FIAV Block-off Plate/Vacuum/Brakes

[fourgsixthree33]

I just had my engine out to do a BSE. While it was out and waiting for parts, I got bored and decided to make a FIAV block off plate. I am using a 1G 7 bolt head, 1G TB, and 1G intake manifold.

Got the car finished today. Needless to say, I am having some issues with the idle. Started out the throttle cable was messed up. I adjusted that and it felt and sounded great. Then it felt as if the throttle cable was sticking. Also have idle surge.

It is hard to drive. I am sure that people that are walking on the side walk looking and listening to my car assume I am some punk that can't drive stick.

I can switch back to the FIAV and ISC at any time. I am hoping to fix my issue so I can continue to get rid of my coolant lines running to the TB.

I am also reading 0 vacuum at idle. While driving and decaccelerating, the vacuum will still show 0. But if I give it a little throttle while driving, it will read 10.

The brake pedal has been weird as well. Sometimes, I push the brake pedal and it is rock hard. Could this be because of the vacuum issue? Is the vacuum problem because of the idle?

 

[And_44]

Did you by chance attach the vacuum line back to the intake manifold from your brake booster?

And from what I've read there is a one way check valve for that line on 2g's

 

[007jimmy]

I can switch back to the FIAV and ISC at any time. I am hoping to fix my issue so I can continue to get rid of my coolant lines running to the TB.

You are running no ISC also??

 

[bryanwheat]

I'd just put the fiav housing back on. If you are driving the car much than you want to keep that on there. The car is going to idle like ass without the ecu having control of the idle thru the iacv. Right now it sounds like you have a vacuum leak going on with your makeshift block off plate.

 

[fourgsixthree33]

Did you by chance attach the vacuum line back to the intake manifold from your brake booster?

And from what I've read there is a one way check valve for that line on 2g's

Yep, it's plugged in.

You are running no ISC also??

Correct.

I'd just put the fiav housing back on. If you are driving the car much than you want to keep that on there. The car is going to idle like ass without the ecu having control of the idle thru the iacv. Right now it sounds like you have a vacuum leak going on with your makeshift block off plate.

This is a very good possibility. I have not been able to do a BLT. Air compressor is broke at the moment.

So, put the FIAV back on?

 

[007jimmy]

Yes. Running no ISC needs proper engine management to make it idle right. If you dont want the FIAV just pop off the freeze plug and turn the screw shut and loop the coolant lines. I would just keep the FIAV though as it helps your car warm up.

 

[tjohn23]

Block FIAV yes but use ISC it makes it easier to control idle without only relying on the biss screw, so i would say try to us a FIAV bypass plate and loop the coolant line with this the surge should disappear.

 

[fourgsixthree33]

Am I confusing the ISC with the TPS? The sensor I removed was the sensor on the FIAV unit. The sensor on the TB is still there.

Also, I was going to put the FIAV back on today but couldn't find the plug for it. Which harness is it in? What is the general area that it is located in?

 

[jpmxrider489]

The Tps is on your throttle body. The isc is on the fiav. The plug for the isc should be under the throttle body towards the battery. And the Tps plug comes out by the injector clips.

 

[fourgsixthree33]

I thought so.

Any pics of the plug? It is a big six prong square plug right? Maybe it is stuffed in my IM. I looked and looked. Couldn't find it.

Found one just like the plug for the TPS though. Don't remember what that goes to. Maybe the FPS or something for emissions.

 

[jpmxrider489]

The isc Is on your throttle body that looks like a square on the bottom. The Tps looks like the CAS which is your cam angle sensor on the left of your head. They look kind of the same and out of the same harness. Here's a pic of the cam angle sensor with the plug. Hope this helps.

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[jpmxrider489]

Here's a pic of the Tps plug and the isc on the throttle body. The Tps plug looks like the greenish one by the intake mani. The isc is the brown plug on the tb.

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[fourgsixthree33]

Thanks for the helpful images guys. I definitely cannot find the ISC plug. The TPS is there and just now realized the other plug that looks exactly like the TPS plug is the MDF sensor which I no longer have since I have a 1G manifold now.

The ISC plug is much much larger than the TPS plug. Almost looks like the o2 sensor plug. I found another plug exactly like the o2 sensor plug but it would not plug into the ISC. This plug is also down under the MAF so that wouldn't be anywhere near where the ISC plug should be.

Remember how I was having those throttle cable issues? Well it stopped all of a sudden and noticed the TPS came unplugged. With the TPS plugged in, I would have issues with the throttle. Without it, no issues. Anyone know why?

 

[91mits]

did you say, your using a 1g intake with a 2g head? that wont work right you know, the ports on the 1g intake manifold are too large..

 

[007jimmy]

Are you running a 1g TPS or a 2g TPS?? Also the ISC plug comes out of the injector harness near the TB.

 

[fourgsixthree33]

did you say, your using a 1g intake with a 2g head? that wont work right you know, the ports on the 1g intake manifold are too large..

Using the 1G 7 bolt head as well.

Are you running a 1g TPS or a 2g TPS?? Also the ISC plug comes out of the injector harness near the TB.

2G TPS.

 

[jpmxrider489]

Could it be an option the owner before you cut that plug off for a wire tuck or delete the wires he had before? If you cant find the plug that easy it almost has to be missing.

 

[fourgsixthree33]

Could it be an option the owner before you cut that plug off for a wire tuck or delete the wires he had before? If you cant find the plug that easy it almost has to be missing.

The car was mostly stock when I got it but this is always a possibility. I tried looking for wires that had a plug missing. But even then, couldn't find anything. I am going to keep looking though. Something has to be there.

 

[jpmxrider489]

Try looking for wires that were cut or short near the harness. You can contact vtechthis see if he has the plug and pigtail you can splice in. He deals with harness all the time, maybe you can ask him what plug its next to in the harness.