Hi all.Again me with an update to my post. Maybe now someone can shed more light on me and tell me what would you do in my situation.
Update 👇
Maybe someone have an idea what could be wrong with my jazz. Firstly car jerks a lot when shiffting or if i drive steady and apply more gas it jerks.
When accelerating and putting car in neutral rpms are fluctuating and eventually evens itself out.
And other one occasionally is when car is cold and i start to drive shiffting from 1st to 2nd and applying gas car acts like someone applyied handbrake (hesitation) and after like a second goes off again.
Sparks changed, air filter cleaned, premium fuel, coils checked, no codes, gearbox oil, engine oil and filter changed last year.

One week later after this post was created, today...
UPDATE: just today i changed engine oil (service due) and it's really strong smell of petrol... Could this all be linked!? Spark plugs however, i changed 2 months ago, 60K and i showed them to mechanic i know and he said they are fine.

When disconnecting from battery and connecting after couple hours, car runs better till relearns i guess.

Forgot to mention Jaz Ge 2013 60k miles but started long time ago and got more noticeable.

Thanks 🤟

 

Sounds like you've either got a problem with your electronic control module/computer or something's messing with it..
It's an awful longshot, but coils could be generating radio interference. Are they original?
A few other things come to mind, but they don't fit with the car running better after unhooking the battery.
It'd be nice to check out the injectors to make sure they're doing their job of atomizing fuel and not leaking.
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Any electrical extras or modifications? Maybe you drive around with something plugged into your OBD port all the time? I've never dealt with that issue, but I've heard of it.

 

Thanks you for response. Well i got suspicions worn piston rings (but doubt it), some people say simmilar issue as mine, changed coils and problem gone or injectors... Well i would need to take it to garage or to Honda. But don't know where to don't strip my pockets. Neither do I'm a fan to start throwing new coils at car,injectors ect. Want to know what others would do!?
Car doesn't have any upgrades and nothing in obd port.

 

An update today i changed engine oil, cleaned throttle body and again properly cleaned egr. Car runned smoother but that always happened before, when removing from battery and my passenger managed to capture my rpm float.

 

An update today i changed engine oil, cleaned throttle body and again properly cleaned egr. Car runned smoother but that always happened before, when removing from battery and my passenger managed to capture my rpm float.

 

The issue with assuming it's piston rings is that you say the car runs better after disconnecting the battery. Piston rings would be a constant problem. Or, if minor, it would get better as the engine warms up to operating temperature/worst when starting first thing in the morning. And a car with that problem may run worse after a battery disconnect because the computer is no longer compensating for compression loss. battery disconnect eliminates stored sensor data.

If it runs better after disconnecting the battery, then the data the computer has stored for making your engine run best is incorrect. From that you should be safe to assume an electronic fault. But if you don't have any stored codes, with how significant the issue you described is, there should be a problem with your car's computer, or something interfering with it. Do all the symptoms go away after disconnecting the battery for a while, or just some of them?

Without more data, to avoid wasting money, I'd recommend a mechanic first. It's hard to communicate the whole driving experience online. If I could get in it myself I might have a better idea.

I noticed in your video that some lights were on in your dashboard. You turned off traction control, but I think you lost traction for a second and got an abs light too. I couldnt tell if there were any other lights, but if so, they may be relevant.

Going off of just what I've read and understand so far, I'm leaning towards ignition coil or ecm malfunction.

 

OP has a lot of changes to the car. Such as exhaust, some air box delete mod, K&N filter.

Not sure what I am suppose to be seeing in the uploaded video there.. Everything looks normal-ish as far is RPM meter is going.

Maybe check your MAF sensor from oil contamination from the K&N filter re-oiling.

 

Thanks for an answer.
After battery is disconnected not all simptoms are going away... Car jerks less on gear changes, rpm float is persistent and car feels more alive.

The lights: I do turn off traction control yes and i was in neutral to film rpm float so ECO sign showed up.
Again thank you for a great response!

 

I bought car with K&N inside there was no issues, i did remove back box and i think after i noticed rpm float as car is louder Sensor last time some people said i cleaned it but before cleaning it looked better than new, didn't make a change. I try not to mention normally that i have k&n as i think it's a myth with oil landing on maf.

As per video... Bad quality but after taking out from gear rpms float, dip...

 

Aw man, you left out some important information! Not cool. Thanks for the heads-up @mykizism

There are a couple tricks to home diagnostics. The most loathsome of which would prolly be resetting to stock. I hate it, but it can be really educational.

So you've got an aftermarket air cleaner, and the car ran just fine with it. But maybe it was clean then. The car knows how to act when the stock filter is dirty, but the aftermarket one, not so much maybe?
Why not try taking it off and cleaning it vs. re-oiling. Maf cleaner spray is plastic safe, and I've recently found it to be pretty effective for cleaning a synthetic mesh filter (vs. air filter cleaner spray)

Is K&N telling people all they need to do is re-oil those? I suppose they'd be the only ones qualified to say. I remember reading a piece by them defending against claims that some of their filters cause check eng lights. Their response was that they're the only ones with the technology to properly test their filters, so there's no grounds for such accusations Using it tests it

​​​​​​Yeah, start there. Clean it, blow it dry, re-oil it if you're supposed to, make sure it's dry before installation.

