New headers installed but car wont start
 

Hey, so I just recently got a 2013 brz back in March and finally was able to start modifying and just now installed invidia n2 fatback, front pipes over pipe and tomei uel headers. And when I go to start the car too see how it sounds, it starts but dies literally right away. And something doesnt make sense. The car was running perfectly fine before and all I did was change the exhaust. Do want to note that when I tried to disconnect the o2 sensors (wire connector side) when troubleshooting it would run and stay running but after a few seconds the rpms would start to jump between 1000-1500 rpms which I would say it's normal since no o2 sensors were connected. Also did put on some anti sieze on the threads of the o2 sensors and maybe some got on the inside without me knowing but none of this makes sense and tried to find something online and absolutely nothing. So some suggestions would be nice

Did you use new gaskets and torque everything?


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Check your MAF plug. Just disconnect it and plug it back in.
Also, did you apply a tune to the car in anticipation of the headers? The tune could have an issue if you did.

Also check that you didn't disconnect the cam sensor. It's in the immediate vicinity

I used new everything from gaskets to hardware and torqued everything.

And where would the cam sensor be located? Will definitely take a look. And no I didnt install a tune yet. I was thinking it shouldn't have an effect on it that much since I've seen tons of people run without one or at least be able to start it lol. But I was thinking that could he the issue somehow

So you don't plan on running a tune with the full exhaust setup?

If we assume that you did the minimum required work - didn't disassemble anything unnecessarily - the smart money is on some sort of electrical issue.

It doesn't need a tune to run. Don't sweat that.

Can you write up a list of exactly how you prepped for the job and what you took apart? That might help us come up with ideas. You might even have an 'oh shit' moment on your own.

This.

I suggest you take off the underneath plates and look and rethink what you did. I figure something needs to be plugged back in - what - :iono:


humfrz

i assume you disconnected the battery before doing the stock header removal and installation of aftermarket?

Try an ECU reset

I do plan on running a tune on the car shortly to get the most out of this setup. was planning on doing that next but now i need to fix this problem first then get the tune next

everything i took off was the shield thats right under the headers, then started by disconnecting the o2 sensors up in the engine bay and took out the header. then started to work my way back. and when it came to installing everything back in i started with the headers and also worked my way back. but no i didnt disconnect the battery. but when i was troubleshooting what was going on, i did disconnect the battery to reset the ecu but that was only for a couple minutes. dont know if i should have disconnected it longer or if it doesnt make a difference. I do plan on going to a dealer tomorrow and getting new o2 sensors maybe somehow i damaged them when installing them back in idk. but my guess is also something electrical

Disconnect you battery for longer/try to pull codes/clear codes/nothing you did should have disabled the engine. Check o2 connections.

Edit: leave battery disconnected for 30 min.

i will try that now and see what happens

wish i had a scan tool to be able to clear the codes tho. so i wont be able to do that

Where in NY are you? Are the battery terminals tight?

so i just tried to disconnect the battery for 30+ min and still nothing

im in rochester and yes they are tightened down

Try this.

http://www.ft86club.com/forums/showthread.php?p=3219936

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The car should run fine on stock tune


You dont need to reset ecu



If the car wont stay running you have left something unplugged, either electrical cable or hose or you have damaged a sensor or wiring.

i gave the method a try that they explained but didnt work. worth a try but thanks for the link

thats what im thinking. ,im gnna get new o2 sensors tomorrow and give that a try and hope it works

Hmmm that might be very expensive. You rearly need to test them first they may be ok.


Did you touch intake at all or any intake hoses .


The car should run with 02 sensors disconnected, will go into limp mode but should run.


You symptoms could be a big intake leak or intake hose disconnected

it does run without the o2 sensors connected. but i will check the intake area and see if anything is disconnected somehow

so idk if this matters but i tried to see if the car would run with only one o2 sensor and it does. its the one closest to the overpipe (one with black connector). might mean the other o2 sensor is bad. idk

its able to idle perfectly and go down to normal rpms at around 700 when it gets warmed up. but when i try to give it throttle it starts to die but stays on when i let go of throttle

Click link


Go to engine hybrid system


Engine control


Then air fuel ratioo sensor ie front sensor
And heater o2 sensor ie rear sensor


Test as per instructions


These sensors are like $200 each


Test before replacing



https://demos.starbase7.net/t3Portal..._rm_index.html

I think you've damage the o2 sensor while changing the exhaust, they can be very sensitive, with a slight knock they can be faulty. but still doesn't explain why the car shuts off right away since you can run fine with only one.
long shot but are all the grounds connected? have you accidentally swapped any plugs, or accidentally have the o2 sensors cables swapped around ?

so now after the car was running perfectly fine for a couple min with only 1 o2 sensor, it died on its own and now its only cranking

ill give it a shot

i did think that i accidentally swapped the o2 sensors as well so when i tried to switch them, one of the sensors wasnt even long enough to connect to the harness so my guess is i have them installed the right way

i dont have the tester but will get one tomorrow and see if they are actually bad

Could be another long shot, but have you tried putting the oem headers and fp back on and then turning the car back on ? when i swapped out my exhaust i only did the cat back and ran like that for a week or two so the ecu can adjust properly, maybe having too much change all of a sudden could be upsetting the ecu ?? i know you can swap the entire thing out and should run perfect right away but something seems to be upsetting the ecu?

thats also a possibility and will try that out tomorrow and see. who knows

I wonder if this isn't the result of using the wrong kind of anti-seize. They say it destroys o2 sensors.

If this is really a thing, I wonder how much it takes. Just spitballing here.

ive never heard of that but i did use the anti sieze that came from tomei with my headers

That totally negates my concern. I think that particularly the copper stuff does something weird when it heats up and vaporizes.