Mazda BT-50 Engine Problems
Why is my 2015 Mazda BT-50 losing power?
You can probably rule out anything like a split turbo hose as this would cause the vehicle to lose power all the time, not just after prolonged use. Modern turbo-diesels like the one in your car use a range of electronic sensors and controls to keep everything running properly. It could easily be that a sensor is sending erroneous messages to the computer. An electronic scan of the vehicle should offer some answers.
The other possibility is that the fuel system is not keeping up with the engine over time. This could be due to a blocked filter, a blocked fuel line or return line or even a fuel pump overheating. A check of the fuel system would also be in order.
What could be causing my 2009 Mazda BT-50 to misfire?
It sounds like you’ve tried pretty much everything here, but I have a few suggestions. Have you cleaned out the inlet manifold? The combination of soot and oil mist that gets recycled back through the Mazda’s engine (and a lot of modern turbo-diesels are the same) can cause all sorts of poor running conditions including surging and mis-firing. I know you said you’ve disconnected the EGR valve, but this build-up could already have occurred.
What about the fuel system? You said you’ve replaced the injectors, but have the fuel pumps been checked for flow and pressure? What about the fuel return line? Is it blocked and causing an obstruction to the fuel flow below 80km/h? What about the fuel pick-up inside the tank? A split or damaged pick-up can allow air into the system and cause all sorts of grief.
Also, this generation BT0-50 used throttle-by-wire. Many owners didn’t like the operation of the standard set-up and changed to an adjustable system that allowed them to soften (via a dial on the dashboard) the throttle action for off-road use. Has your vehicle been modified like this? Even if it hasn’t, the standard throttle set-up could be faulty and causing the problems you’re seeing.
The fact that the vehicle operates perfectly in some situations leads me to suspect an electronic or fuel supply problem. If it was a major mechanical issue such as a burned valve or a major mechanical glitch, the engine would likely not run properly at all.
Did the 2013 Mazda BT-50 come with an engine cover?
We contacted Mazda specifically on your behalf, and its response is that only some grades have an engine cover. Ones that do not are the base XT, while the XTR and GT versions do have a cover. We hope this helps.
Mazda BT-50 2011: Turbo noise?
Without being able to view it and hear it firsthand it's hard to suggest what might be wrong. It could be a bearing in the turbo, but that's only an educated guess. I would have a mechanic check it.
Mazda BT-50: Engine and powertrain light illuminated
You need to take it to a mechanic for a diagnostic check to find the cause of the problem. It sounds like it could be in the transmission; perhaps the powertrain module could be at fault.
Mazda BT-50 2009: What is the best oil to use?
You should be running a 5W-40 oil.
Mazda BT-50 2014: Cold start stalling
It won’t be a gearbox fault, and it won’t be air in the fuel. It’s happening on first starts, so look for something that’s amiss with it during the cold start phase. It’s probably not getting the required enrichment. Check the engine sensors.
Mazda BT-50 2013: Burst heater hose
It’s hard to believe there was no warning before the engine blew. The engine would not instantly overheat the moment the coolant was dumped and there would have been some signal to indicate all was not well. If Mazda are refusing to talk to you, you could take it to VCAT and make a claim.
Mazda BT-50 2014: Coolant hose to the turbo fractured
It’s certainly something that should be fixed under warranty, but it’s not something that would normally be the subject of a recall. Recalls are for issues of safety where there is a risk to life and limb.
Mazda BT-50 2017: Why is it dropping into limp mode?
With so many different causes logged on the diagnostic check you would have to think it’s something like the ECU, but it’s a hard one to diagnose. You really need to have it happen when the mechanic is there to witness it.