I have a 2010 Fit Sport with the 1.5la motor. My motor has developed a loud knock. Now I know what a rod knock sounds like and I know they are usually constant even at idle. But mine begins around 2500 rpms. What could be the cause of this?

 

How many miles?

These cars are extremely prone to leaking spark plugs that will eventually be ejected from the head if not caught early. I highly suggest checking the plugs. #3 cylinder seems to be the most common to be affected first.

 

84k. Miles. I'l check the plugs for sure. Any other issues?

 

Hmmm...that's pretty low miles.

Does the sound increase with rpm? Any difference when under load vs just free revving?

I would check the motor mounts and look for an exhaust leak. With the single exhaust port style of the GE Fit's, an exhaust leak has a different sound than normal to me. A friends GE has a rusty exhaust and was leaking at the manifold to downpipe connection.

 

@ GAFIT: Loose spark plugs causing a knock? I'm not disagreeing with you, but you'll have to explain that one to me.

@ HondaTexan 33: A tick is not a knock. Could you elaborate on the symptoms that you are experiencing?

Regarding ticking noises:

1) Our engines have loud injectors. It's something I have never fully adjusted to.

2) Our engines don't tolerate even a slight drop in oil level. If your engine oil is not exactly at the upper limit, you are liable to hear more ticking noise. At least, this has been my experience.

 

It would not cause an engine knock. I'm assuming that the OP is speaking of a sound and not an actual knock.

A loose plug makes the sound of an exhaust leak, but deeper since it's sound is right out of the combustion chamber.

It could be mistaken for a knock sound to some.

 

the sound does grow more rapid with higher rpms. The only difference I've noticed is at which rpm it starts at. Free revving it'l start at 2500 rpms and under load it'l start at 3-3500 rpms.

 

That's unusual!

I'd start with a spark plug, motor mount, and exhaust system check.

I hear of VERY few short block problems, so I'm betting this will trace to something not serious, but you never know.

 

right ok man thanks. I'm hoping it' not serious.

 

Well I don' know exactly what happen under the hood but. While driving at cruising speed, not hot rodding it, the engine shut off. When I came to a stop I attempted to crank the engine. It turned as if trying to start but it never fired. When I checked the oil it appeared then. There was a smell of gas on the rag I wiped my dip stick with. What's happened?

 

I can think of two possibilities...

Stuck injector - hydrolocked the motor
Ejected spark plug

The oil (5w20) starts life pretty thin and used oil always smells like fuel, but if it's really thin and really smells like unburnt gasoline, you may have a stuck injector.

If the car is at your house, reach around the backside of the motor and see if any of the coils are dangling from their wire. When a plug ejects, it blows the coil apart on its way out.

Please let us know what you find. Curious!

 

will do man. I appreciate the advice. I'l keep you posted on the findings.

 

the spark plugs are all in place and tight. There's no play in the coils.

 

84K. Time for a valve adjustment.

 

now the motor turns but won' start. Also there' now gas in the oil.

 

My guess is a leaking injector.

Did you check the plugs for raw fuel?

 

haven't checked the plugs.

 

This might sound crazy but could a valve or two be so out of adjustment that they aren't opening sufficiently, allow pressure to build, forcing gasoline past the rings. As rpms increase the problem cold worsen and you hear the knock. Pure speculation on my part.

Are valves noisy?

 

the valves weren' very noisy. Thete has been a new discovery though. I had an accident back in December and the body shop put my bumper back onto the car, but had trapped muffler behind it. When I loaded the car onto a trailer we noticed that the exhaust had a couple of binds in it. That does support the theory a little bit.