Car wont idle after FIAV BLOCK OFF

[SnowBird]

I have a 90, I replaced the ISC motor with a big bolt, and then where the FIAV oulet was I ran a bolt through it until it pressed into the throttle body opening. Should I have not ran this bolt all the way through the throttle body and left that passage open? The idle really isnt responsive to the biss screw at all. This is my first TB tinkering so I really am not sure whats going on, but my surge sure did stop, it use to idle at 3K.

 

[Gstclipse69]

Did you block the coolant lines to the throttle body? I believe you need to fill the holes (2) that go to the fiav with jb weld to completely block it off. Or just get or make a complete block off plate. Search for fiav blockoff and you'll see a pic of what passages to block off. I did it and my surge went away for awhile then it came back again...??

 

[klipschaudio]

Do not remove your ics.

Heres a tip I posted on dsmtalk a while back that helped me get rid of jumpy idle, assuming your tb sensors are good and you have no boost leaks this may be your solution.


"I thought I'd share this and hopefully help someone struggling with crappy idle.
I had idle on 1G that would jump up and down, and nothing would fix it, I cleaned the TB check ics etc... The last thing I did was take the plate off of the TB that covers the coolant passage, it has a threaded circle (with a hole in the center) that will go up and down depending how you twist it, under the it there is a thermostat that opens and closes the center hole, I took it out, took the thermostat, boiled it and tested it was good, the plate however was almost unscrewed all the way, I screwed it in enough to allow the thermostat to be able to do its job, put it back on the car, and like magic, the idle was perfect. The idle recently became jumpy again, I took the TB out and screwed in the plate farther again, it became loose I guess, and again, the idle became perfect. You could probably use a special glue paste so it would never unscrew again. Anyway, this causes me to believe that if your idle is bad, and your TB ICS and other sensors test good, that is your problem, and the benefit of fixing it instead of blocking it off is no harsh idle at start up. Hope this helped, Tks."

 

[SBR Joe]

Removing all that junk on a 90 tb doesnt work like a 91-94, i tried it with no success. My advice would be to pick up a 91-94 tb and wire in the tps plug, and use a blockoff plate to block tha FIAV and ISC.


Joe

 

[project95gsx]

Do not remove your ics.

Heres a tip I posted on dsmtalk a while back that helped me get rid of jumpy idle, assuming your tb sensors are good and you have no boost leaks this may be your solution.

Does this work on a 2g as well? I've got some idle issues that come up pretty randomly (mainly high idle). Thanks.

 

[SBR Joe]

Does this work on a 2g as well? I've got some idle issues that come up pretty randomly (mainly high idle). Thanks.

Yours works like a 91-94 style, you can just remove the bottom half of the TB and block it off with a block off plate.


Joe

 

[klipschaudio]

Does this work on a 2g as well? I've got some idle issues that come up pretty randomly (mainly high idle). Thanks.

Should be the same, if your sensors are working and no boost leak, that may be your problem also. This was done on a 1G.

 

[project95gsx]

Yours works like a 91-94 style, you can just remove the bottom half of the TB and block it off with a block off plate.


Joe

What's the difference between this and your post? Why would someone want to totally eliminate the ISC motor? How does the car idle with no ISC (Example: air conditioning compressor coming on)? Also these products say for 91-94 cars, will that work on a 2g? Thanks.

 

[Gstclipse69]

The differences between the two block off plates are that one of them goes in between the top and bottom of the throttle body that blocks the passages to the fiav. The other plate is a block off plate that removes the lower half of the throttle body. In essence it removes the fiav and the isc. I believe the idle then relys only on the biss when the isc is removed. (Someone correct me if im wrong). The only drawback is a rough start and idle when its cold. You'll have to give it some gas for a minute for it to idle regularly. These plates should work on a 2g as well. I'm pretty sure the lower section of the throttle body is the same on both 1gs and 2gs. The opening is just the larger 60mm on the 1gs.

 

[SBR Joe]

The differences between the two block off plates are that one of them goes in between the top and bottom of the throttle body that blocks the passages to the fiav. The other plate is a block off plate that removes the lower half of the throttle body. In essence it removes the fiav and the isc. I believe the idle then relys only on the biss when the isc is removed. (Someone correct me if im wrong). The only drawback is a rough start and idle when its cold. You'll have to give it some gas for a minute for it to idle regularly. These plates should work on a 2g as well. I'm pretty sure the lower section of the throttle body is the same on both 1gs and 2gs. The opening is just the larger 60mm on the 1gs.

