Boost Leak Test Problem

blackdemon · Oct 3, 2009, 07:47 PM

My buddy evodan did a boost leak test on my car yesterday. He made sure the motor was at TDC. When he started to put air through the turbo we would here the air comming out of the exhaust. And the boost gauge would not go past 2psi. What can be the cause of this. Any help is apreciated. Thank you in advance.

evodan2004 · Oct 3, 2009, 07:51 PM

when doing the test i had 120/140psi in the air line. anyone who uses a compressor knows it wont inject 140psi but it helps to build pressure faster. normally it takes me about 15 seconds to build up 30psi on my car.

leo's car would not touch past 2 to 4 psi. and it all seemed to be coming out of the exhaust. there was a leak at the TB seals but that wont loose 26psi ''the goal'' we lost. there seemed to be no other leaks but again it was all being poored out the exhaust.

am i missing something as i never had this issue before on any other car.

TommiM · Oct 3, 2009, 07:58 PM

Damn, I was just gonna post a thread about a boost leak issue Im having. At around 7 psi I hear a weird noise, like something opening, from under the car near the turbo.Could it be the wastegate opening? Bad turbo seals? Its just this weird groaning noise. I have stock intake, stock DV, stock exhaust. Never noticed it before when doing a boost leak test.

evodan2004 · Oct 3, 2009, 08:02 PM

Quote:

Originally Posted by TommiM

Damn, I was just gonna post a thread about a boost leak issue Im having. At around 7 psi I hear a weird noise, like something opening, from under the car near the turbo.Could it be the wastegate opening? Bad turbo seals? Its just this weird groaning noise. I have stock intake, stock DV, stock exhaust. Never noticed it before when doing a boost leak test.

normally on a MBC car ''like leo's you will here the MBC open up. i never had to block off the waste gate lines. his car you sit buy the tail pipe and you can here it all pooring out the exhaust. plus at TDC the valves should be closed which would stop the air from going into the exhaust side of things no???

TommiM · Oct 3, 2009, 08:16 PM

Quote:

Originally Posted by evodan2004

normally on a MBC car ''like leo's you will here the MBC open up. i never had to block off the waste gate lines. his car you sit buy the tail pipe and you can here it all pooring out the exhaust. plus at TDC the valves should be closed which would stop the air from going into the exhaust side of things no???

TDC does not necessarily mean all 16 valves are gonna be closed at the same time, fyi.

evodan2004 · Oct 3, 2009, 08:19 PM

Quote:

Originally Posted by TommiM

TDC does not necessarily mean all 16 valves are gonna be closed at the same time, fyi.

i know that. but i normally dont do this to begin with. but i did on his car as i was looking for an answer the the problem.

TommiM · Oct 3, 2009, 08:28 PM

Quote:

Originally Posted by evodan2004

i know that. but i normally dont do this to begin with. but i did on his car as i was looking for an answer the the problem.

If I remember someone posting a similar issue. There was a vacuum line underneath the TB that was disconnected partly. Check all the vacuum lines on your intake manifold and tb.
I wanna say it was EGR???

evodan2004 · Oct 3, 2009, 08:34 PM

Quote:

Originally Posted by TommiM

If I remember someone posting a similar issue. There was a vacuum line underneath the TB that was disconnected partly. Check all the vacuum lines on your intake manifold and tb.
I wanna say it was EGR???

hum. i did not notice a leak or sound from there but still it should build up more pressure then 4 psi. more like 15 but drop hard and fast with a vac line off.

we will look into this though. thank you

blackdemon · Oct 4, 2009, 03:27 AM

I'll check the vac lines asap. I'll be doing a leak down test with mr dan as well just to make sure everything is ok.

LV///R · Oct 4, 2009, 09:24 AM

Crazy,

I didn't even see your thread. I did a boost leak test as well yesterday and had the SAME exact issue.

To the OP:

Do you have any EGR CEL Codes?

I have had an EGR (insufficient flow) code for some time. Checked the lines about a year ago, even replaced the EGR valve, yet nothing helped. Car drove fine, so I just left it as is. I'm wondering if this has something to do with us hearing the compressed air come out the exhaust???

I'm doing a compression test today to see what I find out as well.

Goodluck, and keep us posted what you find out.

blackdemon · Oct 4, 2009, 08:23 PM

Quote:

Originally Posted by LV///R

Crazy,

I didn't even see your thread. I did a boost leak test as well yesterday and had the SAME exact issue.

To the OP:

Do you have any EGR CEL Codes?

I have had an EGR (insufficient flow) code for some time. Checked the lines about a year ago, even replaced the EGR valve, yet nothing helped. Car drove fine, so I just left it as is. I'm wondering if this has something to do with us hearing the compressed air come out the exhaust???

I'm doing a compression test today to see what I find out as well.

Goodluck, and keep us posted what you find out.

I have no check engine light at all. We will be doing a comp and oil leak down test soon.

haseeb · Oct 4, 2009, 11:13 PM

not even a sigal solid answer for the problem he is facing ..
i wana know this also ...
thanx

Evokid03 · Oct 4, 2009, 11:17 PM

I have the same issue, I did a compression test and leak down test and car checked out fine

Anyone have n answer to this????

GST Motorsports · Oct 4, 2009, 11:22 PM

EGR line is most likely off the EGR

It's under the throttle body, on the #1 intake runner. If the vac line is of you won't be able to pressurize with boost leak tester.

I've had it happen many many many times.

- Bryan

Evokid03 · Oct 4, 2009, 11:24 PM

Ill double check tomoro, also what confuses me is before i was able to do a boost leak test no problem.. but after i changed to a forge wga and synapse bov (recirculated) the problem occured