WILL COMMON-RAIL GO THE DIESEL DISTANCE?
Our major investigation into the common-rail diesel failure epidemic is sure to ruffle a few feathers
WORDS BY STEVE COLLINS, PHOTOGRAPHY BY CARAVAN AND MOTORHOME
Twice the power – twice as many kilometres out of a tank – twice as likely to blow up. That’s what many are saying about the new breed of common-rail diesel engines. Are modern diesels becoming like air craft? Are they now too complicated and at the risk of falling out of the sky if even the smallest issue arises?
There’s no hiding that there are some common-rail engines out there – extremely popular ones – with some pretty serious issues. Sure, there’s a long list of mechanical diesels that’ve had their share of dramas too, but experts are seeing an alarming number of modern common-rails fail, racking up some hefty repair bills along the way. Think about it – a set of big-ends on a 1HD-T 80 Series costs what, $400? A set of dead injectors on a new commonrail can cost upwards of $3000. Sure, they pull like a freight train, have an incredible towing ability and return economy figures that’d leave any mechanic diesel for dead, but what good is any of that if it leaves you stranded in the middle of the Simmo?
So here’s the question, is common-rail injection the devil it’s made out to be, or can things be done to a common-rail 4WD to make them as reliable as any? People said coil springs were the end of 4WDs when they started replacing leaves. Everyone’s always worried about new technology lasting, but this article’s going to sort out, once and for all, whether it’s fact or fiction.
This time we’ve teamed up with five of the country’s leading diesel experts to help arm you with the cold, hard facts. We’ve cut through the hype so you can see just how easy it is to safe guard your investment and save $$$ in the process. If there’s one thing that could save you serious coin this year – it’s this right here!
THE EXPERTS!
There are few more qualified in common-rail diesel repairs and upgrades than our panel of experts
BERRIMA DIESEL
Andrew Leimroth
Andrew’s the pinnacle of small-town ‘service with a smile’, and one of the most trustworthy blokes we know. Andrew boasts 65 years of combined industry experience he shares with his father, Reinhard Leimroth. The man behind DP Chip; Andrew specialises in all aspects of 4WD diesel fuel injection including injector servicing, fuel pumps, turbocharging, exhaust packages, dyno tuning, diagnostic testing and a whole heap more.
DENCO DIESEL
Scott Wood
Scott’s been in the diesel game longer than most. He’s been with Denco Diesel for more than 30 years and specialises in all things commonrail. Denco have made a name for themselves as specialists in diesel fuel injection and turbocharger systems, and are credited as a premium service dealer for Denso, and a Bosch diesel centre.
MTQ ENGINE SYSTEMS
Tony Martin
Tony’s the Brand Manager at MTQ’s Toowoomba service center, and he’s also responsible for training their national team of technicians. That in itself is no easy feat, because MTQ is one of Australia’s largest diesel fuel injection and turbocharger aftermarket sales and service providers, which means, if there’s a problem with a diesel tow rig getting around or an upgrade worth doing, Tony knows about it. Tony’s been dyno tuning diesel engines for 14 years now, and is largely behind the development of the Rapid performance module.
BAILEYS DIESEL GROUP
Matt Bailey
Matt Bailey from Baileys Diesel Group has gone where few dare to tread, challenging industry heavyweights to help deliver you better competition and pricing. We’re talking about a team that engineers and builds millions of dollars worth of specialist machinery just because it’s going to get a better result (they’ve got 5 patented diesel test benches you just won’t find anywhere else in the world). Matt and his team have pioneered common-rail injector blue-printing – which is similar to rebuilding – only they give it the Baileys upgrade and whack on a warranty that’ll beat any OEM manufacturer. More on that later in the article.
OUTBACK TOURING VETERAN
Dave Cox
Here’s a bloke who needs no introduction. You all know him by now as the king of the western side of the Simpson desert. But he’s also one of the vehicle recovery operators for the surrounding desert areas, and so he sees firsthand what goes wrong with modern 4WDs in the outback. He’s also a fuel retailer and he uses a new CRD LandCruiser as his recovery vehicle, so there are few more qualified to weigh in on the common-rail debate than Dave.
