Huge boost leak that I can't even find!

[JwUoNoG]

I have a boost leak, I listened, and it sounds like it's near my throttle body and intake manifold area (specifically under all the fuel stuff). I looked everywhere, I put a piece of paper in the alleged location of the boost leak, no luck, I sprayed soapy water everywhere, no luck.

Is it possible my intake manifold is cracked, or has a hole in it? I don't see where the leak could be.

Please respond, especially if you've ever had a boost leak in this area.

 

[xcelr8n]

probably youre throttle body shaft seals..

 

[Defiant]

Put a 3" piece of vacuum tubing to your ear and start poking around with the other end. When you hear an F-16, you've found the leak.

 

[PaleDSM]

Defiant's idea is a good one. It works great.


Did you open and close the tb while you were listening? That usually gives away the tb seals.

 

[oldman]

It could be your injectors.

 

[Tallen]

If it is not a TB, injector seal, vac hose, or bad intake manifold gasket, its probably just air leaking through the valves...

 

[oldman]

Bring it to TDC and see if you still have the leak.

 

[JwUoNoG]

Thanks for all the help so far guys. I'll try to do all that when I have time. I'm kind of dreading it, my UICP sits in a way that makes the intake hard to reach, but oh well.

Also, when my friend pressurized it, it didn't even go above 1 psi. I dunno if that would help narrow it down or not, I just thought I'd throw it in.

 

[oldman]

1 psi? that is bad. Fix whatever you find, you'll probably find more later as you're able to increase the pressure. TDC will allow you to focus on the anything before the intake gasket. Also, disable the pvc hose and the boost source to the mbc. Good luck.

 

[firehawk]

sweet, someone else may be having the same problem as me. Well, my car is getting about the same amount of boost, (a little more now) but this weekend i was looking for a leak and eventually found it, i heard it in the same area as you described. From what im told it doesnt really affect boost but i dont know how. Anyways, underneath the intake manifold on either side if you reach in you should feel 4 valves, (1 or 2 of them may have a hose connecting them) once you find that nozzle, then you found your problem. Where to go from there, i dont kno, as im new to this and i dont know what should be connected to those nozzles and why there are 8 total and i only have like 3 lines connected.

 

[JwUoNoG]

sweet, someone else may be having the same problem as me. Well, my car is getting about the same amount of boost, (a little more now) but this weekend i was looking for a leak and eventually found it, i heard it in the same area as you described. From what im told it doesnt really affect boost but i dont know how. Anyways, underneath the intake manifold on either side if you reach in you should feel 4 valves, (1 or 2 of them may have a hose connecting them) once you find that nozzle, then you found your problem. Where to go from there, i dont kno, as im new to this and i dont know what should be connected to those nozzles and why there are 8 total and i only have like 3 lines connected.

I'm not sure if we have the same problem. I can still hit normal amounts of boost in most gears, but it definitely isn't pulling like it did. I can't hit full boost in 5th gear, I'm not sure if that's accountable to my leak.

Also, it feels like the leak is more "present" under partial throttle. As soon as it hits 7 lbs, it starts to hiss loudly, it breaks up and stumbles, and stops accelerating.

Is that what you have?

 

[firehawk]

oh, no i guess we dont have the same prob, but hopefully you get yours worked out....i got mine...finally

 

[JwUoNoG]

Whatever mine is, it's bad. Just now, I couldn't keep up with a stock Civic EX.

I felt so stupid.

 

[na_turbotalon]

Anyways, underneath the intake manifold on either side if you reach in you should feel 4 valves, (1 or 2 of them may have a hose connecting them) once you find that nozzle, then you found your problem. Where to go from there, i dont kno, as im new to this and i dont know what should be connected to those nozzles and why there are 8 total and i only have like 3 lines connected.

I'm not sure what "valves" you are talking about. All I can think of are the hard lines that are attached to the intake manifold stay. All they do is connect a rubber vaccum line from one side of the engine to a rubber vaccum line on the other side of the engine. On most cars they won't all be used, dpends on the options and emissions junk the car has. But yes there could be a leak there. Start eliminating vaccum lines in your engine bay to minimize these problems in the future.

 

[JwUoNoG]

I never opened up my TB when I did my boost leak test... does that mean that the leak is somewhere before it?

 

[marcmsj]

I never opened up my TB when I did my boost leak test... does that mean that the leak is somewhere before it?

i have a boost leak too... mines not as bad though, i can hold about 13psi but no more. maybe we could get together sometime and help each other out..

i'm tom's friend by the way at carmax. i think you know him.

 

[JwUoNoG]

i have a boost leak too... mines not as bad though, i can hold about 13psi but no more. maybe we could get together sometime and help each other out..

i'm tom's friend by the way at carmax. i think you know him.

Yep. I saw Tom a week or so ago actually.

 

[marcmsj]

well, i found my boost leak.

can't believe it didn't occur to me before. apprently when i put my new turbo in, i forgot to reconnect the vaccum line from the manifold to the BOV... smart one :thumbdown

that's what happens when you work on your car when you're dead tired.

anyway, car running like a champ now and boostin 18psi