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      03-29-2024, 12:22 PM   #1
houiam
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Exclamation Boost spike on Bank 1 - help

Hi,

I suspect a vacuum leak is causing the turbo on bank 1 to overboost. My MHD monitor is reading 32.9 psi of boost on turbo 1 and 11.3 on turbo 2. This is coupled with the car “hunting” once in a while at idle. Where do I start my troubleshooting for the vacuum leak that’s causing the waste gate to stay closed?

Attached a picture of my MHD log showing the difference in Boost (bank 1) and boost 2 (bank 2).

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      03-29-2024, 09:39 PM   #2
SmokinJoe
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If you just put on downpipes it’s easy to get the clamps in the way or the waste gate arms if not clocked properly. If not check the lines to the waste gates then put vac too them and watch for proper function. Then do a boost leak test.
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      03-30-2024, 03:16 AM   #3
houiam
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Thanks man. Ya I just had DP’s put it! Thanks for the tip, I’ll start there.
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      04-04-2024, 07:01 PM   #4
houiam
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Quote:
Originally Posted by SmokinJoe View Post
If you just put on downpipes it’s easy to get the clamps in the way or the waste gate arms if not clocked properly. If not check the lines to the waste gates then put vac too them and watch for proper function. Then do a boost leak test.
Update - took it to my mechanic. He said the DP clamp is not in the way. He also noticed that bank 1 boost solenoid wasn’t functioning right and got a new one.

Problem continues to exist. Bank 1 turbo is still boosting to 30+ psi!! Checked with JB4 and MHD.

I do get the following fault keep coming up. MHD reads “102002 - air volume, plausibility: air volume too low” . JB4 reads “102002 - air mass, plausibly: air mass too low”. I’m not sure if this is related to my turbo 1 boosting too much. I suspect the WG is not opening obviously.

Any help identifying the problem is appreciated
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      04-04-2024, 08:24 PM   #5
JayDD007
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The wastegate should be at the "open" or lowest boost setting at its default position since vacuum being applied to them closes them. Relatively simple to check with the top heat shield removed. Simply apply vacuum to the actuators and watch them slowly close.

If I had to guess your bank 1 actuator seems to be stuck closed as 30 psi is probably its maximum output when it causes faults.

I've also seen the pressure converters send full vacuum to the wastegate and pull it closed constantly but you mentioned it's been replaced. Bank one and two could also be swapped if necessary.
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      04-06-2024, 11:15 PM   #6
houiam
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Issues resolved.

Got rid of the 102002 code by cleaning the MAF sensor on bank 1.

I decide to swap out my boost controller connections to see if the issue would move over to bank 2. But instead that fixed the overboost issue.
Thanks for your help
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