HOW COMMON-RAIL DIESELS WORK
To understand what goes wrong, you first need to know what makes them tick
• 120 years ago, Rudolf Diesel invented the first ever compression-ignition engine
• In 1995, Denso offered the first commercial common-rail diesel fuel injection system
• Bosch followed suit in 1997
• In the mid-2000s common-rail technology hit Australian shores, bringing with it a wave of powerful, efficient and quiet ‘oilers’
COMMON-RAIL TECHNOLOGY
Common-Rail Diesel (CRD) engines themselves are essentially the same as any modern piston engine. Where common-rails differ is that the injector pump supplies fuel to one fuel rail common to all cylinders (hence the name common-rail), as opposed to generating pressure individually for each injector like older mechanically injected diesels. So in a sense, a CRD fuel system is more like to an EFI petrol engine than it is a traditional diesel.
The injector pump continually charges this ‘common rail’ with high pressure fuel. The injectors are connected to the fuel rail via high pressure lines, but instead of fuel pressure itself opening the injector like a mechanically injected diesel, the Engine Control Unit (ECU) controls when and how long the injector is opened by the use of an electronic solenoid inside the top of each injector. The ECU can also vary fuel pressure, timing and boost pressure, depending on the engine’s load, via a handful of pressure sensors and regulating valves.
THE SECRET TO A POWERFUL & FUEL EFFICIENT ENGINE
The secret is a more efficient fuel burn that high fuel pressures allow. Higher pressure means more fuel can be injected in a shorter period of time, even at high RPM. High fuel pressures also mean better fuel atomisation with better and more precise fuel metering. These pressures can be as high as 40,000psi in a common-rail, where older mechanically injected diesels were running fuel pressures of only a few thousand PSI. Running such high pressures also enables a CRD to utilise pulse injection, where the ECU injects multiple short bursts of fuel (most commonly 3-4 times per rotation, but can be as high as 5), rather than one single squirt of fuel like in older mechanical diesels. This injection methods means the fuel delivery is more precise, the burn is smoother, a lot more controlled and sustained over a larger portion of the pistons power stroke. It also helps to remove traditional diesel ‘knock’ – resulting in a very attractive engine package for consumers.
WHY THE HIGH PRICE TAG?
Matt Bailey, Baileys Diesel Group
“Two things cause high repair costs – lack of competition in the market and a lack of knowledge by repairers. Competition in the market will come in time, because at the end of the day the technology is so new. And when it does, prices will start to drop.
The second biggest problem is lack of knowledge in the industry, or ill-equipped mechanics who just don’t know what they’re dealing with. Too many rely on fault codes to narrow down on a problem and simple ‘repair by replacement’ which ends up costing you more.
Before we invested millions of dollars in specialist equipment, no one in the country was rebuilding common-rail injectors. They said it couldn’t be done. But we knew injector rebuilding was ‘the done thing’ in Europe, and in the two years since our injector reconditioning project began, we’ve successfully rebuilt every 4WD common-rail diesel injector in Australia to a higher spec than factory. We offer a longer warranty than OEM type of replacement parts.
In the last 12 months alone we have rebuilt over 10,000 injectors. We also do this at a fraction of the price of an OEM part – for instance, we’re able to offer blueprinted D-4D HiLux injectors for $325 with a 3 year warranty.”
ARE THEY REALLY AS ‘HIGHLY STRUNG’ AS THEY’RE MADE OUT TO BE?
Scott Wood, Denco Diesel
“With improvements in metal composition and engine design, we see no issues with CRD longevity, but it must be understood that engines are being designed to last for a given period. As engines wear, emissions are affected and a common-rail fuel system can compensate to a degree for certain conditions.
CRD engines are running up to 30psi of turbo boost pressure, but most 4WD applications are operating between 12-20psi. The engines are designed with this in mind and have relatively no issues unless modifications are performed that effect boost pressure outside of the engine’s capacity. For instance, increasing boost can cause the turbocharger to go into an over-speed situation and result in failure due to the physical forces applied to the compressor and turbine wheels.”
WHAT ARE THEIR DOWNSIDES?
Tony Martin, MTQ Engine Systems
“Common-rail diesels have many sensors which can fail and are more expensive to repair. The systems that operate the vehicle are very complex, and difficult to diagnose and repair if you’re in the middle of nowhere. It is not so much the engine that is complex, it’s all of the extra componentry that is required to make the vehicles comply with emissions regulations. Common-rail fuel systems also require very clean fuel of a very high quality for the system to last.”
MOST PROBLEMATIC ENGINES
What engines are undergoing repairs most often, and why?
Now look, we’ve got to take a second here to point out that every engine, at some point, experiences dramas. Search the word ‘recall’ online and you’ll see every manufacturer experiences issues. So when it comes to this sort of thing, knowledge is king. And as a Caravan and Motorhome reader, we’re giving you the knowledge of what goes wrong so you know what to look for, how to fix it, and how not to get ripped off in the process.
