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Let's talk FIAV and ISC block off plates!

cheekychimp

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Apr 19, 2004
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East Sussex, U.K.
I have an aftermarket throttle body but the FIAV and ISC assembly bolts straight onto it. I'm having a couple of idle issues and I want to rebuild that part. Now I know I can get new o-rings/gaskets, a new ISC, new throttle closed switch but what about the FIAV itself. As far as I know it's just a wax plug so if it is faulty can it be replaced or do you have to purchase the entire lower assembly?

I also know there are a number of block off plates around. One that blocks off everything including the ISC and just replaces that entire assembly. Another that goes between the TB and the assembly and retains the ISC function whilst eliminating the FIAV and an EGR block off. Does any one have any info on the benefits and disadvantages of each.

For reference, Hong Kong is a tropical climate so for 10 months of the year or more it really never gets cold. It also means that I have NOT deleted my A/C and I have no plans to do so. With a properly functioning FIAV I get an extremely fast idle at start up when it is warm, which I really don't like.

I'm leaning towards an FIAV block off that retains the ISC (for the A/C) but I just want to find out from those that have gone that route if the car is difficult to start or stalls a lot until it warms up because that would bug me.

I also have a 12v solenoid activated FIAV lying about that I could install on a toggle switch in place of the stock FIAV. The advantage of running that is that I could get some restrictors and play around until I get the correct start up rpm and once I have that done I could run it off a temp switch to make it fully auto.
 

89Mirageman

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Jul 5, 2006
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Stantonsburg, NC
I bypassed the throttle body coolant hoses on my 95 GS-T back in the day and it took the car quite a while to idle down when it was cold outside. I hooked them back up and the problem was gone. I would think that this would be the same thing as eliminating the FIAV.
 
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SouthCaliVR4

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Jul 31, 2010
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North county San Diego
Not so, in your case the valve saw cold for a much longer period till the radiant engine heat made it's way to the wax & closed the port.

Paul, You may have to feather the throttle a little when it's cold but not for long.
 

ktmrider

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Sep 10, 2007
Messages
3,128
Location
Tempe, AZ
Paul I did the FIAV block-off and coolant bypass, can't rave enough about it. Rock solid idle both cold and hot including A/C on-off.

No noticable effect on cold-start other than taking a few extra spins of the starter to fire ( but it could be my old injector seals ) even in sub-zero centigrade temps.

Do it!
 

vtecds1

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Jan 16, 2004
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1,705
Location
Las Begas
This mod looks simple to do. I haven't done it yet, but I will very soon
 

boostedinaz

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Apr 20, 2006
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Location
Scottsdale, AZ
I have blocked the FIAV on all my DSMs and 1101. For 1101 I just filled the FIAV with JB weld and let it cure for a day or two. That left the IAC to control the idle and it worked perfectly. Rock solid idle all the time and it even had a high idle for warm up in the mornings.
 

cheekychimp

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Apr 19, 2004
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East Sussex, U.K.
Sounds like a plan then. What does the EGR block off do? We have no emissions laws over here so any disadvantages to doing this while I am in there?
 
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alansupra94

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Mar 3, 2010
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Wayne,NJ
I am tempted to do this mod. But my car is fine right now so I dunno /ubbthreads/images/graemlins/rofl.gif
 
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SouthCaliVR4

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Jul 31, 2010
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North county San Diego
Quoting cheekychimp:
Sounds like a plan then. What does the EGR block off do? We have no emissions laws over here so any disadvantages to doing this while I am in there?



with tuning blocking the EGR will give you more power but the Egr does allow for more aggressive timing so you may see some knock on a stock tune.
 

SleepinGVR4

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Feb 12, 2003
Messages
2,483
Location
Danville, Pennsylvania
I just figured no one in the galant/dsm community gives a sh*t about emissions so they removed them. Also if you car has some miles they get totally caked up with carbon build up.
 

belize1334

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Nov 18, 2003
Messages
3,316
Location
Bozeman, MT
I like blocking the FIAV but keeping the ISC. It helps with stabilizing the rpms when you apply the brakes (boost draws vacuum) and accessories. I've also tried with both blocked and the drivability wasn't as good. The idle raises considerably after the engine warms up so you either have to baby it on cold-start or be happy with a fast-idle after it's all warmed up... Recently I've been thinking about re-enabling the FIAV and blocking the ISC. That'd remove the electric control but allow for better cold-start...
 
