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The basic reason for replacing v6 and v8’s with smaller displacement boosted 4-cylinder engines is fuel economy. Aside from going to Hybrid powertrains, there is not other way to get such large improvements in fuel efficiency (more than 10%). The basic reason why this works well is that the average amount of power that has to be delivered to the driving wheels is very low compared to the peak power needed for heavy acceleration or hill-climbing. A large sedan only needs about 10-12 HP sent to the drive-shafts to maintain 65mph on a level road. When you throttle a big engine down to 10 HP, it runs very inefficiently. Throttled engines waste energy in the form of pumping work, and large heavily throttled engines also waste a lot of energy in the form of internal friction and heat loss. It is much more efficient to get the same 10-12 HP out of a small-displacement engine that can be boosted for peak performance. It may seem counter-intuitive, but opening the throttle increases efficiency!
Modern 3 and 4-cylinder turbocharged engines are designed and built for excellent durability at full-load. The other reason why many folks have a preference for a 6 or 8 cylinder engine is that they expect less noise and vibration, compared to a 4-cylinder. This is no longer true due to modern methods of isolating engine vibrations through sophisticated motor-mount and driveline technologies. Try any modern BMW, Lexus, or Mercedes 4-cylinder vehicle and you will see what I mean.You can test the PCV valve operation by pulling the pcv hose off the side of the valve that is not attached to the intake manifold and see if there is steady flow of air being drawn in to the valve. PCV valves tend to last a very long time.
Yes it will. Try inspecting the wire and connector to the sensor. Unplug and re-plug. The shop manual will show you how to diagnose whether it is the sensor or the wiring. Avoid driving until this is fixed or you risk damaging the catalytic converter. this could also be the source of misfiring.
The CEL will not turn itself off even if you fix the problem, but you can do it with an inexpensive OBD reader.
Dave
I assume you mean that there is a lot of oil on the exhaust manifold, not in. You certainly want to repair the leaks in the valve cover, but they will not fix you misfire issue. I strongly suggest looking in the factory shop manual before replacing the valve cover gaskets because the manual will tell you if and where you need to use sealant. It is common for corners to need sealant to supplement the gasket. Also, you really should follow the torque specs when you re-tighten the valve cover nuts or bolts. Unless you are an experienced mechanic, tightening by feel can lead to broken fasteners, stripped threads, or future leaks.
You can have weak coils even if they test fine with a multimeter.
If when you moved coils around, the misfire code doesn’t move from one cylinder to another (presumably with the weak coil), your problem is not coils. That is why you swap the coil pack before you buy anything.
I strongly doubt that the misfire has anything to do with the valve cover leak. Oil is non-conductive and is very unlikely to have any effect on the coils. Why throw in the towel? You have just begun the diagnosis process. You should get a copy of the factory shop manual and look up your fault codes. The manual will have a full diagnosis path to follow.
Likely causes are: bad O2 sensor, dirty MAF sensor, clogged fuel injectors.It is not just the life of the plugs to consider. Different types of plugs have differing electrical and ignitablity requirements. Most importantly, the spark plug heat range is a critical property for an engine: too cold a plug will foul out quickly and too hot a plug will cause preignition. The Honda TL plugs might be OK, but I wouldn’t risk it. see this: https://rothautomotivescience.com/forums/topic/spark-plug-technology-platinum-iridium-or-copper-spark-plugs/
Dave
The most reliable approach for both experts and non-experts is as follows:
– Start with the OBD reader. There are almost no bad-running conditions that will not throw a fault code on a modern engine. Even if the Check engine Light is not lit, you can have stored codes. Anything that results in misfires or rough running will set a fault code.
– Get a copy of the Factory Shop Manual and look up the section in it that corresponds to your stored faults, This will be in a separate Diagnostic section or in the section with the engine computer (ECU) or fuel system, or Engine-Electric section.
– The shop manual will have a step-by-step procedure for diagnosing every error code, and usually all it requires is a Volt-Ohm meter.You should use the brand and part number spark plug that is listed in your owner’s or shop manual. It is always a bad idea to try a different type of spark plug than the car maker specifies. (don’t use a copper plug when a dual-fine-wire Iridium plug is called for)
You can also do well by going to the Denso or NGK website and lookin up the proper plug for you engine.
Regarding coils; I know too many folks who have had bad experience (short life) with aftermarket coils.
The issue can be a faulty igniter (coil-on-plug), fuel injector, or spark plug. The first thing I would do is move the igniter on the identified cylinder and see if the code changes to that cylinder. If it does, then you know it is the igniter that has to be replaced. OBD readers are not expensive, you should buy one. Also fix this ASAP because a misfire can destroy your catalytic converter pretty quickly. The spark plug is the least likely cause.
Changing spark plugs should be considered preventive maintenance. Do this to avoid engine issues. In general, old spark plugs will work fine and the engine should run normally. As a spark plug gets near the end of its useful life, first cold-start may get worse, and then idle quality will begin to suffer. Change the plugs on a schedule according to the owner’s manual and you should never have an issue. You don’t expect a big benefit or even a noticeable benefit, you just avoid ever having a poorly running engine condition that just keeps getting worse.
An engine can have problems with cold-start because the starter motor has a huge current draw because the starter motor has a lot of work to do to get an engine spinning fast-enough to start. EV’s do not have this problem, no starter motor, no really big start-up electric loads. Ev’s can have an issue with cold-weather performance and range because the heater/defroster is all-electric and takes its power from the same batteries that propel the vehicle. A lot of this can be avoided if you program the car to pre-heat while it is being charged. Also, the batteries can’t deliver full-power when they are very cold (below 0F), but the batteries get warmer naturally as you drive. When you consider buying an EV read the manufacturers recommendation about severe cold operation.
Correct, a lower capacity battery will not have any negative effects on the engine or charging system. The battery companies all make different CCA capacity batteries in each battery-frame size. The higher the CCA, the more the battery weighs and costs.
Dave
