fiav block off questions [Merged 11-8]

[96whgsx]

I did a boost leak test recently and I found a very good sized leak probably on the TB shaft seals. So, I'm just going to replace them and while the TB is off, I was deciding whether I should block off the FIAV and blocking off both the FIAV and ISC. I know that some people have had trouble with cold starts on cold days but the weather here doesn't go below 50 F so, I'm not too worried about that. Also, the vfaq for removal/bypass of the FIAV isn't working, so I have yet to read an write-up/article on this subject. I do know that you can JB weld one of the ports or buy a blockoff plates and re-route the coolant lines to bypass the throttle body. Thanks in advance for the replies.

 

[SkURTnDSM92T]

http://www.vfaq.com/mods/wayback/BradBauer/engine/surge.html

 

[96whgsx]

Actually, I was more interested in the FIAV part, not idle surge in general.

 

[MyBeatGSX]

My ISC drivers in the ECU are fired, so I can tell you from personal experience that its no fun running without an ISC. You have 2 options. You can have a high (850rpm) idle during the day with the lights off and have a normal (750rpm) idle at night with the lights on. Or you can readjust for day and night every time you drive somewhere... and then still have problems with occational stalling or 900rpm idle depending on the weather and how you were driving the car. If you have/use the AC then you're SOL, you'll have to get out and adjust the idle up before you turn it on or just run around with a 1,100rpm idle the rest of the time so it doesn't stall with the AC on.
I have to adjust my BISS at least every other day and sometimes multiple times a day depending on temperture changes. I now keep a screw driver in the car. Its funny to explain to random people or passengers why I have to adjust something under the hood every time we into or out of the car.

I'd block off the FIAV but not the ISC if its working.

Check out what they do here, maybe this will give you an idea...
http://www.ffwdconnection.com/flow.shtml

 

[jimmybosox]

OK -

So all winter I've been having idle issues. Crazy surging about 3 minutes after start up. Fairly frequent P0505 code being thrown.

I searched the forums and figured it was the ISC. Replaced that with a new one from dsmisc.com. That didn't fix it.

Did some more forum searching and figure it could be the FIAV. Decided to try to buy a throttle body off the classifieds here and send it to throttlebodys.com to be rebuilt then install it on the car.

Today I'm looking under the hood at the throttle body (and my Chilton manual) to see if my meager mechanic skill will allow me to be able to remove/install a throttle body myself. Looking at the bottom of the throttle body, I see 2 fairly large ports/nipples with nothing attached to them. More forum/manual searching and I'm guessing these are the coolant in and out. Can anyone confirm this? Is there anything else they could be for?

My forum research leads me to believe that if the coolant isn't running through the bottom of the throttle body, a FIAV blockoff plate should be installed or it can cause idle problems such as I have been having. Steve at throttlebodys.com doesn't support this. He recomends not blocking off the FIAV even if the coolant lines aren't attached to the throttle body. He's confident that once he's provided me with a rebuilt throttlebody with properly functioning ISC and TPS, the idle problem will be solved. And if not, the problem would then be a boost leak or a bad ecu.

I have not done a boost leak test because 1. A rebuilt 6 bolt was just installed a little while ago by a good shop that I trust. I assume any boost leaks would have been identified/remedied at that time. 2. The car drives great, holding steady at 17 lbs of boost whenever I get after it. 3. Even after reading how to do a boost leak test, I don't have the combo of tools, space, know-how to do it myself.

Another question. If I don't hook the coolant lines back up to the throttle body, should they be capped? Does that matter at all?

Of course, today with the temp at a balmy 35 degrees, the car ran like a champ...no idle problems at all.

Thanks in advance for your assistance and info.

Jimmy

1997 TSi AWD Turbo with 6 bolt swap (1G block and 2G head)

 

[turbosax2]

Yes, the 2 large nipples on the throttle body are for the coolant lines for the fiav. That is all they are for.

I can only assume Steve knows his stuff. However, this is the plate people normally use when they get rid of the fiav but want to keep their isc:
JM Fabrications

Don't trust the shop to have fixed all the boost leaks. A proper boost leak test is one of the best forms of maintenance you can do to your car to make sure it's running at its full potential. You need very few tools, very little space, and only a little know how. You WILL need an air compressor or an air tank that you can fill up at the gas station. You will also need a boost leak tester.
IC Pipe Tester

If you don't hook the coolant lines back up to the throttle body, you must cap the nipples that coolant flows through at the thermostat housing and water pipe. If you didn't, coolant would come out of these holes and go everywhere. You don't have to cap the 2 nipples that are on the throttle body.

Also, take a look here:
Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

 

[turborebel]

Are you saying that 35 degrees is warmer than normal and the car runs better?

 

[jimmybosox]

Turbosax2 - thanks for the info.

I've seen that JMFab FIAV block off plate before. I think Steve at Throttlebodys.com only offers the complete blockoff plate, not one like that which would eliminate the FIAV but keep the ISC. 1 question...JMFab only shows a 1G plate...is the 2G throttle body the same? Will that plate work on my throttlebody? If so, I may buy that plate and send it to Steve along with my throttlebody.

I know I should do a boost leak test, and I will...eventually. My neighbor has a heated garage and an air compressor. I had seen that article before on the do-it-yourself boost leak tester. Thanks for the link.

