treks

It is common for this of problem to get better when the gearbox heats up a bit, because the heat helps to release moving parts in the valve body. Please let us know what you find when you have the gearbox checked out.

Self-driving cars may be the way of the future, but as @Technician says, that future is a very long way off. There are just to many things that can still go wrong to make driverless cars a viable transport option in the foreseeable future.

I agree that the mountings might be the problem but there are other possibilities. Normally when mountings are worn or broken, you would get a "thumping", or "thudding" sound under hard acceleration. Does this happen at all? Also, has the shifting changed at all? For instance, is the shifting now hard, harsh, or different in any way than it was before? Does the vibration go away when you shift into Drive? If the mountings were shot, you would get this vibration all the time when you hold the car with the brakes while it is in gear, and not only in Neutral or Reverse. It is entirely possible that the gearbox is not fully disengaging when it is in neutral, or that when it is reverse, some of the pressure in the valve body is diverted into another circuit, which places the gearbox partially into reverse, and one forward gear at the same time. If this were my car, I would get the gearbox checked out, or at least have the fluid checked/replaced before I would change the mountings. Anyway, please let us know what you find.

Just goes to show that regular servicing really does work.

@cyborg, I completely agree with you. One would have thought that it would be relatively simple to design the system so that the fault is pinpointed exactly, but then again if the car makers did that, they would not make any money with repairs. On a serious note though- the more complicated the electronics on cars get, the more difficult it becomes to design diagnostic systems because the number of feedback loops have to be extended to every controller everytime a feature such as traction control is added. This is almost the same as adding a computer to an office network. When one computer in the network fails, the whole network can crash, and it is not always easy to pinpoint which system in which computer crashed because the entire network is down.

Hi Akeem, Code P0601 is bad news, no matter what you drive and the solution is never as simple as checking battery terminals. This code refers to a breakdown in communication between the various computers and controllers in a car. This communication system is known as the CAN bus (Controller Area Network) and works almost like a miniature internet in the sense that all the computers that control the various functions of a car are in constant communication with each other and the ECU. Here is a simplified example- Imagine that the ECU receives a signal from the vehicle speed sensor. Provided that the signal is valid and that the CAN system is in good working order, the ECU will make the signal available to the- · cruise control system (if fitted) for speed control purposes, · ABS brakes system, which will compare the signal and the actual vehicle speed to information collected from the wheel speed sensors to arm the brake, stability and traction control systems, · fuel management system via the throttle position sensor (and others) for the purposes of calculating an appropriate fuel delivery strategy, · transmission control system to regulate efficient shifting, · and the proximity warning system, among others. Now here is the biggest issue- This code does not even identify an area in the CAN system in which the fault may be present. All it does is say that there is a problem somewhere in the system, which means that to find the problem, a mechanic must test each of the several hundred circuits that make up the system individually for ground, reference voltage, continuity, and resistance. Doing this can take a week or more, so it is sometimes cheaper to replace the entire harness. However, the fault may not be in the wiring, but in any one or more computers/controllers, including the ECU, but the thing is that many controllers cannot be tested reliably. So if the mechanic has a code reader that works on the SAE J1939, GMLAN, SAE J1587, and LIN diagnostic protocols, he might be able to use the freeze frame data to see which are(s) of the CAN system were affected first. In this way, it may, or may not be possible to trace the defective controller. Another problem is that some controllers on some cars lose their memory when a breakdown in communication occurs, even if those controllers were not the cause of the problem. This means that while the mechanic is testing each of the hundreds of circuits, he might come across what might seem like defective controllers, while in reality, these controllers may have lost their memories because something else had failed. So, if the mechanic replaces the wiring harness but the code persists, the fault may be in any of the controllers. Control modules can fail for any number of reasons, and as @Technician correctly says, these causes could include corroded battery terminals, low battery voltages, or charging system issues. However, fixing these issues won't fix the fault in the CAN system. Code P0601 is perhaps the most difficult code of all to diagnose and repair, and your mechanic is not altogether wrong when he says that he may have to replace all the wiring and computers to fix the problem. It is not that he is greedy or incompetent- it is just extremely difficult to find the problem, and there is a distinct possibilty that the root cause of the problem may never be found. I am sorry I don't have better news for you. You can try to replace just the ECU, but there is no guarantee that this will solve the problem. You can also try to reprogram the ECU, but again, there are no guarantees. The only logical thing to do is to have the entire wiring harness removed and inspected before you start replacing control modules.

Looking at the pics in this thread, I wonder what happened to the guys who said that we should grow up, or find a more rational approach in our efforts to save the planet?

Do you realy want to start another uproar?

