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2026. 6. 30. 작업

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Troubleshooting low boost pressure

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My first thought, based on the boost dropping as you rev the engine before the turbo was replaced is that there is an inlet restriction. Something like a dirty air filter or damaged inlet piping. That could also cause the replacement turbo to fail to deliver full boost. One quick check for this would be to remove the compressor inlet pipe from the turbocharger. That would also bypass any sensors upstream of the compressor – for instance a mass air flow (MAF) sensor if the engine has one, so it is possible that the ECU could set codes, or put the engine in a reduced output (limp) mode as a result of the loss of the sensor. As rpmerf mentioned a restriction on exhaust flow could also cause low boost. This could be caused by a blocked catalytic converter. It can be a real pain to open up the exhaust experimentally, but if the car has an O2 sensor or some other port in the exhaust system you can measure the exhaust back pressure to get a feel for how restricted the flow is. Ideally you'd c