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

cameron.hill

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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
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Sounds to me like crud from the bottom of the fuel tank. How that could interact with a tune is another discussion.
 
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cameron.hill

cameron.hill

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Sounds to me like crud from the bottom of the fuel tank. How that could interact with a tune is another discussion.
Thanks for the reply, my man. I hope it was just because of the low fuel
 

Drake

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Thanks for the reply, my man. I hope it was just because of the low fuel
I doubt the fuel level would be the issue since you said this occurred after you filled up the tank. Also, once I probably drove 20 miles with the fuel light on and nothing strange happened after I found a gas station.
 

joshhjackson2112

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Were you listening to music while pumping gas? Sometimes my car starts kind of rough but I am pretty sure it's cause my stock battery is shyte and needs to be replaced. Anytime I turn on a light or infotainment without cranking the car, it takes an extra second to fire up. I wouldn't think it would be because of the low fuel. I have run with the light on until the range read 9 miles.
 


EconoBox

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These cars have a 12.39 gallon tank. Even with 0 range left I've never put more than 11 gallons in the car. They are set up that way to keep people from allowing the car to run dry. This avoids having to deal with air in the direct injection system.

Honestly, it sounds like a low voltage issue which has been mentioned already. Just keep an eye on things but I doubt it's anything to worry about.
 

amirza786

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I doubt the fuel level would be the issue since you said this occurred after you filled up the tank. Also, once I probably drove 20 miles with the fuel light on and nothing strange happened after I found a gas station.
Well here's the thing. When you let your fuel levels get to low, if there is crud at the bottom of the tank it can cause some issues if it gets stirred up, but it should pass. Use a good quality fuel cleaner (like Chevron Techron fuel injector cleaner) and finish one tankful, the issue should clear up
 

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whens your next video come out about the issue. your video made me pull the trigger on a 1.2 ktuner, but im just gonna run factory normal/19 sport w/ rev hang delete basemap
 
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cameron.hill

cameron.hill

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whens your next video come out about the issue. your video made me pull the trigger on a 1.2 ktuner, but im just gonna run factory normal/19 sport w/ rev hang delete basemap
I could post it tonight, but I think I’ll wait till tomorrow. I’m gonna be much more consistent with my videos now. At least twice a week.

also, good to hear! Thats actually the one I am running right now. I didn’t want to mess with the 23 psi basemap after the misfires
 


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Sounds to me like crud from the bottom of the fuel tank. How that could interact with a tune is another discussion.
Just to dispel the myth out there... one that I believed for years also... there is no crud in the bottom of your tank. I dropped my tank once on a 6 year old car to install a walbro, and the inside of the tank looked brand new. Nice and clean, no gunk. Just fyi.
 

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Just to dispel the myth out there... one that I believed for years also... there is no crud in the bottom of your tank. I dropped my tank once on a 6 year old car to install a walbro, and the inside of the tank looked brand new. Nice and clean, no gunk. Just fyi.
I recall upgrading the fuel pump in my old WRX and there was a bit of dirt in the bottom of the tank, but nothing to be concerned about. Certainly nothing that would get past the filter attached to the fuel pump. On a basically brand new car, there better not be any noticeable dirt in the tank unless you get fuel from some shady gas station.
 

icemansi

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I could post it tonight, but I think I’ll wait till tomorrow. I’m gonna be much more consistent with my videos now. At least twice a week.

also, good to hear! Thats actually the one I am running right now. I didn’t want to mess with the 23 psi basemap after the misfires
Same situation here. I watched your video as soon as it ended pulled up tsp website and pulled the trigger on 1.2v with the tune!
 

SDAlexander8

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His car is way too new for there to be any significant junk at the bottom of the fuel tank.

It may be time to look into a custom tune. You are introducing a lot of performance mods to the car in a short amount of time.
 
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amirza786

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His car is way too new for there to be any significant junk at the bottom of the fuel tank.

It may be time to look into a custom tune. You are introducing a lot of performance mods to the car in a short amount of time.

Are you using 91+ octane?
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
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