Every car I’ve owned no matter what size, cylinders, or horsepower, always seem to lose their original “kick” with age. My 97’ Accord 4-cyl manual with 140K mi still is a wonderful car but it has nowhere near the acceleration it did in it’s early years.
Is this strictly due to engine wear and tear? What type of tune-up fixes could restore some of this power or is it just pointless to try to get it back?
It’s had it’s regular maintenance (fuel filter, air filter, spark plugs, oil changes, fuel injector cleaning, etc. etc.)
Can anyone point to a “get this cleaned” or “get this replaced” to make a noticeable difference??
The biggest wear items that reduce power are piston rings/cylinder walls and valves/valve seats. Your local mechanic can easily do a compression or leakdown test to see how well these items seal the cylinder under pressure. Heck, I have a compression tester gathering dust in my toolbox if you want it. It screws in place of a spark plug and has a pressure gauge at the end of a short hose. You crank the engine over and the pressure reading tells you one measure of your engine’s health comared to a new one of the same type.
Unfortunately none of those are tuneup items as they involve tearing the engine down and doing specialized machine work.
Oxygen sensor(s) are often ignored during the tuneup, especially by do it yer own selfers. Depending on the car you’ll have 1-4 of the little buggers. They are screwed into the exhaust manifold perpendicular to the pipe, always before the catalytic converter, sometimes behind it as well. They are pretty big, think large spark plug, and they have a wire leading from the sensor to a brain. Replace them when you do the spark plugs. They run $25-$60 apiece.
They basicaly sniff the exhaust and send the results to a computer, which in turn regulates the fuel/air mixture. When they go bad, the computer often decides that the best way to remedy the odd reading is to add more fuel, less air. Performance suffers, fuel economy suffers (up to 30% sometimes!), and the bad mix can foul your plugs and clog your catalytic converter further reducing performance. There is some speculation that a bad oxygen sensor was to blame for the Northridge, CA earthquake a few years ago so you really need to replace them periodically. I replace them whenever I do a tune up for someone, and they almost always mention the power increase to me a few days later. Even folks who you might not expect to notice that kind of thing.
So the Oxygen Sensor, and yeah, fuel injector cleaner a couple times a month. AND there are oil additives akin to Slick 50 that claim to compensate for the worn cylinder/piston rings. I dunno if they work or not.
An often overlooked maintenance item is engine valve adjustment. The official maintenance interval for that is every 15,000 miles; in the real world every 30,000 miles is usually satisfactory. Unfortunately, also in the real world many cars for which it’s applicable (including all Hondas that I’m aware of) never get it done. If your car is one of those, it might help.
While it’s true that oxygen sensors are seldom done as maintenance, every 30,000 miles (spark plug replacement interval for many cars) is really too soon to replace them. Every 60,000 is conservative, and every 100,000 is reasonable for the great majority of cars.
Allow me to point out the correct way to check your compression.
1 insert checker and crank the engine to obtain a reading----crank for at least 5 seconds
2 Record reading and cylinder number
3 Remove checker and squirt about an ounce of oil into the cylinder
4 re-install checker and crank the engine for another few seconds and record reading
The second reading will probably be higher than the first
Do this on all cylinders, recording as you go.
A comparison of your final readings will tell you the story----------any readings that are lower than the others will indicate either ring wear or poor valve seals.
Check with your dealer to find out what normal compression is.
If ALL are even in pressure but much lower than normal for that engine then you have normal compression loss due to wear.
If only one or two are lower than the average of the others you have individual cylinder probems.
The second reading is the most important because the oil you’ve injected momentarily,and partially,seals off any leaks.
An even better and more reliable method than the above is called a leakdown test. Starting with cylinder #1, the piston is brought up to TDC then pressurized to a specific amount of air pressure. Then over a timed period, usually 30 seconds, you measure how much pressure is lost. Each cylinder is done one at a time. From this you will get a percentage for each cylinder and the engine as a whole. A brand new engine will show virtually no loss while a 100,000 engine will be lucky to reach 25%. Plus by listening into the crankcase, intake manifold and exhaust, you can tell if the leakage is through a valve or the piston rings.
Are you basing this on your impression and recollection alone, or on some measurements - like quarter-mile times or dyno numbers?
Cars have become more and more powerful over time, and over the last 5-10 model years especially. A '97 Accord may have been zippy when it was new, but an '04 Accord V6 probably has at least twice the horsepower. By comparison with a newer car, then, the '97 may seem much slower, even if it hasn’t actually changed much.