Preliminary Turbo Diagnose – Boost Issues
When driving a turbocharged engine vehicle and you encounter boost issues, here are a few things that you should examine first before concluding it to be turbo’s failure. Often times you would find the turbo to be fine which have wasted your time and effort in disassembling the turbocharger.
First check your intake piping see if there’s any leakage that causes low boost pressure, this normally happens especially with the connections with the intercooler because of the pressure differences and bent pipes. When part of the piping loosens or damages it will cause black smoke from the exhaust pipe. It is recommended to use clamps and silicon hose for tightening the connecting areas. On the other hand, check whether your blow-off is stuck, worn out, or if the spring isn’t durable, having one of the situations will also cause boost leakage. Make sure to check and clean your blow-off regularly.
Overboost may be the cause of malfunctioning solenoid valve, check if one of its vacuum pump connection hoses is pierced. On the other hand, lack of power supply might be due to the missing positive power supply or the wiring harness is faulty. The filters on both sides of the solenoid valve are important as they prevent dust and debris from entering and clogging solenoids. If this is not taken care of early, unstable boost may damage the turbo and engine. Some of the diaphragms in wastegates and actuators do not last long, damaged diaphragm may stop the valve from opening up properly in relieving the boost. Do check the diaphragm once per year.
After you have checked all of the abovementioned components and everything is fine, there’s a great chance that the boost issue comes from the turbo itself. If your turbo does not boost at all, in most cases the thrust bearing has already been broken due to pushing under high boosts. Its debris makes noise when contacting other metal parts so you know what’s wrong with the turbo if you can’t generate positive pressure.
There will usually be some signs for you to notice the failure of a turbo, mostly from the knocking noise it produces, or when you see oil coming out from intake pipes that leads to white smoke coming out of the exhaust, this means the bearings are damaged. Soon the wheels make wind blowing sound too, the turbo has to be repaired or replaced immediately, once it hurts the bushes on the crank it’ll be a big problem for your vehicle.