What's this about a back (black?) box and some correlation to RPM float?

I won't tell yuh to reset your car to stock if you don't have the parts to do so. I once tried to get a motorcycle mechanic to rejet a carburetor I swapped on my bike for another model's. They jetted it to stock for the bike the swapped carb would have originally belonged to gave it back to me. Took my money and showed me the door
I'll take some time to think about your symptoms in light of the new info.

 

I'm personally surprised by your lack of a stored code, but others might not be. I'm going with the theory that one of the mods is at fault, and most likely something to do with your intake setup. keep the mods, elaborate on the back/black box, and check them over. If you say there was no trouble with them at the start, who am I to argue? But an intake air issue would fit with your symptoms, and cleaning the filter/checking fitment of your intake system is basically free. Unless you think the original fuel injectors or coils may be starting to show their age.

You could prolly pick up the needed data by reading fuel trim with a scanner, torque app, whichever thing. I think I participated in a thread months back where I pulled a TON of fuel trim data for some dude to compare to his car. I think his problem was EGR functionality, but I'm pretty sure I captured other data with it, lemme check.
Yep. Heres the Link

And as always, throw in a valve adjustment and check torque on your spark plugs Your Fit will always be grateful for those two.

 

The point is there are changes to the car that were not mentioned when asked. K&N filters are fine for the most part and oil landing on MAF is not a myth its a fact when end users over oil the filter and do not follow proper procedures. Many users of K&N filters with MAF sensor cars have experienced check engine lights due to improper procedures when servicing the filter. This has been well documented across many boards for decades now.

You got it bud



Over all I think OP car is fine.. and is technically not misfiring at all but idle dropping and compensating as normal.

If the car was actually misfiring there would be stored code.. the ECU will know if it is or not.

With modifications to factory air box, there are unknowns associated with it. As the factory air box is well designed and has little margin for improvements except changing to something that has been dyno tested such as an AFE intake system.

Other users on clubjazz.org have told the OP that the car is behaving normally as these engines have those quirks. Posted here. https://clubjazz.org/forum/index.php?topic=16204.0

Without a proper scanner and looking at actual data everyone here is taking a blind guess.

 

I usually use K&N cleaner, rinse it, dry it, reoil. As per instructions.
Today i went to honda independent garage and they wanted to throw new throttle body and coils for now i turned arround. In future, hopefully soon I'll take it to Honda for diagnostics.
Well known mechanic follows this and said to try engine coolant temp sensor. I might try that one as its not expensive but looking at honda manual looks like coolant needs to be drained.

 

Well i could try and throw any stock air filter at it just for sake of it.

 

I do have a scanner tool. Fuel trims look fine as much as i understand from them.
I understand it's hard to diagnose something here without looking at car.
Thanks again to everyone tho.

 

The shops you went to all have recommended the proper parts to replace in trying to fix your hesitation.

The problem you are describing sounds to me like you are trying to accelerate then it feels like you hit a wall where it slightly hesitates and bogs down .. does that sound about right?

If that is the feeling you are getting.. all above recommend items sound about the right course of action..

However a few test can determine if those devices are failing or not. such as looking at throttle position to see if the throttle body it is consistently showing a constant signal or fluctuating. If it is fluctuating that is not good and the TPS signal is jumping and landing you in incorrect spots on the fuel map. That will cause hesitation or bogging.

The ECT engine coolant temp can also cause the same feeling if the ECU is compensating fuel trims for coolant temps that are not correct. There is a table for ECT and fuel trims that when engine is at a certain temperature it gives x amount a fuel. If that is showing bad signals it will jump around on the fuel trims causing hesitation or bogging.

Same with MAF.. if its not reading the air mass properly it will give false signals to x amount of trim during a specific throttle position.

 

Thanks for the time and effort to answer.
Is there anyway i can check these readings with quite cheap obd tool!? What i should look out for!?
P. S Interestingly drove this morning and rpms not fluctuating so much after adding redex in existing half a tank of E5 and toping up one day later with 15l of E10, mystery!

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@mykizism Absolutely killing it!
I knew, and forgot about watching for voltage oscillations from the TPS, but had no idea that the coolant temp sensor could factor in. Weird, because there's obvious compensation on cold starts, but I never would have thought of that! @Hopipola I don't know if this thread is providing what you're after, but I'm liking it, man.

I know you can use a multimeter to test signal from the throttle position sensor. You just have to find the right wires on the TPS. Not sure for the Fit, but I recall those signals being in the 0-5 volts range. At a steady throttle position, you should get a steady reading, and it can be done at idle.
I'm gonna guess the coolant temp sensor does the same thing. For your fault it should be about the stability of the voltage readings more than the voltage itself.

I've taken a liking to torque pro. you can put up sensor voltage readings, temp, throttle position. I don't know how much latency there is between changes and the app, but if you can run a graph style graphic, it should show any goofery.

While troubleshooting our tacoma some time back I checked the throttle body/tps in a semi-unconventional way. bought a junk yard TB off ebay for $35 and gave it a cleaning, ran it. Figured if it had problems, they at least wouldn't be the same Now I've got an extra TB.. They were both completely fine. But I liked the action of the throttle plate on the junkyard one better. More snappy.
Unexpected perk!