Replaced IACV and Still High revs ?? FIXED !!

**Andrew21** · 12-09-2006 11:47 AM

Disclaimer: The following is provided as a GUIDE ONLY, and neither myself nor Ozhonda take any responsibility for the outcomes of someone else doing the following. You follow these steps at your own risk!

If most you guys have replaced the IACV and seemed to fix your " high idle " cold start problems then thats great !!! HOWEVER if you, like me, replaced your IACV and still the problem persist then try this !!.

1. Remove all Intake arm from Throttle body to air filter ( more room to move)
No Pic.

2. Locate the the Throttle Body and find the hose shown in this picture.

3. Once the car has been started for at least 2-5 mins feel the hose pictured and it should start getting warm, coolant should be running through this .. IF ITS NOT WARM THEN BINGO THERE'S YOUR PROBLEM !! A BLOCKAGE.

4. Remove the "helmet" shaped housing which the hose connects to on the side of the Throttle body which from memory is held on buy two bolts/screws.

5. Mine was all rusted up and gave it a good clean out with TB cleaner and wire brush ( DO THE SAME !! )

6. Seal it all back up with some gasket glue

7. Connect all hoses and pipes again and start her up and..

BINGO !!! Pipe is now warm and has coolant running through it which now engages the IACV PROPERLY !!!

Particular usefull for cars with high kms or imported motors...

Wynode edit: Added Disclaimer

**stanleym** · 13-09-2006 08:43 PM

thorugh cleaning the iavc (when taking the pipes out) coolant should run through one hose......is this possible way to tell no blockage in that pipe

**Andrew21** · 14-09-2006 10:38 AM

Possibly.. The easiest and best way is like i said above, just simply feel the hose if it gets warm/hot... If it does then theres your answer...

The hose im talking about doesnt connect to the IACV it connects to the other valve pictured above on the side of the throttlebody.

**CRXer** · 14-09-2006 06:24 PM

I didnt think the IACV had any control of cold start idle unless your playing with aftermarket ecus.
I thought it was purely up to the FITV(the other valve your talking about) to adjust the cold start idle.
Can anyone clear me up on this?
I think this is on topic?

**aimre** · 14-09-2006 08:29 PM

Originally Posted by claymore

That is the coolant line that heats up the TB to prevent icing in cold conditions.

No... thats the coolant going to the FITV. I just fixed mine this week.

**Professional** · 30-09-2006 01:47 PM

Good sharing !!

**dsp26** · 02-05-2007 08:10 PM

Originally Posted by claymore

That is the coolant line that heats up the TB to prevent icing in cold conditions.

I agree despite it being a "FITV".

I have removed both hoses connecting to this and joined them together with a hose connector nipple and i still get high idle on cold start and goes down to around 800rpm when warm.. no idle hunt!!

For those wondering why i did this, i installed full 6mm intake spacer kit (with replacement studs) which involved:
- Runners/Head spacer
- IACV/Plenum spacer
- TB/Plenum Spacer
- "FITV" Coolant bypass which consisted of the hose connector.

I have disassembled both the TB and this "FITV" and followed and studied every hole and path. That thing everyone cleans is obviously a thermostat also.

This is my understanding of it's functionality:
- Now when cold, the thermostat allows coolant to circulate through it to start getting it warm.
- The 2 holes on the bottom of the TB allow air through this path while the coolant starts to get warm to allow the air to heat up and cool the bottom part of the TB (where the bottom of the butterfly goes inwards on open throttle) which is a common freeze spot in icy countries.
- When engine coolant get's to temp, the thermo just simply regulates coolant and temp in the area.

Now the 2 holes at the bottom off the TB that connect through this "FITV" both have access to the plenum.. why would it matter when this "FITV" closes access in this path? the hole on the cable side will simply not get air flowing through it but the other will still get air though it as it leads to the hole on the other side of the butterfly.

The Idle issues caused from blockage of this "FITV" item actually affects the IACV (which controls the idle) as it connects before this and the coolant has nowhere else to go. This is evidently supported by my bypass setup where flow after the IACV is unhindered by the "FITV"

I am willing to prove my setup to anyone whose willing to have a look.... just trying to help