THE ENGINES WE FIX THE MOST
BERRIMA DIESEL
Andrew Leimroth
3.0L ZD30 NISSAN PATROL
“The motors themselves seem quite durable these days, but it’s still experiencing ancillary issues (leaking manifold gaskets). It would appear to be a good choice as long as you don’t intend towing heavy loads meaning the engine will be under full power all the time.”
3.0L D-4D TOYOTA 1KD-FTV PRADO/HILUX
“With the number of injector issues that owners are experiencing with this motor, it’s starting to make the ZD30 Patrol seem reliable. We had 150 emails within a few days from owners with problems after we ran a recent Facebook awareness post about the ongoing issues. Coincidentally a few months later Toyota ‘quietly’ recalled them, so we hear.”
BAILEYS DIESEL GROUP
Matt Bailey
2.5L YD25 NISSAN NAVARA
“EGR valves literally fall apart on these motors. You’d swear the engine had failed because it starts bellowing white smoke, but really all that’s happening is the exhaust gas is being pumped straight into the intake, suffocating the combustion.”
4.5L 1VD-FTV TOYOTA LANDCRUISER
“It’s not worryingly common, but we have seen a number of fuel tanks rusting out, even with no evidence of water contamination. It’s very unusual. This then goes through to the fuel system and causes damage.”
MTQ ENGINE SYSTEMS
Tony Martin
“All modern common-rail 4WDs have their own special problems. Some can be overcome and rectified easily, some are more difficult.”
3.2L FORD RANGER MAZDA BT50
“These are still a very new system and being a Peizo injection system, they are very sensitive. Fitting aftermarket accessories can cause you grief due to voltage changes. In this engine, the injectors are separated from the oiling system. If they burn out the seal they blow soot up the body of the injector and not into the engine oil.”
WHAT EXACTLY GOES WRONG WITH THEM, AND WHY?
What’s causing three of the most common CRD failures around?
3.0L NISSAN PATROL ZD30
The ZD30 has a reputation for cracking pistons. Unfortunately, there is not just one cause, it’s a combination of lubrication issues, sudden turbo and cylinder pressure fluctuations caused by either a boost leak, a faulty MAF or boost sensor, and even a build-up of carbon on the inlet valve stem and port areas. It’s a recipe for disaster in anyone’s book.
Tell-tale signs of engine failure are coolant blowing out of the radiator cores or expansion tank, poor idling, lack of power and large chugging plumes of white smoke from the exhaust.
The trick to preventing the problem is to use low-ash engine oil, ensure the air filter is kept clean, ensure the air flow meter, boost sensor and intercooler are working correctly and not leaking or contaminated. Fit an oil catch can to prevent oil vapours contaminating the air flow meter. Also remove and clean the EGR circuit regularly – it’s known to contribute to the problems.
3.0L TOYOTA HILUX/PRADO D-4D 1KD-FTV
Cold knocking can be a problem with this motor, which is caused by the injector spindle sticking open when cold. This can lead to that cylinder being over fuelled which makes it run hot, and if left unchecked, will ultimately crack a piston.
There’s also been a run of leaking injector seals on this motor. These seals separate the combustion gases from the oil, and if they leak, can lead to excessive carbon (soot) contamination in the oil, which owners may not even notice. It may blow smoke on start up under certain conditions, e.g. if you park over night with the nose down. But other than that it can be hard to pick. Replacing the seals is the only fix, but regular 5,000km servicing will also go a long way to preventing engine damage.
4.5L 1VD-FTV TOYOTA LANDCRUISER
There are largely exaggerated stories that the 1VD-FTV has an oil usage problem. Simple truth is, it’s not uncommon for any engine to use oil for up to the first 30,000km or so – it’s not a ‘fault’ – it just takes time for components like seals and piston rings to bed in completely. It can be made worse in the Toyota V8 for two reasons.
The 1VD-FTV requires very specific C3 grade 5W-30 fully synthetic engine oil, and if you deviate from this grade of oil the engine will start to use oil. They also get pushed harder than other engines by their owners. As an agricultural vehicle, they’re often tasked with towing heavy loads or lugging tray loads of gear, so a little blow-by is to be expected until everything has settled.
THE MOST COMMON CAUSE OF FUEL CONTAMINATION IS NOT A SERVO
Dave Cox, Outback Touring Veteran
“On a number of occasions I’ve been accused of selling contaminated diesel that has resulted in damage to a CRD injection system. This is very difficult to prove and was unlikely to have been the case. With the amount of vehicles that we refuel, including ours, a contamination would not be restricted to just one incident, there would be more.
