1G Cracked BOV

[91lzer]

I was running some errands in the 1g the other day and my idle wouldn’t go below 1400RPM. So I decided to do a boost leak test and everything was not okay.

I found out that my BOV has a hole in it some how. I’m also leaking from the clamp in the middle of my turbo (probably not tight) and I’m missing my BISS. I’m confused about the hole though?

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[TerminalTalon]

It looks like someone pried on it and o er time it developed a leak.

 

[91lzer]

It looks like someone pried on it and o er time it developed a leak.

must have been me. I don't remember every prying on it but maybe i dropped it.

 

[TerminalTalon]

You could probably get away with jbweld after getting it to bare metal.

 

[DSMPT]

my idle wouldn’t go below 1400RPM

I’m missing my BISS

This is the cause why the idle wouldn't go below 1400rpm.
That crack on BOV would cause boost leak but not vacuum leak. Missing BISS, yes you would have a huge vacuum leak and you would have a high idle issue if you meant that you are physically missing the BISS.

 

[91lzer]

This is the cause why the idle wouldn't go below 1400rpm.
That crack on BOV would cause boost leak but not vacuum leak. Missing BISS, yes you would have a huge vacuum leak and you would have a high idle issue if you meant that you are physically missing the BISS.

Now I’m not sure what the inside of the BISS hole is supposed to look like, but mine has a plate about 1cm down and there are no threads. I tried to push down that plate with a screwdriver but it wouldn’t move. Do you know what the inside of the hole is supposed to look like? I’d post a pic but my car is about an hour away. And it wasn’t leaking very much either. It it possible that someone shoved a plug into the hole?

 

[DSMPT]

Now I’m not sure what the inside of the BISS hole is supposed to look like, but mine has a plate about 1cm down and there are no threads. I tried to push down that plate with a screwdriver but it wouldn’t move. Do you know what the inside of the hole is supposed to look like? I’d post a pic but my car is about an hour away. And it wasn’t leaking very much either. It it possible that someone shoved a plug into the hole?

A plate? You are talking about the BISS screw on throttle body, correct? If so, perhaps you have a metal BISS screw, and the head got stripped and cause it stuck, or someone blocked off before for some reason? We need to see a pic.

The BISS screw and the hole are threaded and the BISS screw has an o-ring seal. The upper side of the BISS hole doesn't have screw threads and you don't see the screw threads if the BISS is in there. Tip side of the BISS screw, there is an air passage that bypasses the throttle plate and the BISS screw is adjusting the amount of air that bypass the throttle plate. So even if you had no leak from the BISS o-ring when you ran the boost leak test, if the BISS screw position is set improperly to open the bypass more than it should, the engine would suck more air through there and the engine speed would get higher. It's like the same effect as when you have the throttle plate more open than it should by improper adjustment. So if you have never adjusted the throttle body, you should do it. It's always required to obtain the stable idle.

Here some pics.
1st pic, how it looks like.
2nd pic, inside the BISS hole. You see screw threads.
3rd pic, bypass hole pre throttle plate.
4th pic, bypass hole post throttle plate with the bypass open. You see the light pass through the bypass hole from pre throttle plate.
5th pic, bypass hole post throttle plate with BISS fully bottomed. You see no light pass through.

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[91lzer]

A plate? You are talking about the BISS screw on throttle body, correct? If so, perhaps you have a metal BISS screw, and the head got stripped and cause it stuck, or someone blocked off before for some reason? We need to see a pic.

The BISS screw and the hole are threaded and the BISS screw has an o-ring seal. The upper side of the BISS hole doesn't have screw threads and you don't see the screw threads if the BISS is in there. Tip side of the BISS screw, there is an air passage that bypasses the throttle plate and the BISS screw is adjusting the amount of air that bypass the throttle plate. So even if you had no leak from the BISS o-ring when you ran the boost leak test, if the BISS screw position is set improperly to open the bypass more than it should, the engine would suck more air through there and the engine speed would get higher. It's like the same effect as when you have the throttle plate more open than it should by improper adjustment. So if you have never adjusted the throttle body, you should do it. It's always required to obtain the stable idle.

Here some pics.
1st pic, how it looks like.
2nd pic, inside the BISS hole. You see screw threads.
3rd pic, bypass hole pre throttle plate.
4th pic, bypass hole post throttle plate with the bypass open. You see the light pass through the bypass hole from pre throttle plate.
5th pic, bypass hole post throttle plate with BISS fully bottomed. You see no light pass through.

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Thanks for the pictures man, i never thought to look from the inside of the TB. at first i thought that the head might be stripped out, but the top looks uniformly flat. almost like the head was ground off before somehow being inserted. i'll have to go take a look sometime but my car is over an hour away for the winter so id have to make some time. i'll update when i can. thanks.