my finger a hard on

 

*now heres a question, can i run that line with the PCV on it, and route it to the top nipple on the valve cover? its open now, but its pushing air, where the PCV line is sucking... common sense, yet I have no experience with PCV system before this.* - not a good idea


now I am still struggling with idle issue, im going to delete PCV to intake Mani to get rid of that vacuum (possible vacuum leak). I deleted it with a bolt temporarily, however, it still searched for idle like it has been when it warmed up...

any takers lmk

 

that hose should be hooked up to the top nipple on the valve cover. the nipple is part of the pcv valve.

If the breather port hose cannot be hooked up to your intake piping (again not familiar with turbos) - put a breather filter on it.

this one valve/two hoses are basically your entire positive crankcase vent system.

 

if that hose sees engine vacuum, it should not be hooked up to the VC nipple. the VC nipple hose is supposed to pull ported (before the throttle plate) vacuum from the air cleaner boot.
if that hose you have sees engine vacuum, then that was a vacuum leak.

 

if you can take a pic of how you have this set up, that would help
we find out where the line you're talking about goes first. solve the idle issue after

 

*****resolved*****

This is what I did.

Plugged pcv tube off Im with bolt,
Turned idle screw all the way down
Adjusted throttle plate screw so it opened more, rpm at 3k
Unplugged iacv
Adjusted idle plate screw to where rpm dropped as low as I can get it to 500,
Played with idle screw and throttle plate screw until dialed in, then plugged in iacv and motor jumped to 1500rpm

Turned car off, the. Restarted and let car learn idle, adjusted as necessary...

No more hunting idle

 

it was probably the vacuum hose you had disconnected. after plugging it, you were able to set idle properly.