Need help tuning 2006 SI.

[stereokid101]

Can anyone help me tune my 2006 Civic SI? It is completely stock other than a K&N drop in airbox filter. I have a FlashPro and can take datalogs with no issue. Any help would be appreciated.

[EFICU]

I can help you with it if you'd like. Do you have any future mods planned, or are you planning on running this current setup for the foreseeable future?

[stereokid101]

I would appreciate it. I do not currently have any plans except to fully rebuild the motor as of now, and after that is complete I will be purchasing a header, catback, and most likely a supercharger. I am running a custom tune currently, however I am having issues with a misfire code on all cylinders only under heavy acceleration after topping out at a minimum 3rd gear, if not 4th, whether on the custom tune or the "stock" tune via flashpro. That misfire code goes disappears if I do not do the above mentioned things. I am attaching the tune that I am currently using. Also, both O2 sensors are new OEM sensors, I have also replaced both cams sensors, crankshaft sensor, fuel pump and assembly, spark plugs, coil packs, and both VTEC solenoids. Thank you again for the help.

[EFICU]

I see. Do you have any datalogs showing those issues and some general driving?

Also, I am guessing this calibration wasn't built for you right? You got this from someone or a forum? I feel like I've seen the name on this file before is why I ask.

[stereokid101]

I'll tune the car back to stock and at that point get a datalog for you. Yes, that tune was the 6th revision from Etunez made specifically for me, and the misfire issue didn't start for months after I started using the final tune. The tuner had mentioned that I either had a air leak somewhere or a bad O2 sensor, so the O2 sensor has been replaced, but he had mentioned that he was adding additional fuel for that reason.

[EFICU]

Gotcha. Then make a datalog with the current tune in the car from them. If he kept adding fuel, with the new sensor it might be really rich. Take it for a 10 minute drive, and make one wide open throttle (WOT) pull in third gear from 2500-8400 so we can see how it all looks. Then we can formulate a game plan.

[stereokid101]

I used the current tune (Rev6) from them and got 2 pulls in 3rd as requested. I have attached the datalog. Also, I didn't replace the O2 sensor until after I started having issues, even though at the time of tuning I had replaced both O2 sensors within 15k miles, but I ordered another one with the assumption that Bank 1 was bad. The fuel injectors were also replaced within the last 15k miles with OEM 310cc injectors, ordered from honda.

[stereokid101]

I had the check engine light flash in atleast one of those 3rd gear pulls, I believe 3rd gear, around 7000 rpm and the light went away when I let off the throttle. That seems to be the time in which the misfire codes show up.

[EFICU]

Yeah something is definitely not right mechanically. Your fuel injectors are maxed out physically at 7720 rpm when they hit 100% duty cycle, though anything above 90% is considered by most to be maxed which your is at 7000 rpms. At 8064 rpm your misfire issues come on and register all cylinders as a culprit. Even a full bolt on 8th gen rarely reaches 100% duty cycle, so you shouldn't be anywhere near that. In looking at another 8th gen I am working on with a stock intake right now, his duty cycle is at 74% at 7740 rpms. So something isn't right somewhere. Your AFR is just fine there, so it's not like it's super rich causing the extra duty cycle. If it was super rich I could see the duty cycle being high, but yours is fine and still reading a maxed duty cycle

Do you have any background on the car? Do you know if it was modded before you got it? Have you done anything with the fuel pump or fuel system at all?

I don't recall seeing such an issue. Once your car registers the misfire, it kills the fuel trims and they stop working from there on out.

As far as the calibration, I don't see anything sticking out to me to cause the issue. But if you want, we can try my basemap for a stock 8th gen and see if the issue persists. Otherwise, it needs to be looked at and diagnosed because something isn't right.. Since you're replaced the injectors and the o2 sensors, something is causing an issue in the fuel system I would have to imagine.

The lightweight clutches have been known to cause misfire detection issues on 9th gens, but I haven't heard of it on 8th gens.

