Why is the boost still insufficient after replacing the turbo on the Haval H6?
3 Answers
There are several possible reasons for low boost pressure in the H6, including exhaust pipe blockage, faulty wastegate valve, air leaks in the piping, or a damaged turbocharger. How turbocharging works: A turbocharged engine relies on a turbocharger to increase the engine's air intake. The turbocharger (Turbo) is essentially an air compressor. It uses the exhaust gases from the engine as power to drive the turbine in the turbine housing (located in the exhaust passage), which in turn drives the coaxial impeller (located in the intake passage). The impeller compresses fresh air delivered from the air filter pipe and sends it into the cylinders. As the engine speed increases, the exhaust gas flow rate and turbine speed also increase, thereby enhancing the air compression level. This results in a corresponding increase in the engine's air intake, which boosts the engine's output power. The function of turbocharging: The primary role of turbocharging is to increase the engine's air intake, thereby enhancing the engine's power and torque, making the vehicle more powerful.
As someone who frequently repairs turbocharged cars, I think if there's still insufficient boost after replacing the turbo, it's likely not the turbo itself that's the problem. Sometimes it's due to poorly connected pipes leaking during installation, or a clogged intercooler. I once saw an H6 with a stuck blow-off valve causing constant pressure loss. Also, if ECU sensors like the boost pressure sensor fail, the computer can't control properly. There are also hidden issues like cracked exhaust manifolds. If this happens right after replacement, it's best to check the installation quality, inspect all pipe connections and sensor plugs. If that doesn't help, test the exhaust backpressure. If you're not confident in your skills, it's safer to take it to a reliable repair shop for diagnosis.
I've been working on turbocharging systems for many years, and the H6 situation is quite common. First, confirm if the new turbo model is correct, as different versions match differently. Then, focus on the intake piping, as there might be cracks or loose connections causing leaks. In a case I encountered before, the wastegate behind the turbo was stuck open, and upon disassembly, the spring was found broken. Also, check for incorrect signals from the oxygen sensor or MAP sensor, which can mislead the ECU. Lastly, don't forget about the oil supply; insufficient oil to the turbo bearings can cause them to seize, preventing boost pressure from building up. It's advisable to use a diagnostic tool to read fault codes and check the data stream before proceeding with any disassembly to avoid unnecessary work.