The source of contamination is often due to a careless owner. Jerry cans are the most common source of fuel contamination, with steel ones at the top of that list. Check them thoroughly and clean them if required prior to use, there may be rust, algae, or dirt in them.
The fuel filler is the next culprit, especially on a ute. Try to clean as much dirt away prior to removing the cap”
WHAT’S THE BIGGEST KILLER OF ANY COMMON-RAIL DIESEL?
Matt Bailey, Baileys Diesel Group
“It’s simple, fuel contamination and poor servicing. Because the tolerances in a common-rail fuel system are extremely tight, any contamination is going to cause damage. Once scoring occurs in the pump or injectors, it’s too late – the damage is done. And preventing it is often as simple as installing a quality secondary filter and only filling up at a reputable service station.”
THE MOST RELIABLE COMMON-RAIL MOTORS ON THE MARKET
What are the toughest common-rail motors out there? The ones that rarely break down, respond best to performance upgrades and are rather forgiving
BERRIMA DIESEL
Andrew Leimroth
“Hard to nut it down as they all have a variety of issues.”
4.5L V8 TOYOTA LANDCRUISER (DENSO SYSTEM)
“The Toyota V8 CRD is very under stressed so it’s probably the TD42 of the CRD engines.”
2.5L NISSAN NAVARA/PATHFINDER (DENSO SYSTEM)
“We have one that’s travelled 200,000km across this country. Serviced regularly with no issues.”
2.5L MITSUBISHI TRITON (DENSO SYSTEM)
“One of the older CRD engines and is trouble free from our end.”
3.2L MITSUBISHI PAJERO (DENSO SYSTEM)
“Another older CRD engine we see little to no issues… Don’t buy the model with diesel particulate filter, though!”
3.0L ISUZU D-MAX (BOSCH SYSTEM)
“Isuzu….truck proven.”
MTQ ENGINE SYSTEMS
Tony Martin
“Most common-rails will respond to upgrades. It is not unreasonable to expect gains of 20% or more by fitting a chip and exhaust package.”
3.0L MAZDA/FORD RANGER (SIEMENS SYSTEM)
“Responds well to a chip. Made the highest HP as tested by 4WD Action with a Rapid module.”
3.0L ISUZU D-MAX (BOSCH SYSTEM)
“Responds well to performance module and exhaust. Hardly ever see these in the workshop.”
2.5L MITSUBISHI TRITON (DENSO SYSTEM)
“Has issues with carbon build up in the intake manifold so I recommend regular use of intake manifold cleaners that are suitable for diesel engines. But otherwise a solid performer.”
3.0L D-4D HILUX (DENSO SYSTEM)
“Injectors aside, they are a tough motor. The best thing about the Toyota is when the vehicle has a fault, in most cases, it will not shut down the vehicle completely – it goes into a reduced power mode but it will still run.”
BAILEYS DIESEL GROUP
Matt Bailey
“Anything with a Bosch fuel system seems not to suffer the same reliability issues as others.”
3.0L 4JJ1 ISUZU D-MAX/ COLORADO (BOSCH SYSTEM)
“We don’t see many of these at all. We only ever see these if the fuel has been contaminated, which is a problem that can affect any vehicle.”
4.5L 1VD-FTV TOYOTA LANDCRUISER (DENSO SYSTEM)
“These engines are a lot less stressed than the D-4D 1KD (HiLux) engine. They run lower fuel rail pressures, the engine RPM are lower and the average injector life is roughly 250,000km, as opposed to 175,000km for the 1KD.”
GETTING YOUR COMMON-RAIL SERVICED
CAN YOU WORK ON A CRD YOURSELF?
Andrew Leimroth, Berrima Diesel
“Generally there is nothing to touch other than normal service items like filters so it’s not a problem. In the early days of CRD release there was a lot of talk about the safety around the fuel injection parts due to dangerously high pressure. Basically this faded away as people realised that any fuel pressure areas touched had pressure but very little volume.”
WHAT ABOUT DIESELS THAT CLAIM 15,000KM INTERVALS? SHOULD I SERVICE MINE EVERY 5,000KM?
“Manufacturers aren’t interested in hearing their engine lasted 300,000km+, but you are. I recommend a flexible mindset to oil changes and service work. Do short runs over 6 months and change the oil every 5,000km. If you do quick mileage with little stress on the vehicle in 6 months, then you can stretch it anything up to 10,000km. Don’t forget – you change oil because it’s saturated with carbon deposits (among other things). The fact that CRD engines may run cleaner is one reason for the extended oil change idea. But like we’re seeing with the HiLux D-4D engines, regular oil changes will almost certainly prolong the life of any engine.”