[stereokid101]

I wouldn't mind trying that basemap, but it now has 258,000 miles on it. I haven't gotten around to replacing the clutch or flywheel yet. I have also tried 2 completely different fuel pump assemblies with the same issue. I doubt it was modded beforehand but I cant be sure. It was a 1 owner and when I test drove it the vtec crossover and rev limiter were factory. Is there any possible way that a bent fuel rail line under the hood could cause that? The only thing I can imagine with that is where fuel could be partially restricted from getting to the injectors.

[EFICU]

Okay, it says in your calibration you have the clutch and flywheel upgrade is why I thought that.

Everything in the exhaust is stock? I'm wondering if you have a bad catalytic converter. If the cat is original, then it might be extremely clogged or damaged. You've literally replaced everything, and still have the issue. The only other thing could be the cat. It has the stock fuel rail on no aftermarket regulator right, completely stock?

Comparing your calibration and mine, I would be nervous to have you try mine when comparing fuel tables. Yours has 30% more fuel than mine at 7000 rpm which makes sense as to why the injectors are maxed. I'd hate to have you run mine and have it go lean.

I would recommend pulling the cat and looking at it. See if there is any visible damage to it or not. Generally a blockage would make the car run richer I would imagine, not cause more fuel needed to hit target and max the injectors, but you've literally replaced everything.

You can turn off the misfire detection in the tune, but I don't recommend it. Especially when you have an issue of some sort going on causing those to record a misfire. The knock sensitivity tables have also been altered, so you may be getting knock that we aren't seeing either.

The only thing we can do to lower fuel demand on a WOT pull is have you run on the 0* cam angle all the time until you get the issue sorted. It wouldn't be powerful, but it might stop the maxing of injectors and stop the misfires from happening until you get it figured out.

[stereokid101]

It is the stock fuel rail with no modifications, but it got bent a bit when replacing the injectors, so that I'm pretty sure less fuel was able to pass into the rail itself. If you could send over that tune I'd like to check it out. The exhaust is 100% factory.I can have the car flash the check engine light with the Flashpro when it misfires, so I can enable that. I have already ordered a ... exhaust, so it wont be long until that arrives either way. Will I need a new tune after rebuilding the motor and installing the exhaust?

[EFICU]

Yeah then I would just wait until you get the test pipe and then reinspect. If you were having the issue before the injectors, then I wouldn't imagine a slightly bent rail wouldn't have caused it. It may not have helped, but not caused it.

I would say you will need a new tune, or at least clean up the tune for the test pipe. If the test pipe clears up the issue, it will 100% need some substantial changes because the fuel delivery will be very different. With the test pipe, you should be in the 80% ish duty cycle. Are you doing a test pipe, or a race header? Either way, if you put the test pipe or race header in and still have the same issue, then something must be bent or damaged in the fuel system.

My file won't do you any good at this point. The values are so cranked up in yours mine would be really far off. I can help you tune yours on the 0* cam angle if you want while you try to get it fixed. It won't make a lot of power and won't be much fun to drive, but things would be a little safer as the 0* cam angle doesn't demand as much fuel and shouldn't cause maxed injectors.

The new engine should definitely be tuned. You're going through all that effort to put the engine in it would be good to tune it.

[stereokid101]

I actually didn't have the issue before the injectors were replaced, and I just fixed the fuel rail bend. I am installing a race header, so the cat wont be an issue.What I'll probably do is tune the car back to stock, then go for a drive and see how it goes. Thank you for your help.

[stereokid101]

I used the preloaded "stock tuned" tune from Hondata, and I didn't have any check engine lights or misfires. Using this same tune previously I had misfire issues.I took a datalog as well as watched the injector duty cycle with the Hondata app on my phone and it didn't get above 90% even at 8400rpm. Maybe the fuel hose resolved the issue. I'll attach the datalog if you have the chance to take a look at it.