Sounds a little different. Keep us posted if you pursue this further. I still do not think this is anything to worry about. I will record mind and post clip. I said this before but have been very busy.

 

The engine does sound stronger. Your mpg should be better too. So whats next?

 

Tough call from here onwards, pretty confident that we have eliminated any other possible external causes ( accessories, tranny, clutch, mounts etc).

I spent a good amount of time with a stethoscope around the engine bay to track down the knock but nothing. I could locate most sounds quite easily but the source of the knock cannot be found. The clearest way I could hear it was to idle the car while the front 2 wheels were on jackstands and myself underneath with the scope. It's definitely coming from the within the block. I have sent an email to my Honda dealer saying the noise is still there.

What happens from here is anyone's guess.... But most probable options are for them to do exploratory diagnosis (taking the engine apart) or to have a new engine installed. Either one of them aren't exactly great outcomes. All I can say is that if the problem can't be fixed before the end of warranty, then I don't see myself keeping this car for the long run.

 

Good luck. Easiest way to determine if it is a rod knock is pull one plug/coil at a time with engine running if noise goes away you found the cylinder the problem is in. Come to think about this noise my 91 Hatch had the same noise when I was under the car listening to it. Car had 234000 miles and ran great idle perfectly, etc. This engine I also put in new rod bearings when I replaced rings because engine burnt oil when I purchased it with 117000 miles. Car sat for a few years and the rings gummed up. Again, I considered this normal never heard it unless I was under car with my ear close to pan. Not a reliability issue in my eyes.

 

You can use a UG or scanner that shows timing you can check for engine knock. The only problem is it wont tell what cylinder but after driving let the engine idle. Note the timing at idle. Tap the engine around number 1 cylinder and see what the timing does it should retard the timing and after a while go back to normal. If it works out that way then the knock you hear is normal.

Keep using the 95 ron fuel or higher so the engine is not knock limited. Is there any other symptoms?

 

fer cryin out loud! enough with higher octane. the sound is at idle. It's not random pre-ignition.

I recommend playing the radio louder and ignoring it. It's a noisy engine.

 

Steve the engine is Knock limited with regular gas and premium is only higher octane but not high octane. 116 unleaded racing fuel is high octane. Honda is tuned form the factory to use 91 octane or 95 ron fuel. It can use higher or lower octane than that but you have a loss of benefits. MBT timing is where the engine works the best and is set at 95 ron fuels.

 

his noise has nothing to do with pre-ignition knocking. it's a honda econ box designed to run on regular gas. get over it.

 

If that knock is engine related it will show up on the knock sensor. Its just peace of mind that I am getting him too. Any high volume car sold has to run on regular because its the law and has nothing to do with its requirements. Honda even says 87 or 91 ron or higher and there is 2 fuel requirements mon and ron for different conditions. 91 r/m fuel is in the middle.

 

Of course it has to do with with the Fit's requirements. otherwise Honda would recommend or require higher octane. You don't think maybe Honda was involved in its design?

Honda's anti-knock requirement in the Fit in the US ( (RON+MON)/2 anti knock index) is:
There's nothing wrong with running a higher octane fuel than required. But no study has shown any performance gains for any car where higher octane is neither recommended or required, either at the pump or on a dyno.

 

Guys thanks for the help, so to clarify I can try the below options:

1. Unplugging coils one at a time whilst idling to determine if it is rod knock and which cylinder it's coming from. What's the easiest way to get to them? Not much space so I'm assuming the wipers and cowl have to come off to reach them. Any other alternatives? If not I can give this a shot on the weekend.

2. Ultra gauge or scan gauges, I ended up selling mine about 6 months ago so I don't have one readily I can pick from.

Also as a note about fuel, the 91+E10 here in Australia can be quite mixed in quality at times which is why a lot of people recommend using 95, not for performance gain but a better grade of fuel.

Other GE's I've seen were running 91 without the knock that I have so I don't think it's to do with fuel.

Also the knock I hear only happens at idle when the car is hot. Only other symptoms is a slight vibration at idle but that's probably to do with the mounts then anything else.

 

You got it for the most part. About the coils I would wait and look for air leaks and clean the throttle body and disconnect the battery for a reset first. I doubt anything will change but it will help in the long run. You got it on the fuel and its more to cycle to cycle variations that occur and the closer you run to MBT the better the engine will run.

You dont want to disconnect the coils when its running...

 

Any particular reason why the coils shouldn't be disconnected? sorry if its a basic question, but I've seen people do this in the past as form of diagnoses without any negatives. Also have seen people isolate injectors one at a time using the same idea.

 

I don't think its a coil problem. Here is a guide with some general info. Part 1 -How to Test the Ignition Coils (2001-2005 1.7L Honda)

If its a injector other symptoms would appear too. That is why I said use MMO in my first post.

 

massively multiplayer online?

That may be more effective than some mysteriously marketed oil... (mineral oil, turpentine, and lard.).

 

Link doesn't work?

 

sorry, never posted a youtube video before working on it.

 

Last time mine got loud it was a plug working it's way out. Check the spark plugs for fun.

 

sure, worth a shot. note that the knock I hear is only once warm and idling though, so in theory If it was a loose spark plug I should be able to hear when cold as well.

anyhow, the car is going back to my Honda Dealer again this week for a final diagnosis, if they don't find the source of the knock then Honda will get involved.

Either way I'd like to get to the bottom of this as I've found a handful of fit owners that have had a similar case to this without any resolution.

 

Heres the video, thanks for the pointer on how to do it was doing the YouTube in brackets with YouTube video number in between them. Hope this helps as a reference. It does not seem to have the same noise. Sound is not very good but at the end of video you can hear engine idling doesn't have that noise though.