Thanks for the other link as well. I found that when I first had idle issues and I've been trying to test the things listed there.

turborebel - yes, 35 degrees is warmer than it has been around here (WI). The idle issues for me seemingly only occur when the temp is 10 degrees or colder. 24 degrees this morning and, again, the car started right up and idles fine. IMO this is compelling evidence that the FIAV is the problem. Without coolant running through the bottom of the throttle body, the FIAV must not be able to function correctly.

 

[Gstclipse69]

I've seen that JMFab FIAV block off plate before. I think Steve at Throttlebodys.com only offers the complete blockoff plate, not one like that which would eliminate the FIAV but keep the ISC. 1 question...JMFab only shows a 1G plate...is the 2G throttle body the same? Will that plate work on my throttlebody? If so, I may buy that plate and send it to Steve along with my throttlebody

Yes the 1g and 2g throttle bodies are the same, and the plate will work.
--> Boost leak test

 

[russgvrs]

Somebody correct me if I am wrong but isn't this why the oem installed the fiav. So engine coolant can warm the intake and have better idle at cold temps? Have you tried hooking the coolant lines back up? It seems to me eliminating the fiav has the drawback of hurting cold temp performance. That plate will work on all but the 1990 models.

 

[Street_Killer]

I was wondering if an important part of blocking the fiav is also blocking the coolat lines? I had the fiav air passage and coolant lines blocked off originally, then something happened and the coolant line block was gone and no longer blocking it, causing my idle to surge again. So does the coolant lines being blocked have anything to do with the fiav block off working or do I have other problems?

 

[gsxtasy]

Idle surge is due to air getting past your throttle plate, i don't see how the coolant lines would have anything to do with that? The lines on your TB don't even have to have anything hooked up to them, just the lines on the water pipe have to be looped back together, so i fail to see how that can have anything to do with it, maybe I'm mistaken.

 

[Street_Killer]

Anyone else? Should I try blocking the isc hole?

 

[boostedinaz]

This depends on the issues you are having. Personally I would never block off the ISC as an erratic idle annoys the hell out of me. On both my daily driver GVR4 and my Talon I have filled the FIAV ports with JB weld and left the hoses ends open to the air. This way the car still has a steady idle and can compensate for extra load on the engine such as A/C, but I don't have to worry about any idle issues related to the FIAV.

If you don't like the JB weld idea here is a plate that you can use as well.

http://www.jmfabrications.com/catalog/product_info.php?cPath=21_23&products_id=57

 

[Street_Killer]

What do you mean by ports? Isn't there only one air port for the fiav and one for the isc, then the middle port is the coolant, and the other longer port where the air enters for both the isc and fiav.

 

[gsxtasy]

No, there are 2 for coolant, one for in and one for out. He means leave those open, because with a FIAV block off you don't use them.

 

[Street_Killer]

Ok, so I just looked into that link, and I assumed that your suppose to block off the other opening. This one shows the left side being left open, and I thought you were suppose to leave the right side open. Currently i have the left sie closed?

 

[boostedinaz]

Just block the ports that the JMFab plates covers up. You can also get a can of WD40, carb cleaner, or any other spray and spray it into the hose ends. It will spray out the port in the lower throttle body that needs to be blocked.

 

[Street_Killer]

ok, well i have the fiav air port blocked and the coolant ports. But can I get a simple yes or no answer? Will the coolant affect anything whether its blocked or not?

If this doesnt solve my idle surging (when I did this block off the first time it fixed it til the silicone was sucked out or something and instantly after began surging) then what could it be?

 

[boostedinaz]

ok, well i have the fiav air port blocked and the coolant ports. But can I get a simple yes or no answer? Will the coolant affect anything whether its blocked or not?

If this doesnt solve my idle surging (when I did this block off the first time it fixed it til the silicone was sucked out or something and instantly after began surging) then what could it be?

You won't run any coolant lines to the TB when you block off the FIAV.


It could be a host of things. Have you done a boost leak test, is the ISC in good working order, are your drivers for the ISC in good working condition?

 

[Street_Killer]

Well I got pissed off and blocked the isc port off, but what really makes me mad is what I did not see. One of the screws on the throttle plate that holds the throttle plate on was missing, and allowing tons of air past the throttle plate. Hmm I wonder if that was my problem.... More then likely. So I just said screw it and did not take all the silicone out of the isc port. The car idles good after I adjusted the biss screw, but when it gos warm the rpms go up to about 1500. It was higher but I adjusted it some. So now im gonna let the car cool down and see if it idles at a good rpm when fully cold, and if it does ill just call it good.If it not ill take the silicone out and go from there.

 

[94cyclone]

Hey this one is old, but I'm new to DSM, and it looks like this guy never got an answer. I'd like to use jb weld to block off my fiav, but what about my isc, wouldn't unplugging it make the ce light come on?

 

[Archametes]

Can a 1G FIAV block off kit fit a early (1995 made in Dec. 94) 2G throttle body? Has anyone tried this? If so was a direct bolt on or did it have to be modified and in what way?

Thanks, Mike

 

[sd_ff22]

yes it will fit without being modified.
the housings are the same but different sensor and pipe directions.

 

[Archametes]

ok. thanks for the response.