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Discussion Starter · #1 ·
Discussion Starter • #1 a moment ago
I’m fairly new to the sti world. I’ve had my 2017 wrx sti for about a year now. Mods:
Invidia catback exhaust
Cobb high flow catted downpipe
Cobb air intake
Walboro 450 fuel pump
Top speed 1050x fuel injectors
Cobb fuel rail line kit
Cobb fuel pressure regulator kit
Cobb fuel rails
5th gear Motorworks street tune
I recently took my car to 5th gear due to a misfiring issue after having my fuel system and downpipe installed poorly at a different shop. I was running the Cobb stage 3 OTS map and 5th gear fixed the issue in a day and I got a street tune while they had my car because OTS maps are not the best. My car has been driving amazing for about 2 weeks since I got it from them and a couple of days ago I got the first overboosting issue and check engine light came on throwing boost limit exceeded code. I was doing a pull from first gear and stopped at about 130mph in 5th gear and a few minutes later noticed the engine light. My new peak boost was 24 psi and it is tuned for 20 psi. Since then anytime I go over about 60-70% throttle or floor it the boost builds very quickly and it over boosts and seems to backfire or something I’m not sure what you would call it. But it does it in any gear and anytime I accelerate hard enough to get to 20psi before shifting and the boost will keep rising. I really have no clue what could be causing this because the tune has been running fantastically for 2 weeks idk why I’d just now get an issue if that was the problem. I also still have the stock boost controller. Any help would be greatly appreciated! Thanks!
 

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Super common on the ej with an intake and turbo back.

I'd reflash that cobb stage 3 map with the appropriate wastegate option for overboost issues and see what you get.
 

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Discussion Starter · #3 ·
Super common on the ej with an intake and turbo back.

I'd reflash that cobb stage 3 map with the appropriate wastegate option for overboost issues and see what you get.
I’m not running the Cobb stage 3 tune anymore I got a street tune from 5th gear when they fixed the fuel system and put one step colder plugs in it so I can’t reflash it.
 

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The map notes show they support those mods unless there is something else there. Your ap can hold multiple times, or they could in the past.

Either way the tune is bad and needs addressed. If the cobb stage 3 does in fact cover your mods I would start there.
 

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Discussion Starter · #5 ·
The map notes show they support those mods unless there is something else there. Your ap can hold multiple times, or they could in the past.

Either way the tune is bad and needs addressed. If the cobb stage 3 does in fact cover your mods I would start there.
I just started it and popped the hood and there was a fuel leak could that be causing the overboosting?
 

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Per your pm about why it's over boosting. I'm going to guess the overboost is from improper wastegate tuning and cooling temperatures as the end of summer fades out as fall approaches.

It'll just get worse until it's fixed. The more you drive it the more likely you are to damage the piston. I don't know why you need colder plugs, if their tune is that bad they asked you to run colder plugs for an intake and exhaust with that much fuel availability I'd question their methods personally.

I just double checked cobb and unless I'm missing something the stage 3 for your car is those mods specifically unless you have something not specified. I'd try the low wastegate stage 3 map by cobb and factory plugs.
 
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