@amitaj, there is a small problem with Tesla and other electric cars that can make 426 kms per charge. For instance, where will the electricity come from to recharge a billion Teslas? You may also want to rethink your position on cow dung- you may not have seen a cow in the past 5 years, but the fact is that there are now more cows in South America than people. Lastly, you may want to check out another post by @Technician about what happens when lithium is mined to make electric car batteries with.

Rational approach? When last did you see smog hanging over a city- smog caused by cars burning fossil fuels? Scam? Of course, cars are not the only cause of global warming, and there is some evidence to suggest that the large number of cows and sheep on Earth releasing methane into the atmosphere cause more damage than cars do. Doesn't mean that burning fossil fuels in cars don't contribute though. As for ethanol as fuel- there is simply not enough plant metrial on the planet to make enough ethanol to replace fossil fuel. Besides, the amount of energy required by burning fossil to make the enthanol being produced cause more damage to the atmosphere than the amount of emisions saved by using ethanol as fuel. Ergo, nothing is gained by using ethanol. I also agree that setting off nuclear bombs is a bad thing. You are right, the first internal combustion engines were designed to run on vegetable oil- until cheaper fossil fuels came along. It might be worth noting that even the best-made bio-diesel releases more nitrous oxide into the atmosphere than regular diesel does. Nitrous oxide is the substance in exhaust emissions that cause smog. As matters now stand, there simply is no viable large-scale replacement for fossil fuels, so the only way to reduce emissions is to burn less fuel, and using smaller cars is a sure-fire way of doing that. No matter anybody's point of view- there is no getting past the fact that burning less fuel causes less emissions, unless of course the Martians among us have found a beter way?

Hi Ging, Thanks for your input, but what planet are you from?

@Technician You are right about the production costs of hydrogen, but a bigger problem is the storage and distribution of hydrogen. The molecules of the gas are so small that they escape through the walls of normal storage tanks and pipes, almost like water through a sieve. In the few race cars that use hydrogen as fuel the tanks and pipes are so thick and heavy that these cars carry a significant weight penalty. But I agree- hydrogen could be the perfect fuel if the problems with producing, storing, and distributing it can be solved. Hydrogen fuel cells might work, but they still need a lot of development to make them a viable alternative to fossil fuels.

@ethan- Exactly!

@Gaurav makes an excellent point in that fast accelaration can be a safety feature, but you don't need a V8 to get good acceleration. There are many smaller cars with smaller engines that eat Mustangs alive, and they use less fuel doing so than the Mustang does by just trying to keep up. I submit that smaller cars with smaller engines can be just as much fun to drive as any Mustang or Corvette, but for all that, we have to admit that the planet is in real trouble. One Mustang may not contribute to the problem in any meaningful way, but the problem is that there are millions of Mustangs and Corvettes that do play a major part in global warming, as in fact, all internal combustion engines do. Developments in fuel efficiency and emission control can only go so far. In fact, some emission control devices like DPF filters on diesels wipe out most of the advantages of other emission control measures. The real solution to the problem of emissions requires the development of entirely new automotive technologies. One solution might be steam power, but a suitable heat source is a little problematic at this time. Somebody once sugested that small nuclear reactors might work, but the idea of hundreds of millions of nuclear reactors on the roads seems more of a nightmare than all of the billions of internal combustion engines in operation today can ever be. One day in the not-too-distant future the oil WILL run out, and with the poor performance and range of most electric cars, it seems that electricity is not a viable alternative. Any ideas on alternative power plants for cars of the future?

I agree with @Technician. However,I don't think we as drivers and car owners are the real problem. The real problem is the gangs of marketing experts the car makers use to appeal to our vanity. In really competitive societies it does not take much to persuade a junior manager that he can feel as powerful and important as the CEO- all he has to do is buy a big truck with all the bells and whistles to give him that false sense of power, and feeling of being superior to his juniors who cannot afford a big flashy truck. I think one sure-fire way to reduce the number of unnecessarily large and powerful vehicles is for governments the world over to set limits to the amount of money car makers can spend on advertising vehicles that serve no useful purpose. For instance, car makers cannot advertise big trucks like Dodge Rams and Ford F150's for recreational purposes, and they can only be sold to legitimate business and contractors who tend to use trucks for the purposes they were designed for- to haul medium sized loads. The same should go for powerful V8 cars. If you don't participate in motor sport, you can't buy one. What do you guys thing of this idea? Crazy, or good for the planet?

Spec sheets mean nothing in themselves, since they don't list the additive packages added to the base oil. The lubrication requirements of diesel engines are so different from those of petrol engines that no multi-purpose oil can ever be as good for either type of engine as an oil that is designed for a specific application can be. I will post more on this early next week, so watch this space.

