The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support ExtremePSI
Please Support STM Tuned

FIAV fast idle air valve

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Ben W

Probationary Member
25
2
Mar 7, 2017
Camp Lejeune, North_Carolina
And should it be hooked up, or should I get a seal on it
You must be logged in to view this image or video.

Its the piece dead-center of the image, slightly outta focus
Here is another image to help get a reference of where this is exactly

You must be logged in to view this image or video.



Thanks for any info!
If you need anything else to answer, just let me know
 
Is this what you’re asking about?
You must be logged in to view this image or video.
If so, that is your fiav, fast idle air valve. There’s an in and an out. One end goes to the thermostat housing and the other goes into the water pipe. It’s there to give you a higher idle by letting air bypass the throttle body. Once warm coolant flows through it, it will close the bypass which then brings your idle down. PO probably looped or blocked the ports on the tstat housing and water pipe.
 
Is this what you’re asking about?
You must be logged in to view this image or video.
If so, that is your fiav, fast idle air valve. There’s an in and an out. One end goes to the thermostat housing and the other goes into the water pipe. It’s there to give you a higher idle by letting air bypass the throttle body. Once warm coolant flows through it, it will close the bypass which then brings your idle down. PO probably looped or blocked the ports on the tstat housing and water pipe.
Yes, thats what im referring to

Hmmm

So I dont need to worry about it?
Should I put a cap on it?

If, for whatever reason, the PO didnt block/loop it, or at least not properly, what symptoms would there be?

I do have idle surging when the engine is hot, and I get stuck in stop and go traffic
#1 suspect is my throttle cable needs adjustment

But I noted this while looking around in my engine bay
 
You don’t have to worry about it. If you want the fiav feature, you’d have to get coolant hoses, hook them back up and remove the block off plate, as long as the fiav is functioning properly.

Look at the rear of your thermostat housing and you’ll see a hose that runs to the water pipe. That’s the most common way people do this. Think I can see the hose in that pic.
You must be logged in to view this image or video.

You’ll have to remove the fiav to see if they installed a block off plate. When you do a fiav delete, you’ll have to hold the gas pedal open slightly on cold start.

Here’s a good read on idle surge

 
If it's not blocked correctly then you'll get idle surge as the car warms up. I recall it doesn't open up until the car warms up so it won't even show up as a leak on a boost leak test. Took me a couple years to realize the previous owner didn't do this correctly. Never assume the previous did anything correctly.
 
Without blocking off the FIAV passage it needs the coolant lines attached so that it will close (not open) its air bypass as the engine gets up to temp. The FIAV's job is to raise the idle speed until the engine warms up by allowing additional air to bypass the throttle butterfly.
 
If it's not blocked correctly then you'll get idle surge as the car warms up. I recall it doesn't open up until the car warms up so it won't even show up as a leak on a boost leak test. Took me a couple years to realize the previous owner didn't do this correctly. Never assume the previous did anything correctly.
My idle is fine during warmup

The only idle issue I have is surging when the engine is hot and I get stuck in stop-and-go traffic
I think thats due to my throttle cable needing adjustment
 
The only idle issue I have is surging when the engine is hot and I get stuck in stop-and-go traffic
I think thats due to my throttle cable needing adjustment

Perhaps, or it might be related to the fact that without coolant passing through the FIAV it stays open like in warm-up mode allowing additional air to bypass the butterfly just like a over tight throttle cable would.

So check the cable since it's easy and then if you still have a surging issue fix the TB.
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top