Engine knocking, only 30k miles
 

I got my 13 Fit used, it had around 24k miles when I bought it a year ago. I had a 13 Fit (manual) I bought new, that was totalled. My wife has a 10 Fit automatic also bought new. I know how a good Fit engine should sound.

I hear a rather pronounced knocking sound when I drive it, at certain RPMs and conditions:

• When the engine is cold, it does NOT make the sound. When it's just warmed up enough, I can run it fast up to redline and it sounds great and normal. VTEC, yo.
• After several minutes, at least 5 or more, the knock sound starts to happen.
• The knock sound happens primarily between 2000 and 3500 rpm, when I am driving slowly and in too high a gear. Such as, I am lugging it a bit or trying to accelerate when I should downshift. OR when driving at the appropriate speed, just at that RPM and give it a little gas, such as going uphill. The knocking occurs. Soon as I lift off the gas a bit, the sound quiets down.
• If I were to drive a short distance, park, do an errand, come back, the sound is worse, as it seems the engine has fully heated up.
• The knocking does not happen when I am driving fast, think like autocross, or over 3500 rpm.
• At highway speeds, the sound is not really noticeable.
• Lastly, I've been using 87 octane. I recently put a tank of 93 and the knock seems a little less. My drive to work is very short so it takes a long time till I need gas again (several weeks sometimes).
• The sound is totally rpm related. It is not wheel related. It is not a heat shield. But I wouldn't rule out (manual) transmission possibly.

Our Honda dealer thinks it's normal or no problem. The reason I think this is an issue is I have had 2 oil analysis done, when I bought it, then just recently, and it came back with very high aluminum and iron content.

The previous owner lived in Pittsburgh and had it parked pointing downhill on a relatively steep hill. Would that have starved the engine of oil and caused some premature wear?

I think that my engine has a bad knocking issue. I've been able to run 87 octane and next tank 93 octane and the knocking is far less when using 93. I'm surprised since I never thought that the L engine needed higher octane.

I would put a fresh set of Denso IK22 spark plugs in it and run, at minimum, 89 octane.

Everyone wants to run cheap fuel, but at the end of the day these are 10.5:1 compression motors. The ECU can retard the timing enough to run 87, but is that a good idea?

Also, what motor oil are you running? Spec is synthetic and I would consider the Honda OEM oil to be the bare minimum.

Aluminum and iron in the oil is not a good thing. I'd try the above suggestions along with a pure synthetic oil and try another test.

The car is used so I don't know what the previous owner did. She said she took it to a private mechanic a few times. I always go to the Honda dealer, and let them do the oil change. So it's whatever Honda oil is, which is I believe rebranded Mobil 1, at least that's what I either deduced or asked the dealer a long time ago.

I'd get the oil pressure checked.

I hate that answer from dealership service departments.
The OP owns a Fit and has owned multiple Honda Fits, PLUS has gone to the extra diagnostic step of having their oil analysed.

How about the service department default to the idea that there IS a potential problem and be supportive of seeking an answer instead of blowing it off with a "it's normal" answer.

A "knocking" engine, that isn't a diesel, isn't "normal" IMO.
The problem is there are a lot of things that can cause this symptom. But I suspect you have a problem here.

The first thing I would do is try to find a reputable, skilled service department that is willing to help you pursue an answer, instead of just giving you a "No Help" definition.

At least in the US, spec is 87 octane or above (so no timing is being pulled to run it) and conventional 0W20 motor oil (synthetic is specified where required):
http://techinfo.honda.com/rjanisis/p...3/K61313OM.PDF

That is NOT true. 87 or above just means it can run on 87. It does not mean that it's not pulling timing.

I've been running 93 octane lately and it has helped reduce the knocking. But I still get some. I have not replaced spark plugs yet.

I think that I probably do have some bearing (or something) wear. I'll keep getting oil analysis on it.

I'm still somewhat worried about it, but I am probably not going to do anything major until the engine gets very bad. Cost to replace a motor completely is probably about the same, or less, than major repairs.

My opinion about the dealership is that they probably: Took a test drive without me and never actually heard the knock. And/Or they also didn't want to warranty repair/replace the motor.

Have you checked the plugs for tightness?

A large percent of these motors experience a loosening plug issue. You may be hearing a plug leaking around the threads.

When ours starts making noise, I tighten the #3 cylinder plug and all is good until it loosens again.

I've did that very soon after I got the car. Had to do it on my other 13, but wife's car has been AOK to date. I guess it's possible but I smelled gas before, didnt have knocking.

There are many owners who get alarmed by the knocking and ticking sounds the L15A makes; there are endless threads and there is unlimited obsessing and many theories, from noisy injectors to serious engine damage. When I removed my plugs the first time there were carbon trails up the threads that indicated they all had been leaking. After new Denso Iridiums torqued properly and a valve adjustment, I picked up 2 mpg highway which has remained. I am meticulous with adjusting valves etc. and after 195,000 miles I continue to assert that the L15A sounds like an old sewing machine and it changes with temperature. There is absolutely nothing you can do about it and no reason whatsoever to worry. How it runs is the benchmark, and mine continues to perform excellently despite how it sounds, which is often deplorable, but I have decided my ego can handle it. Just tune it properly; I prefer Denso Iridium TT's myself, and just drive it. If it explodes, then you will know that there is something actually wrong, but I honestly and seriously doubt it.

Dear SuperMacGuy.The analysis of the oil leads me to suspect problems of wear. I think your engine may be under excessive wear on crankshaft bearings and / or connecting rod bearings or maybe some piston pin with slack hitting. It would be best to disassemble the engine and repair but if you dont want to do it, use it without forcing too much and always paying attention if the knocks increase. Who knows if the previous owner maltreated the engine using it at high RPM or then overloaded the engine until it damaged or used the engine with low oil volume. Greetings.