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1990ggsxnj

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Nov 21, 2008
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525
Location
Blackwood, NJ
I've done the block off (screw in method with JBWeld) on a few cars and in cold temps had no issue keeping an idle at first startup. The ISC did just fine, though as stated already - took a few more cranks and sometimes a second of throttle to get it idling normally.

Btw, 3 out of 4 adjusters were easy as pie to adjust down.. the runt of the litter was a B*tch! Blow torch and all it took like an hour and a half to get it all of the way down.
 
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cheekychimp

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Apr 19, 2004
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Location
East Sussex, U.K.
Quoting SouthCaliVR4:
Quoting cheekychimp:
Sounds like a plan then. What does the EGR block off do? We have no emissions laws over here so any disadvantages to doing this while I am in there?



with tuning blocking the EGR will give you more power but the Egr does allow for more aggressive timing so you may see some knock on a stock tune.



That's great info! /ubbthreads/images/graemlins/smile.gif

If that's the case, I'll probably just clean everything up for now and consider an EGR block off if I end up putting ECMLink in this car at a later date.
 
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turbowop

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Apr 29, 2001
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11,971
Location
Yakima, WA
I blocked off the FIAV on 1051 back in the day when it was giving me cold idle surge. I used the JBweld method and kept the ISC functional. Problem solved and no issues. That car also has no EGR valve as the Magnus intake manifold has no provision for one, nor does any other aftermarket intake manifold as far as I know.

On 503 the EGR is blocked off, but I kept the FIAV and ISC both functional as I didn't have any idle issues. Now I'm starting to get some surge if I drive it before it's fully warmed up after startup, so pretty soon one of these weekends I'll probably pull the throttle body and block off the FIAV. It's my ski car and sees some pretty cold temps up on the mountain, but I think it'll be fine.
 

dsm10o0

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Jun 16, 2010
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San Jose CA
Didnt want to make new thread so ill bump this one up since its only a few weeks old.

Anyone got a link to the JB weld method?

Ive been having a really high idle at first start up and once warmed up, it surges until its fully hot, it settles down to normal idle.
 

boostedinaz

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Apr 20, 2006
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4,085
Location
Scottsdale, AZ
Quoting dsm10o0:
Didnt want to make new thread so ill bump this one up since its only a few weeks old.

Anyone got a link to the JB weld method?

Ive been having a really high idle at first start up and once warmed up, it surges until its fully hot, it settles down to normal idle.



I can't remember the acual ports on the FIAV but I just take the lower portion of the TB off and get it nice and clean. Take some brake cleaner and spray it in one of the coolant lines and see what "square" it shoots our of then repeat for the other coolant line. Those are thep assages you want to block off. When I did mine I also took a thin piece of sheet metal and clamp it to the FIAV so the JB weld would be nice and flush with the mouting service.

I hope that made sense.
 

I use this guy on most of the dsm's ive had once the FIAV started leaking. Eliminates the the FIAV and keeps the ISC. Like said earlier takes a few more cranks on cold mornings but other than that it worked pretty well.



Quoting belize1334:
I like blocking the FIAV but keeping the ISC. It helps with stabilizing the rpms when you apply the brakes (boost draws vacuum) and accessories. I've also tried with both blocked and the drivability wasn't as good. The idle raises considerably after the engine warms up so you either have to baby it on cold-start or be happy with a fast-idle after it's all warmed up... Recently I've been thinking about re-enabling the FIAV and blocking the ISC. That'd remove the electric control but allow for better cold-start...





I bought a TB that all ports have been welded shut FIAV and ISC both removed. The guy i bought it from had tapped a bolt that i can screw in and out to adust idle. That works pretty well expecially with idle, its a bear to start when its cold,but since install ive never had another idle problem.
 

If you have the cyclone intake or JDM ecu there is no EGR valve. So you'd allready be blocked off /ubbthreads/images/graemlins/cool.gif
 
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