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boost gauge shows 0 psi at wot

I am out of solutions at this point and I'm about to go insane. I just had installed topgunz a2a kit and have leak tested 3 times now. I also

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Old 01-10-2020, 11:33 PM   #1 (permalink)
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Default boost gauge shows 0 psi at wot

I am out of solutions at this point and I'm about to go insane. I just had installed topgunz a2a kit and have leak tested 3 times now. I also tightened the supercharger belt as much as possible. The first time I found two leaks. One small one on the block off plate and another small one coming from the maf sensor. After that I ended up checking it two more times and found no additional leaks.

Seb says I'm only getting 4.5 pounds peak boost. My boost gauge that I've tried on two different vacuum lines shows 0 psi at WOT. The only part I didnt check for leaks is the supercharger itself.

Also mineral oil smells like ****!

Last edited by DUSHER; 01-10-2020 at 11:36 PM.
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Old 01-11-2020, 03:10 AM   #2 (permalink)
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How are you testing for boost leak?
Here is how I tested https://www.youtube.com/watch?v=-7ZPmLl_7xI

Are you saying the block off plate on the manifold was leaking? How did you test that?

0 PSI at WOT is actually not necessarily a problem with a centrifugal SC, it depends on at what RPM this is happeninig. Boost will = 0 at WOT below a certain RPM.

Does your boost gauge EVER see boost? Seb sees 4.5 which is coming from the MAP sensor in the manifold. Your gauge is being fed from a vacuum line coming off the manifold. If Seb see's boost, but your gauge never does, that might be a pinched/torn vacuum line.

Not sure why he only sees 4.5 psi though. Maybe your manifold not sealed, but not sure how you tested that it's OK.
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Old 01-11-2020, 10:10 AM   #3 (permalink)
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Quote:
Are you saying the block off plate on the manifold was leaking? How did you test that?
yes. Where the manifold cooler once was. I work at a dealership with two different smoke leak testers.

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Here is how I tested https://www.youtube.com/watch?v=-7ZPmLl_7xI
What exactly am I watching here? Is this showing the car has no leaks?

Quote:
Does your boost gauge EVER see boost? Seb sees 4.5 which is coming from the MAP sensor in the manifold. Your gauge is being fed from a vacuum line coming off the manifold. If Seb see's boost, but your gauge never does, that might be a pinched/torn vacuum line.
yes it does. At idle it shows 24 and when I give it about 25-75% throttle I usually see 8. As far as the type of vacuum line that I'm using, its just a regular air line. I made sure there were no kinks in it. I got the gauge for free since it was used so I'm not 100% sure if its faulty.

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Not sure why he only sees 4.5 psi though. Maybe your manifold not sealed, but not sure how you tested that it's OK.
Like I said up above I tried two different testers. One produced more pressure than the other. I also tried to hook it up to the pipe that connects to the supercharger, T'd it off of the BOV line, and the last time off of the port on the back of the intake manifold

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Old 01-11-2020, 01:18 PM   #4 (permalink)
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Ok, there is a lot of info and statements here that are conflicting and confusing. And, and I’m not sure what your main complaint is. Instead of pointing out all of these here and asking a bunch of questions, can you send me the log you sent Seb? PM me if you want.
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Old 01-12-2020, 01:33 PM   #5 (permalink)
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You say that at idle it shows 24 and at medium throttle range shows 8. This sounds like vacuum? Maybe in inches H2O or Hg? Even at WOT, you won't see any manifold pressure until you're above maybe 3k RPM (off the cuff, I'm sorry if not exactly accurate).

My pressure meter is T'd off the line that goes to my BOV and fuel pressure regulator.
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Old 01-12-2020, 06:26 PM   #6 (permalink)
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Originally Posted by turtle64b View Post
You say that at idle it shows 24 and at medium throttle range shows 8. This sounds like vacuum? Maybe in inches H2O or Hg? Even at WOT, you won't see any manifold pressure until you're above maybe 3k RPM (off the cuff, I'm sorry if not exactly accurate).

My pressure meter is T'd off the line that goes to my BOV and fuel pressure regulator.
I had my info all ****** up. It was at -24 at idle. I found out that the gauge was uncalibrated/broken. When the gauge was uplugged from the vacuum line it showed -6. I have a new gauge and I'm going to check it. Thanks for the help
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Old 01-12-2020, 06:36 PM   #7 (permalink)
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Originally Posted by DUSHER View Post
I had my info all ****** up. It was at -24 at idle. I found out that the gauge was uncalibrated/broken. When the gauge was uplugged from the vacuum line it showed -6. I have a new gauge and I'm going to check it. Thanks for the help
Hell yeah, glad it is an easy fix. I've chased all kinds of leaks on all kinds of cars and they're never fun...
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Old 01-14-2020, 01:34 PM   #8 (permalink)
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How would that faulty gauge change the fact that Seb was only seeing 4.5 from the ECU?
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