P0301 Misfire on cylinder 1

[Syntek]

Good luck lol. They sit below the integrated IM assembly very close to the piston heads.

Fucking wonderful.

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[kcarne]

I'd be worried they want to send your ECU in, see it's been flashed, and they tell you to kick rocks (as far as your warranty goes). It's why I'm personally hesitant to tune, I have a 8yr 120k warranty to keep intact. Best of luck and keep us posted as to what you find out!

 

[Design]

For a mechanical issue I doubt they look unless the misfire is determined to be related to the control module. Though they may try to duplicate the error and hook up the ECU. It shouldn't really show much as long as the OP allows the stock parameters in the ECU to calibrate. The only time it may come up is for a catastrophic failure where Honda may want to look at freeze frame data, which is stored in the infotainment. But I think they can only look back 30 seconds or so. That hasn't been confirmed but is the prevailing theory among tuners.

Case in point: We had a member here over-rev their hatch on a tune. And the freeze frame data showed evidence of tampering.

 

[Syntek]

I'm honestly not worried about the warranty to be quite frank. I knew the consequences and risks of running a tune and have fixed my own issues and problems that I have caused but it honestly feels like this has nothing to do with the tune itself. If anything it's more annoying and frustrating to me that I can't pin point exactly what it is so I can take it upon myself to fix or if it's something that legitimately just malfunctioned due to a faulty part. In any caze I've been driving around stock today and yesterday and I'm going to try the differnt fuel and fuel system cleaner. If that doesn't help then I'm making an appointment with Honda and telling them what I've done in regards to diagnosing and repairing and see if they can do the additional tests for it.

 

[Syntek]

Okay, update. Woke up this morning expecting the car to misfire and run like ass.... it didn't. Aside from very minor rough idle, lasted for about 4 seconds then it smoothed out to virtually nothing. No error code came up and didn't go into limp mode and drove off just fine. I'm still on the same tank of gas and haven't added any fuel cleaner yet. Lol?

 

[Dario1101]

Days like this is where I wish we had X-Ray vision to see all the little internal parts of the car and see where the problem is.

 

[Syntek]

Dropped off my car today at the dealership, will find out tomorrow afternoon or Monday morning on what the potential problem is.

 

[Syntek]

Update from Saturday: Checked wiring hsrness, no issued there. . Checked coils + Sparks, everything normal. Did compression test came back normal. They're going to test injectors and valves next on Monday. The block is fine so that's a great sign.

 

[Syntek]

Update from today:

Injectors came back normal.
Valves were adjusted and came back normal.

Waiting to hear back from Honda directly on what to do now. I have a feeling my dealership doesn't know wtf is going on with it either.

I don't think they fully tested the valves, my next guess would be that. Will hear back tomorrow.

 

[Design]

Has it misfired since flashing back to stock?

 

[Syntek]

Has it misfired since flashing back to stock?

Yes

 

[Design]

Only other thing i can think of is carb deposits on the intake valves. Which would be odd on a car this young. Good luck with the dealer.

And props for keeping us posted.

 

[xcoreflyup]

Only other thing i can think of is carb deposits on the intake valves. Which would be odd on a car this young. Good luck with the dealer.

And props for keeping us posted.

I am not surprised

I have a catch can on my HB sport. My car has 111xx miles now and I only have the catch can for the last 1500 mile or so. There is a thick layer of oil in the can already.

 

[Syntek]

You may be right on the intake valves. Nothing is really cleaning the intake valves since our engines are DI. If it really is that and they clean out all the gunk or replace the intake valves, I think it's time to invest in a catch can.

 

[Acraig3]

Okay lads, I'm trying to figure out what the hell is going on exactly with this car and see if this is something simple I can fix on my own or if it's out of my control/fault and I need to warranty it out. (I've been tuned most of the time + running K&N SRI)

Been having a misfire on cold start only. These past two days it's gotten bad enough that the CEL is now flashing on/off and going into limp mode. It takes restarting the car after it warms up a bit to get it going normal again. It's been doing this on both stock and tuned base maps. The car ONLY misfires on cold start

First thing I did was inspect and change the spark plugs at 30,000 miles. The plugs looked normal and not fouled, no signs of soaked sparks or white ash, burning oil or carbon deposits. Didn't help. Next step is I swapped the coil with cylinder 1 and 4 and flashed the car back to stock and drove around for a bit and went home. Following morning I still got the same symptoms and P0301 still came up so that rules out if it was the tune or the coils.

Not really sure where to go from here now or what to inspect before I call it quits and just have Honda look at it. My next step is to probably throw in some concentrated full fuel system cleaner and going to Chevron (I use shell 91 80% of the time) to rule out if it's gas related or not.

Any ideas? Thanks

Side Note: Big shout out to @dc2turbo for taking the time to look at my datalog. Everything looked normal to him.

I would recommend going to O'Reillys and picking up some BG's 44K. I had misfires on my 2003 MDX, mind you it had 190k on the clock. But it cleared up my misfires as I had dirty injectors and fuel system. Chevron is good, just had better luck with 44k

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