street racer! sukuna hates asking teasing mechanic! reader for help
sukuna’s garage was an absolute mess.
oil-stained rags on the floor, random tools and parts lying around, dirty hands on the verge of pulling out every strand of hair on his head. he had been working in the garage for hours at this point.
so why - why - was nothing working?
he did everything he could. replaced the fuel pump. cleaned the injectors. put in new spark plugs. tested every sensor. all for nothing. the car sounded like a dream in neutral, but every time he accelerated past 30 mph, the damned car stalled out.
just his luck that his car would start having problems the night before a big race.
that’s why he’s been sitting outside your shop for the past twenty-seven minutes debating on if he should swallow his pride or go home and hope he can figure it out himself. sukuna’s phone dinged. a text from uraume:
talk to her
she’s the only one who can help you
he didn’t even bother responding to that. he doesn’t need anyone telling him what to do. you’re the last person he’d ever need help from… but he’s running out of time and options. so what does he do?
sukuna stared at the sign above the shop. his eyes followed down to the flashing OPEN sign, of course you’d still be open this late at night. his fingers drummed against the steering wheel. he doesn’t want to deal with you...
“fuck it.” sukuna grumbled before going in.
the bell above the door twinkled as he opened it. the shop was quiet. there was always a sense of calm this time of night in your shop — like the quiet after a storm. all the power tools had been turned off and put to charge. a soft hum of the overhead fluorescent lights.
“guess hell finally froze over, huh?” a wicked smile on your lips as you approached the front desk. your coveralls were halfway on, tied around your waist. hair pulled back into a curly bun.
“fuck you.” but sukuna was eating the words he said only years prior. claimed he’d never need you. said hell would freeze over before he’d ever ask for your help. boy, was he starting to regret that now.
“yeah, i’m sure you’d like that.” your smile widens.
you had noticed him sitting outside the shop, it’s hard to not notice a car like sukuna’s. his car sounded like a purring tiger when in neutral. anyone who knew anything about cars or street racing knew that sound was unique to sukuna and only sukuna.
he was the king of underground racing for a reason.
he exhaled slowly out his nose, trying to keep his calm. “i’m not in the mood.”
“yeah, i can tell. you’re all pouty.” you nudged him.
“i need something fixed.”
“oh?” you could almost laugh at how reluctant he sounded. like he’d rather blow his car up than admit he needs you to fix something. “must be pretty bad if you came to see little ole me about it.”
choosing to ignore you, “it stalls out every time i go past thirty.”
“always thirty? not twenty-five? not forty?”
“thirty’s the limit before it stalls.”
“weird.”
sukuna rolls his eyes. “i know it’s weird, that’s why im here.”
“wasn’t talking to you.” you turned around to head to the back. “bring your car to the bay, i’ll check it out.”
he drove his car around and into the service bay. he shut off the engine and got out. he opened the hood for you and watched as you did an inspection of the engine. “you replace anything?”
“everything.”
“everything?”
“spark plugs, sensors, fuel pump, injectors, wiring, i even changed the oil.” he listed off. “don’t know what’s wrong the damn thing.”
“your problem is electrical, not mechanical.” you explained. “you fixed everything that could have been wrong mechanically, but if the car stalls at thirty every time, the problem is electrical. mechanical problems aren’t exact, electrical are.”
you think for a second. “you said you replaced the wiring?”
“yeah.”
“the wiring for what exactly?”
he shrugged. “a few lights, the ecu, the radio.”
“you mean my ecu? the same ecu i built?”
the ecu is the engine control unit. essentially, it’s the brain of the car. the sensors around the engine send information to the ecu, and the ecu decides to how to run the engine accordingly. without an ecu, a modern performance car can’t run.
that’s why you built your own. most of your customers are street racers, so you learned how to build a standalone ecu to replace the factory made ones without the limitations. think about it like this: if the manufactured ecu was a computer, it’d be limited to medium graphics. which isn’t bad for casual use, but for someone who needs speed and clear graphics, it’s better to upgrade. or in this case, build your own.
you built and programmed that ecu specifically for racing. so why in the hell would sukuna go messing around with it?
“it’s in my car, it’s mine.”
“like hell it is.” your eyebrows furrowed. “i only gave it to you to spite you. it has been absolutely bliss knowing that every victory you have is because of me.”
god, he hated you. so, so much.
sukuna hated that you were right. he built his own ecu years ago but it was nothing compared to yours. he couldn’t go back to it, despite you rubbing it in his face. “so what? you want me to thank you? to devote all of my wins to you?”
“i want you to not touch my shit.”
“fine, fuck! i won’t touch it.” he exhaled a deep breath, trying to keep the last of his sanity. “just fix the car.”