HOW COME REPAIRS COST SO MUCH?
Scott Wood, Denco Diesel
“Repair costs are relative to older systems with the exception of contamination. Contamination in a common-rail often damages all of the components it comes in contact with, and all of these parts must be replaced to prevent further failures. If injectors fail as the result of contamination there is no point replacing just these units as they are at the end of the line and will be re-contaminated with the particles that are still present within the pump, rail and lines.
If any repairs are required, it’s essential it’s carried out in a purpose built clean room, filtered to 0.5 micron, to ensure that the product will not fail. Testing of these components requires specialist equipment with protective cages over the benches to protect the operator as pressure equal to what is provided on the vehicle, up to 2200 bar, needs to be generated to check the operation of the component against the manufactures specification. Unfortunately this sort of stuff doesn’t come cheap.”
WILL COMMON-RAIL DIESEL ENGINES LAST?
How will common-rail engines fare in 30 years time? And what can you do to make yours last?
WILL THEY SEE 30 YEARS?
Tony Martin, MTQ Engine Systems
“This will depend on the vehicle and how it is maintained. My concern is the electronics lasting and parts availability for people to keep them maintained and on the road.”
Matt Bailey, Baileys Diesel Group
“Yes, with maintenance.”
Andrew Leimroth, Berrima Diesel
“The engine may but will the rest of the stuff running it? With good maintenance it should.”
Scott Wood, Denco Diesel
“With quality fuel the systems are reliable. We’ve seen them last to 500,000km without incident.”
HOW TO EXTEND THE LIFE OF A COMMON-RAIL MOTOR
Scott Wood, Denco Diesel
“Water ingress is the main cause of failure in all common-rail systems. Simple things can be done to prevent these failures like using only genuine filters, and regularly inspecting the fuel system to ensure water is not present.
As most common-rail pumps control pressure by regulating the fuel entering the pumping plungers, we recommend that devices that cause additional restriction, such as extra filters, not be fitted. A water trap with an internal diffuser can be fitted to most vehicles which are designed to catch water with minimal restriction. Some of these are available with sensors to alert the driver that water is present. With quality fuel the systems are reliable. We have seen some vehicles exceed 500,000km without incident.”
DON’T HEAD OFF-ROAD WITHOUT…
Andrew Leimroth, Berrima Diesel
“It’s almost essential these days to carry a diagnostic tool that allows you to reset fault codes if a problem arises while you’re off-road. Often, the computer will put the engine into a ‘fail safe’ mode if a fault occurs regardless of the severity, and it could simply shut the engine down. It’s the engine’s way of protecting itself, the problem is, it can leave you stranded. A diagnostic tool like the EDS allows you to monitor exactly what the engine is doing in real time, and also allows you to read and reset fault codes.”
PROTECTING YOUR INVESTMENT
There’s no doubt about it, small capacity engines are the way of the future, and experts agree, that with the right care and maintenance these engines will last as long as any largercapacity mechanical diesel. They are predicting, however, that parts like your turbo and fuel injectors should be considered ‘serviceable items’, much like your clutch or timing belt, and it should be expected to repair or replace these parts at given intervals for the overall good of your engine.
When it comes to power up modifications, go with a reputable brand and tuner, and err on the side of caution when it comes to extracting more power if you want it to last well in to the future. Routine servicing every 5,000km using quality parts and the use of clean fuel from a reputable supplier will extend the life of any common-rail engine. Water separators offer additional protection and should be considered, too, but it pays to consult a diesel expert when selecting the correct filtration for your vehicle, as some of these fuel systems can be quite temperamental to restrictions in the fuel line.
HOW TO MAKE YOUR CRD GO THE DISTANCE
• Carry out routine engine oil and filter changes every 5,000km.
• Replace the fuel filter every 15,000km.
• Install an OBD-II engine monitor to keep tabs on the health of your engine.
• Have your CRD inspected by a reputable diesel specialist once a year.
• When choosing a power-up mod, only use proven brands and have them installed and tuned by an experienced diesel workshop. Like anything, if you look after it, it’ll look after you.
HOW TO PREVENT YOUR COMMON-RAIL DIESEL FROM FAILING
Stephen Coughlan, Toyota Australia
“Regardless of the brand, common-rail diesel engines utilise precise technology and require diligent maintenance (in-line with the timeframe and mileage stipulated by the manufacturer) as well as good quality diesel fuel to ensure optimal performance and longevity.”
