sputter, hesitate under WOT and rough idle

Tyler Hill

Tyler Hill

Greenie N00B Member
I’ve had this 08 speed3 for about 6 years has 68k miles on it

I ran into a problem what about 4 years ago the car would sputter, hesitate under WOT, then it started to rough Idle (sounded like it has a massive cam) my stft pegs at 25. No vacuum leaks just replaced the 02 and maf sensor
Please I need some help!!!
 
Need some info to help,

What's your ltft at idle and while crushing?

How old are you plugs? Which one are you running and what gap?

Gave you ever cleaned your intake valves, flow tested injectors and replaced seals?

What mods/ tune?
 
Thanks for responding

NGK 1 step colder plugs. .026 gab
Just replaced a few days ago

•cs injector seals
•cs fmic
•cs hpfp
•cs 1st gen turbo
•cs intake with tip
•cs boost controller
•cs tbe (catless)

Tuned on e30 mix by Justin

Under normal driving conditions it sits at 25
Wot it drops to 0

I’ve cleaned the hpfp

Have not got the injectors serviced or anything along them lines

I do have some crank case pressure

I put the top mount and the stock bpv I have no boost leak or vacuum leaks.

That’s +25 too btw

Can I haven’t drive it enough to get a good ltft just around the block a few time


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Logs.

Edit:
Awa this should be a requirement for tshooting threads; if there's a way that the requestor can pull logs, they should have some available when posting, IMO.
 
I have a log of it idling I will be able to post here soon

Sorry I’m pretty new to all this!
Bare with me


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Trims are pegged out both long and short, and idle G/S seems pretty low to me at 5.

Question:
1. What size intake is it?
2. What changed just prior to having this issue?

Suggestions:
1. Take a picture of the intake (of the engine bay really, but make sure the intake is clearly visible) as it sits right now and post that to thread
2. Pull the filter off the intake, inspect the inside to make sure the airflow straightener isn't fucked up or broken or something is stuck on it (not sure how that would happen)
 
Okay I’ll grab a picture tomorrow I’m at work at the moment.

I believe it’s the 3in intake

And nothing changed it slowly started to get worse overtime, it was hardly drivable. It would buck and kick real hard and had a hard time reving out the rpms.


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I inspected the intake yesterday and it all checked out

My fuel mileage is HORRIBLE also.


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I did notice your AFR was abnormally even; one cell deviates in the first log.

While you're in there, maybe pull the intake and disconnect the secondary O2 sensor to see if that changes anything. Else, might need a new primary.
 
Okay I can try it. will the secondary o2 cause that kind of problems? I did just replace the upstream and the maf (oem ones)

Sometimes it will randomly reset itself and the stft will go to +1 then slowly climb back to +25


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Secondary O2 is used to calibrate the primary. I've not had a secondary in my own car in a very long time.
There's also the possibility that the primary you bought could be a turd too.
 
Okay I will try that in the morning see if it changes anything. I will keep In touch

Thank you!


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I'm gonna go out on a limb and suggest that your primary O2 isn't working well or it's a narrowband, based on what is visible in log 3.

Replace that shit with OEM immediately.

Also, name and shame the mfg/source of whichever one you bought and are using now.
 
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