“you’ll owe me.”
“how much?”
“a favor.”
of course you would never let things be easy. “what’s the favor?”
“mmm… don’t know yet.” you shrugged. “i’ll think of something eventually.”
“i’d rather pay you.”
“i don’t want your money.”
“what do you want?”
that precious, wicked smile returned. “for now? i just get to enjoy knowing you owe me.”
“you are an evil, little woman.”
“don’t forget genius!” you say pushing him aside to start working on the car. hands deep in the hood as you started to carefully unplug and unattach the wires connected to the ecu. you noticed many things wrong with it: the replacement wires were not the right type, the wires were not attached properly, and the high-performance MAP was corrupted.
sukuna is an idiot.
“you’re an idiot.” you say. “it’s no wonder the car keeps stalling out, it’s not even wired in properly.”
“but you can fix it?”
“duh, i built it.”
you spent the next few hours fixing everything sukuna did wrong. you threw out the bad wires he bought and replaced them with the correct wiring. after ensuring the wires were in properly, you got started on the fun part. instead of trying to fix the high-performance MAP, you replaced it entirely, giving sukuna an complete upgrade.
the corrupted MAP was decoding the signals wrong. instead of accurately decoding the temperature and boost pressure, it believed the engine was overheating and to prevent damage, it shut itself off.
the upgrade came from the tuning. sukuna sat next to you, watching closely. he said he wanted to know what to do if this happened again but your face quickly shut that idea down.
under no circumstances was sukuna to ever touch your ecu again.
with your laptop connected to the ecu, you began tuning everything. faster throttle response and ignition timing, higher rev limiter, controlled boost pressure, upgraded fuel mixture. you upgraded everything and made this one better than the first.
you had finished sometime around 2am. you were tired but felt accomplished and successful. you had exceeded yourself. closing your laptop, “alright, it’s done.”
“that’s it?”
“wanna go for a test drive?”
sukuna didn’t need to be asked twice. he buckled up and backed out. he slowly increased his speed, keeping a careful eye on the rpm. 10… 20… 30… 40… 50.
you did it. he exceeded the 30mph limit and didn’t stall. in fact, he felt better. faster, smoother, more agile. he had no doubts about the race tomorrow. he was going to win.
he dropped you back off at the shop. watching you get out and head back inside without so much as a thank you or a goodbye. but even if he wouldn’t admit it, he was glad he came tonight.
there really is no replacement for you.
BONUS SCENE:
it had been six weeks since you fixed sukuna’s car. six weeks since he owed you a favor. he’d never admit it but it was driving him crazy. every time he got a call or text, he felt a sense of anguish that you were cashing in on your ridiculous favor.
he’s had enough.
it was a bit past midnight. the service bay garage door were open. he pulled his car in and got out. “cash it in.”
you wiped your hands on a rag. “am i supposed to know what you’re talking about?”
“the favor.” he said like you were oblivious. “cash it in.”
“i haven’t thought of anything yet.”
“so think.”
“but i like knowing that you owe me.”
“y/n.”
ooh, he’s getting increasingly irritated if he’s saying your name. let’s think… what’s the one thing sukuna hates most in this world? people, yes. but other than that? sappy, physical affection. it irks him beyond belief.
“you’ll do whatever i ask?”
he’s already suspicious. “within reason.”
you stand, holding your arms out wide. “give me a hug.”
he’s silent for a moment. not in shock, just processing that that’s your favor. he spent all this time stressed over… what, a damn hug? he wasn’t going to do it anyway, but it’s the principle. “no.”
“you said whatever i wanted.”
“i said within reason.”
“it is within reason.”
“i’m not doing it.”
“then you can live with the fact that you owe me for the rest of your life.”
he wanted nothing more than to wipe that smug look off your face. your little shimmy as you tried to entice him to come closer. you were dangling this favor over his head like a mistletoe. he just wanted to be done with you. reluctantly, “fine. i’ll do it.” he pinched the bridge of his nose as if he was bracing himself for the hardest thing he’s ever done in his life.
he took a few steps to close the gap between you. he watched your arms wiggle as you smiled up at him. it pained him to wrap his arms around your torso, hands lingering at your waist. it was stiff and uncomfortable and possibly the worst hug ever received.
could be a new guinness world record.
after a moment, he pulled away quickly, as if touching you would give him some rare, contagious disease. “never talk about this.”
“aw, and i thought we were having a sweet moment.”
“i hate you.”
“likewise, honey.”
in truth, you never had a favor in mind. you just wanted an excuse to see him again.
as promised, the mechanic version. not all that confident in the banter but i hope it’s decent. thanks for reading, you’re so angel baby face 🙃 @keipurra











