Mazda BT-50 Diesel Problems

What could be causing my 2009 Mazda BT-50 to misfire?

Answered by CarsGuide 11 Sep 2020

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.

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Is the 2007 Nissan Navara a good choice?

Answered by CarsGuide 11 Sep 2020

For a few years from 2005, Nissan sold two types of Navaras in Australia - the all-new big D40 series and the old D22 that dated back from the latter 1990s. 

If you want an inexpensive, compact and hard-wearing truck that's reliable but not very refined nor comfortable, the old D22 is it. Its 3.0L turbo-diesel has proven strong and reliable in this application and the Nissan has a reputation for being as tough as nails.

The larger and newer D40, meanwhile, is the much better choice if space, safety and refinement are priorities, and remained a class-leading proposition right up until the current-generation Ford Ranger, Mazda BT-50 and Volkswagen Amarok all moved the pick-up truck game on in 2011. The Spanish-built ST-X is the choice grade, especially in turbo-diesel and 4x4 guise.

The Navara is considered a reliable and dependable truck, but many are also workhorses that lead tough lives and are often neglected or mistreated. If you're after one, please consider having it checked out first by an experienced mechanic.

Known issues include fuel-injection failure, roof rust, premature clutch wear in manual  models, electronics issues, turbo-charger failures and sagging rear springs.

Such problems can apply to any similar truck, so don't be too put off by the D40 Navara. It's a firm used-truck favourite for good reason.

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Mazda BT-50 2013: Does blanking off the EGR valve harm the engine?

Answered by CarsGuide 4 May 2020

You’ll almost certainly cause the dashboard to present you with a `check engine’ warning light, Brett, as blocking off the Exhaust Gas Recirculation (EGR) valve is an intrinsic part of the vehicle’s emission controls. Having the vehicle go into limp-home mode is a very real possibility as well.

But perhaps more financially damaging would be the consequences of being caught driving the vehicle with a blocked-off EGR. The government takes a very dim view of anybody disabling any part of a car’s emission controls and the fines for doing so can be huge.

However, I know this is a real issue for many owners of modern turbo-diesels. The problem is that soot from the exhaust gas is mixed with oily fumes from the crankcase and then ingested by the engine as part of keeping emissions down. But the mixture of oil and soot can form a black gunge that can block the intake system. Really, though, blocking the EGR is a fairly clumsy way of getting around this. My advice would be to fit an oil separator which should keep the oily mist from the crankcase ventilation out of the equation.

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Mazda BT-50 2013: Motor problems

Answered by CarsGuide 7 Jun 2019

Is it something new, or has it always been this way? I’m wondering if you’re just feeling the diesel engine, which works best at lower engine speeds. Rev it too high and you’ll lose the effect of the diesel torque. It could simply be that, or it could be an electronic problem. Have a mechanic run a diagnostic check on it to see if there is a problem.


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Mazda BT-50 2017: Why is it dropping into limp mode?

Answered by CarsGuide 8 Jan 2018

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.

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Mazda BT-50: Losing power

Answered by CarsGuide 16 Sep 2017

No. That’s an odd one and needs investigation to determine what’s gone wrong. I’d suggest consulting a diesel engine specialist.

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Best diesel ute for towing a horse float?

Answered by CarsGuide 14 Oct 2016

The Amarok is rated to tow 3000 kg, which would make it marginal for your needs given that you want to tow around three tonnes. The Ranger and BT-50 are rated at 3500 kg, which would make them more suitable for you. The Ranger and the BT-50 are the same vehicle, it's only the features that separate them. For me, of those you list the Mazda is the best value-for-money.

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Mazda BT-50 2016: Rattling when cold started

Answered by CarsGuide 20 May 2016

Mazda’s advice is probably on the money. Worn injectors are a common cause of a rattle on cold starts on common-rail diesel engines like you describe.

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Isuzu D-Max: Is it a good single-cab turbodiesel ute?

Answered by CarsGuide 15 Dec 2014

It's OK but the Ford Ranger and Mazda BT-50 are better. The Mazda gets The Tick based on lower prices for better value.

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Towing with a dual-cab ute?

Answered by CarsGuide 24 Nov 2014

It's too early for a reliability read on classy utes such as the Ford Ranger/Mazda BT50 and VW Amarok, which with their lusty turbo diesels are great for heavy work.

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