This is correct. With one it is just a "bypass" plate it goes between the tb and the bottom half still blocking off the coolant lines but keeping the isc. The other completely blocks off the entire thing. Drawback, they will idle rough when cold. If entirely blocked off it will idle at whatever the BISS screw is set at when warmed up. And yes thay will work on a 2g as well.



Joe

 

[blcknspo0ln]

I am experiencing this as well. I've never had much luck with good ISC's, so this time I decided to use JMF's block off plate to remove the lower portion of the TB. Why? To see how the benefits are. I wanted to see if running without out the FIAV and ISC was a benefit for a car that was purpose built for some abuse. The engine definitely does not like cold starts and I have to give it a bit of throttle when cranking it on and holding it for a bit to let the idle catch, after that, it's pretty smooth sailing. I'll report back in a bit once I get a couple more miles on the engine.

 

[Ludachris]

Edited a couple posts above and removed some links - vendor rule violation.

 

[SBR Joe]

Edited a couple posts above and removed some links - vendor rule violation.

My bad, just showing it so everyone knows what im talking about.




Joe

 

[SnowBird]

Did you block the coolant lines to the throttle body? I believe you need to fill the holes (2) that go to the fiav with jb weld to completely block it off. QUOTE]

Didnt have to block them off, I just took off the coolant lines.

Do not remove your ics.
QUOTE]

I removed it, but replaced it with a bolt.

Removing all that junk on a 90 tb doesnt work like a 91-94, i tried it with no success. My advice would be to pick up a 91-94 tb and wire in the tps plug, and use a blockoff plate to block tha FIAV and ISC.


Joe

Thats the answer I was looking for. My BISS screw always wants more air, after every test drive I have to back it out. I guess Im going for the 91-94 TB and start over.

 

[SnowBird]

Did you block the coolant lines to the throttle body? I believe you need to fill the holes (2) that go to the fiav with jb weld to completely block it off.

Didnt have to block them off, I just took off the coolant lines.

Do not remove your ics.

I removed it, but replaced it with a bolt.

Removing all that junk on a 90 tb doesnt work like a 91-94, i tried it with no success. My advice would be to pick up a 91-94 tb and wire in the tps plug, and use a blockoff plate to block tha FIAV and ISC.


Joe

Thats the answer I was looking for. My BISS screw always wants more air, after every test drive I have to back it out. I guess Im going for the 91-94 TB and start over. But first Im going to be a crackhead and try drilling a tiny hole through the butterfly in the TB and see if thatll let enough air in to manage it with the BISS.

 

[klipschaudio]

Well, if all else fails, try my method, and let us know what it yields.

 

[project95gsx]

Mine's fixed, I took the one good coil out of my old ISC, and replaced the bad one in my newer ebay ISC. Works great. Check your ohms! ~30 is good.

 

[this_tsi_8urV8]

I just bought a rebuilt 1g N/T throttle body ported. As of now I have a stock 1g Turbo throttle body. Works great, but I replaced my intake manifold and want to remove the bottle neck I have there. I ordered it with FIAV block off. Does not have the coolant lines or a place to connect my ISC/IAC. What do I do now? Just leave it as is? Return for one that has that portion there, but the coolant lines blocked?
OR should I put in my other half, that has the ISC/IAC and coolant lines to the newer body?
Thanks.

 

[SnowBird]

I just bought a rebuilt 1g N/T throttle body ported. As of now I have a stock 1g Turbo throttle body. Works great, but I replaced my intake manifold and want to remove the bottle neck I have there. I ordered it with FIAV block off. Does not have the coolant lines or a place to connect my ISC/IAC. What do I do now? Just leave it as is? Return for one that has that portion there, but the coolant lines blocked?
OR should I put in my other half, that has the ISC/IAC and coolant lines to the newer body?
Thanks.

Most likely the lines are missing, they would remain if the TB was a 90, but then they couldnt block it off. So Im gonna say they are gone, unless you actually ordered a FIAV BYPASS valve instead without knowing. Hope for that.

 

[this_tsi_8urV8]

Nope, I ordered it blocked off. Its a 1g NT, not sure what year, but early 90's. I was told just to leave it like that it'll be a lil pain to deal w/hold the gas pedal, but better having to deal with the iac and bad idling.

 

[meliketoball]

Aren't you supposed warm the car up before it can idle properly? I think you are.

 

[this_tsi_8urV8]

You are, but I am not certain how long. A veteran DSMer told me bout 30 sec and holding it at 1.5-2k RPM.

 

[illeffekt vr-4]

The amount of time it takes is different from car to car. Some cars will idle just fine after keeping you foot on the gas for 30sec or so, while others may require 2-3min.