My 2020 Si misfired.. twice, using 19.5/23 psi basemap

Dirtychonies

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I was using the 19.5psi starter map from Ktuner and was low on gas. I probably had around 28-30 miles left (says the car), and went to the gas station to fill up. Yes, obviously with 91, forever and always.

After I had filled up, I turned the car on and it had quite a rough start. My girlfriend immediately noticed something wasn't right and we both looked at each other. I listened closely for a few seconds and everything seemed fine, so i turned the car off. I then turned the car on a second time and it did it again. I have the MAPerformance street exhaust, which enhanced the sound AND feel of the rough start both times. I let it idle for about a minute while my anxiety went through the roof as I listened intensely. I turned the car off and on a third time and it started up fine.

Could this have been because I was low on gas? I wasn't THAT low on gas, but the gas light ahd been on for about 7 or 8 miles before I could find a gas station. The car has not done this since, and I am about to upload TSP Stage 1 after work today, which I hear is much better and safer than the 23psi basemap.

Let me know what you guys think. Thanks
I had a missfire at around 13k miles with the dual Ktuner map. I had a bad fuel injector #3 and ended up finding out down the line its a common problem. Fortunately, my car was still under warranty.
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Syntek

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take to dealer to further diagnose, had faulty injector in my old 2016 EX-T that got warrantied out even after I had it modified.
 

SDAlexander8

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Thanks for pointing that out. I didn't look at what mods he had (DUH!). Definitely the PRL CAI might need a tune if it's not included in the TSP Stage 1. Also you don't list DP, so I am assuming you have a CAT-back, which would not need a tune
He has a youtube channel for his build. He’s doing a good job showcasing all of the mods and giving honest opinions about them. You should check it out.

He lives in Cali. I wanna see a race with the IS350
 

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I had a missfire at around 13k miles with the dual Ktuner map. I had a bad fuel injector #3 and ended up finding out down the line its a common problem. Fortunately, my car was still under warranty.
which dual map?
 

amirza786

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He has a youtube channel for his build. He’s doing a good job showcasing all of the mods and giving honest opinions about them. You should check it out.

He lives in Cali. I wanna see a race with the IS350
Haha no racing for me. I've been doing a good job restraining myself when someone next to me is impatient at stop lights. I will check out his channel. Does he use the same username for his Youtube Channel?
 


Hollywoo0220

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I was using the 19.5psi starter map from Ktuner and was low on gas. I probably had around 28-30 miles left (says the car), and went to the gas station to fill up. Yes, obviously with 91, forever and always.

After I had filled up, I turned the car on and it had quite a rough start. My girlfriend immediately noticed something wasn't right and we both looked at each other. I listened closely for a few seconds and everything seemed fine, so i turned the car off. I then turned the car on a second time and it did it again. I have the MAPerformance street exhaust, which enhanced the sound AND feel of the rough start both times. I let it idle for about a minute while my anxiety went through the roof as I listened intensely. I turned the car off and on a third time and it started up fine.

Could this have been because I was low on gas? I wasn't THAT low on gas, but the gas light ahd been on for about 7 or 8 miles before I could find a gas station. The car has not done this since, and I am about to upload TSP Stage 1 after work today, which I hear is much better and safer than the 23psi basemap.

Let me know what you guys think. Thanks
You can be experiencing a variant of things:

Your exhaust is going to DRONE the exhaust sound more than stock
Since, you drove to the gas station and stopped - your stock intercooler could have been so warm (after sitting) that the manifold was intaking warmer air; thus, rough combustion.

Have you monitored your Fuel Trims? You may be running a bit lean at start-up and thus your "misfire" sound?
Is your MAF stock or Race/Street?

You are pushing more exhaust out - but at less velocity than the stock piping size.
You may want to get a FULL Custom tune.

So many questions....
 

amirza786

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SDAlexander8

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Haha no racing for me. I've been doing a good job restraining myself when someone next to me is impatient at stop lights. I will check out his channel. Does he use the same username for his Youtube Channel?
Do it for Dale!
 

amirza786

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