Which is why fully synthetic oil is the oil to go with. Synthetic oil provides almost twice the lubrication of even the best mineral oil, so using fully synthetic oil from the get-go is a sure- fire way to reduce engine wear. Once an engine (Honda or otherwise) is worn no oil can save it, so the reasonable thing to do is to use an oil that reduces engine wear to the minimum- low compression ratio or not.

HI Aalim, As @cyborg points out, bigger wheels will give you a bit of extra ground clearance, but that is it. Fitting bigger wheels does not make a car stronger, or give it more pulling power. In fact, there is no relationship between wheel diameter and torque, since wheels are driven from their centres, meaning that the definition of torque, "Force Multiplied By Distance", does not apply. However, the diameter of the driving wheels is only one factor in the equation that determines how fast a car moves at any given engine speed in a given gear. Therefore, if a car moves at speed X at 2000 RPM in first gear, the road speed and RPM will both change if the driving wheels are bigger than standard. This is because a bigger wheel covers a greater distance in one rotation than the standard wheels do. Since the bigger wheels cover more ground than the standard wheels, the engine does not have to run at 2000 RPM in first gear to propel the car at speed "X". In practice, this means that if a cars' most economical speed was say, 120km/h at 3000 RPM in fifth gear with standard wheels, bigger wheels (depending on the size difference) can make the engine run at say, 2700 RPM to maintain 120 km/h. In some cases this is good, since it uses less fuel, but if the wheels are much larger, and especially on smaller cars, it could mean that the engine is running below its maximum torque in any given gear, which is bad, because the final gearing may have changed to the point where bigger throttle openings than normal may be required to overcome the effects of the changed gearing. Changing to slightly bigger wheels is usually not much of a problem, but changing too much larger wheels can have all sorts problems, including making a car use more fuel than before, and causing shifting issues on automatics, since the engine speed now no longer matches the road speed in any given gear- which is one of the conditions that has to be met before a transmission will shift. Finally, the only reason big trucks use big wheels is because big wheels are designed to carry the weight of the truck and its load. The final pulling power of a vehicle is determined by the engine and gearing in the transmission and differential(s), and has nothing to do with the size of the wheels.

The only thing I can agree with you on in this post is that diferent brands of oil should not be mixed. What is your reason for saying that synthetic oil will "not survive in that condition"? Fully synthetic oil is standard factory fill on many cars in some of the coldest countries on the planet. Moreover, saying that the OP should change to mineral oil because synthetic oil "vaporises" in some conditions is bad advice, since oil cannot "vaporise". It can only be burned if the engine is worn.

I agree with @Imaan that even though oil may be branded as synthetic, it does not mean that is synthetic. Unless you are an expert in oil analysis, you never know what you get when you buy some brands of oil. I must also point out that due to the difference in size between mineral oil molecules, and synthetic oil molecules, oil consumption can rise sharply when you change to mineral oil after using synthetic oil. The reason for this is the fact that mineral oil molecules are not the same size, and the smallest molecules (that are often smaller than the molecules in synthetic oil) can, and do slip through and past the rings. By contrast, synthetic oil molecules are all exactly the same size, and engines that are designed for synthetic oil have such small clearances that the oil molecules cannot slip past the rings. As someone else pointed out in this trhead, the best thing to do is to buy international oil brands, and specifically those brands that carry the European and Japanese oil standard badges. These oils are designed with specific cars in mind, meaning that they are formulated for specific makes of cars. Stay away from generic brands, and never use mineral oil when synthetic oils is recommended by a car manufacturer.

Brake torque is an important aspect of the physics of brake systems, and it must always be borne in mind when brakes are upgraded, or if you want to change to bigger wheels. The best way to explain brake torque is to compare a car wheel to a torque wrench. With a torque wrench, the amount of force required to torque a bolt is dependent on the lenght of the tool, since torque is defined as "Force Multiplied by Distance". If for instance you need to apply a force of say, 10 kg to a torque wrench that is say, 600 mm long to torque a bolt, but you lengthen the tool to 1200 mm, you will only need to apply a force of 5 kg to torque that same bolt to the same value. Similarly, if you make the tool only 300 mm long, you will need to apply a force of 20 kg to torque the bolt. Much the same thing happens with a car wheel. The distance from the center of the wheel to the point of contact with the road can be compared to the length of the torque wrench. The distance from the certer of the brake disc to its outside diameter can be compared to the force required to torque a bolt, but in this case, the torque works in reverse to stop the wheel. Nonetheles, the principle of "Force Multiplied by Distance" remains the same. "Force" as it applies to a rotating wheel is generated by the motion of the car (for our purposes, we will ignore the kinetic energy of the wheel) , and "Distance" is the relationship between the diameters of the wheel and the disc. The difference between the diameters of the wheel and the brake disc can be compared to the length of atorque wrench. Thus, the bigger the difference between the diameters of the wheel and brake disc, the more brake force is required to stop the wheel, since the effect is the same as making the torque wrench shorter, while "Force" remains the same. Fitting smaller wheels reduce the difference in diameter between the wheel and the brake disc, which is the same as making the torque wrench longer, which in turn reduces the brake force required to stop the wheel. Brake upgrades often involve fitting slighty larger discs, which has the same effect as changing (reducing) the wheel size. Therfore, upgrading brakes by fitting bigger discs only works if the wheel size remains the same, because if you fit bigger wheels at the same time, you lose the advantage of the bigger discs that reduce the difference in the relative diameters of the wheel and the disc.

