High Knock & STFT1

[Justin]

Hi Guys,

Been struggling with this for a few months with my 2022 Civic SI. I am not sure if these are false readings but they really scare me.... Defnitely considering trading in my car but I'd be at a huge loss. Acura was offering 21k for my civic @ 33k miles and I'm about to pull the trigger.

Symptoms:

1. High Knock count - 10 minute drive will quickly get 10 knocks then stabilize with 1 knock every 2-5 minutes
2. STFT1 is in the positive range. Highest i've seen it go was to +17% but stays between +1 through +10%
3. LTFT2 is stuck at -12%
4. Cylinder 3 has all of the knocks

The good:

1. No CEL
2. ~35mpg
3. No Limp
4. Making plenty of boost on demand (KTUNER TSP Tune)

Troubleshooting:

1. Double checked and tightened Front Engine Mount
2. Replaced stock intake with an Injen Cold Air Intake - Double checked installation for leaks
3. Swapped ignition coils to other cylinders
4. Swapped spark plugs to other cylinders

Sponsored

 

[TypeRD]

I read about a similar issue over in the 10th gen site. The owner went thru the normal process of checking the ignition as you did. After weeks of trying different things (including new plugs and coils), the problem ended up being a weak battery. Others chimed in saying the stock battery is not great. It might be something to look into if your battery is stock, even if it tests OK. It kind of makes sense, per your description of driving for 10 mins and getting several knocks. That might be about how long it’s taking the alternator to recharge it. After that, the alternator still continues to struggle a bit which may be why the knocks continue to happen (though less often). Just a theory. Hope this helps.

 

[Two Step Performance]

Please do not let this "knock count" worry you, it is nothing. "Knock count" ironically has nothing to do with knock. It measures misfire and the sensor is VERY sensitive. If you have a notable amount of misfire (count incrementing by the hundreds) you will see a flashing check engine light and then eventually a full illuminated check engine light. You are not close to either.

Your fuel trims sound decent but may be improved with a higher quality intake. (Unfortunately Injen products are not great in this regard.)

There is definitely nothing wrong with your car so please do not rush to give it away because of that.

 

[TypeRD]

Doing some research, engines actually misfire pretty frequently, we just don’t know about it. This makes sense because nothing works 100% perfect repeatedly. Not even the finest watches on earth can keep time perfectly, but this does not prevent them from operating as intended. There’s always a little (non-volatile) variability. To account for it, a normal operating tolerance is built into the ECU. Good thing our engines are not carbureted!

Only when a misfire is significant will the sensor flag the ECU, and as Two Step said, the sensors are quite…sensitive. I had a solid CEL completely out of the blue a little over a week ago. Note : Blinking CEL is a severe problem / emergency. I took the car to the dealership. The car drove fine the entire time, minus the lights on the dash. The tech was frustrated to find nothing wrong (because they don’t get paid if they don’t actually fix anything, unfortunately). He checked and rechecked the ignition for 2 hours along with Honda’s online database. Cleared the CEL and sent me on my way. The car has remained fine since.

 

[Jester04]

That is just a noisy cyl, is this just cruising around not at wot? If its just cruising around nothing to worry about. Engines rock back and forth, resonance and other things can trigger a knock count when there is really none.

STFT are a bit high, and the LTFT are trying to compensate for it. So that could be cleaned up easily adjusting the tune.

 

[HondaFan777]

Hi Guys,

Been struggling with this for a few months with my 2022 Civic SI. I am not sure if these are false readings but they really scare me.... Defnitely considering trading in my car but I'd be at a huge loss. Acura was offering 21k for my civic @ 33k miles and I'm about to pull the trigger.

Symptoms:

1. High Knock count - 10 minute drive will quickly get 10 knocks then stabilize with 1 knock every 2-5 minutes
2. STFT1 is in the positive range. Highest i've seen it go was to +17% but stays between +1 through +10%
3. LTFT2 is stuck at -12%
4. Cylinder 3 has all of the knocks

The good:

1. No CEL
2. ~35mpg
3. No Limp
4. Making plenty of boost on demand (KTUNER TSP Tune)

Troubleshooting:

1. Double checked and tightened Front Engine Mount
2. Replaced stock intake with an Injen Cold Air Intake - Double checked installation for leaks
3. Swapped ignition coils to other cylinders
4. Swapped spark plugs to other cylinders

Your car is fine. Those are normal for a stock motor. You can drive yourself crazy looking too hard @ the Ktuner stats.

 

[Vito.FL5]

I would take the injectors out and check them just for peace of mind. if they are equalized just stop looking at the misfire counter and give her some beating lol.

 

[Shankmeyster]

STFT and LTFT2 are apparently not even used on 4 cylinder engines as those are for V motors that actually have 2 banks of sensors. If LTFT1 is reading high on the positive or negative end then there would probably be a problem. If you read up on the fuel trims, they are supposed to be within +/- 10% normally. You should only be going off of STFT1 and LTFT1.

 

[Jester04]

STFT and LTFT2 are apparently not even used on 4 cylinder engines as those are for V motors that actually have 2 banks of sensors. If LTFT1 is reading high on the positive or negative end then there would probably be a problem. If you read up on the fuel trims, they are supposed to be within +/- 10% in normally. You should only be going off of STFT1 and LTFT1.

And on these ecu’s STFT’s and LTFT are dynamic. Always compensating and LTFT does not become a static value.

Sponsored