@Technician is right, but he left out the losses caused by the water and oil pumps. Generally, the smaller the engine, the bigger the losses caused by the oil and water pumps. In the old days when cars still had fixed radiator fans, the fan alone accounted for about 20% of the total parasitic power loss.

I must agree with Gaurav that the Lexus 3UZ-FE engine is great, but the problem with Lexus engines is that they need to be mated to their original transmissions to work properly. It is possible to use other transmisions and ECU's with Lexus engines, but I have never seen this work as well as the original engine/transmission combination. With Lexus, the engine, transmission, and ECU work together in the sense that the transmission controls the engine, but this is such a great combination that it does not make sense to want to use another transmission anyway.

For me it must be the LS series made by GM. Bullet proof, bomb proof, and best of all, proof against engine tuners of all inclinations and proclivities.

Hi Hudad, I find it strange that your mechanic is assuming that the misfire is caused by low compression on one cylinder. The fact is that there are so few diesel engines in the UAE that many mechanics can go for several years without ever seeing even the most basic problems on diesel engines. This is off course not their fault, but let us look at the problem in a logical way; Diesels use compression to heat up the air/fuel mixture to the point where it ignites spontaneously. This means that the compression in each cylinder is of critical importance, but a defective injector that injects too much, or too little fuel can also cause a misfire because like a petrol engine, a diesel requires an exact amount of fuel before the air/fuel mixture will ignite. In practice, too much diesel floods the cylinder, and too little diesel starves the cylinder. Much the same thing happens on petrol engines where fuel pressure or injector problems can either starve or flood the engine. The amount of diesel injected into a diesel engine also plays a big part in the final compression, but since diesel engines are much more sensitive to compression than petrol engines are, a misfire, and especially a misfire at idle can have many causes apart from low compression due to leaking valves, rings or a cylinder head gasket. There is no way of telling without a compression test, assuming of course that the misfire is not caused by fuel delivery issues. However, a simple compression test on either a diesel or petrol engine is not always the best way to identify a problem. A much better way to identify small compression losses on both diesel and petrol engines is to do a cylinder leak down test, where the cylinder is placed under pressure while all the valves are closed. Off course, no cylinder is 100% leak proof, but the rate at which the pressure drops is an indicator of how big the overall compression loss is. Pressure can escape through leaking valves, past rings, or through leaks in the head gasket. In the case of a head gasket, the coolant will bubble, or spill out of the radiator, while if it escapes through valves, you can use a stethoscope to identify which valve is leaking by listening for a hissing sound from either the exhaust or the inlet manifold. If the leak is past the rings, there will be hissing sound from the oil filler cap or the dipstick, or both, depending on how fast the pressure is escaping. On blown cylinder head gaskets, the pressure drop is usually quite dramatic, especially if the leak path is between two adjacent cylinders, on one of which there will always be valves that are not fully closed. This test works on both petrol and diesel engines, but you need some experience in doing this test to be able to interpret the results correctly. With compression tests where gauges are screwed into spark plug, or injector holes in the case of diesels, the result can be wildly inaccurate for a number of reasons, chief among which is the fact that small leaks are often not detected because the piston is compressing the air in the cylinder too fast, not allowing small amounts of air to escape fast enough to be detected. This is true for both petrol and diesel engines, so even if the compression gauge says that the compression is fine on all cylinders, there might still be minor compression losses that the gauge does not detect, which could cause misfires on diesels at idling speed. However, on petrol engines, the engine management system often detects misfires that many of us don’t even know are present because they often present no symptoms other than a CHECK ENGINE light and a stored trouble code. A cylinder leak down test will often identify the problem sooner than some inexperienced mechanic can by changing lots of parts in the hope of hitting on the solution by accident.