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CEL: O2 Sensor. Knocking/Boofing

Old 10-18-2018, 09:51 PM
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Join Date: Oct 2018
Posts: 2
Question CEL: O2 Sensor. Knocking/Boofing

So hard to explain but here goes.

What I have: JLT CAI 3, BBK 62mm Throttle Body. Ford High Performance Intake Manifold. BBK Long Tube Headers, BBK Off Road Xpipe, Flow Master Outlaw Mufflers, recently HAD to install exedy stage 2 clutch (old one disintegrated)
I have Tuned and Datalogged and ReTuned with their attempt from BAMA (I get free tunes for life from AM/BAMA).

About a year ago I ended up putting the Ford HP Intake on after locating a crack in my Stock Manifold and O2 Sensor bank 2 sensor 1 response slow started coming on. and was hearing an inconsistent "boof" noise really deep and seemingly coming from front of vehicle. no specific pattern and sometimes random and at higher Gears with RPM Dont hear it at all. for an idea its like "Boof, Boof, Booboobobooof boboof" I've unplugged 1 at a time injectors 1 at a time spark and never seemed to change at all. the boofs went away for quite a while after replacing spark plugs. The CEL never came on until my first issue with the Intake manifold but came on like extremely rarely sometimes 500+ miles once in a blue moon on startup. now it could be instant or it could happen within 5 miles or sometimes go a whole day or 3 of driving without issue...

reason its such a huge problem now is the "boofs" are back. O2 Sensor Bank 2 Sensor 1 Slow Response is back/P0153, and "stuck lean" P2197 come on. whether I am idling or driving it could randomly go into a shuttering feeling super heavy back firing (which isnt the "boof sound" like its having a choking issue or something gas mileage went from 280 down to 200 I've replaced the sensors with bosch read a bunch of crap on those switched to the stock/oe style on both banks 1 and 2 sensor 1. Yes I have a tune that "deleted the B1/B2 sensors 2"
I replaced the seals again under my HP Intake retorqued PVC valve is nice and secure and open. when watching my data i can see Bank 2's short term fuel doing things a bit slower in response compared to Bank 1 Short term changing every half second when it seems to do the rough Run/Idle and back firing its bouncing between %.70 and or %1.3 after a bit it goes back to normal but whats always there is the "boof" I feel like my car is gonna stop running on me while driving. I've taken a Mechanic stethoscope and listed to each part of the valve cover, each injector, each coil pack and nothing sounds out of ordinary.. I even switched O2 Sensor sides and switched connection cables of sensor 1 and 2 on each side made no difference. returned to stock and reloaded tunes again. switched sides of coil packs the only thing I havent done is switched sides of injectors. blew smoke to check for vacuum leaks no issues, sprayed carb cleaner brake clean and all kinds of crap to see if engine would run differently... sea foamed gas tank, sea foamed through Brake Booster Vacuum I run a 91 OCTANE tune Royal purple 5w20, royal purple in tranny and royal purple in diff. I dont know what to investigate next.. outside of maybe swapping injectors sides to see if one actually is failing..

Any help or ideas is appreciated
Thank You.
Archomni is offline  
Old 10-19-2018, 02:07 AM
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That is not what Boofing is, according to Brett Kavanaugh...
08'MustangDude is offline  
Old 10-19-2018, 03:49 PM
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What's the fuel trim look like on the the faulty side? LongTerm should be close together but the ShortTerm on the wonky side should be bouncing everywhere at idle. Look at the plugs on that side to see if an injector is failing. It will be wet if you wait for the engine to get cold then just do a quick start up and shut down. Do you have a different Intake to swap in even temporarily? Yes you did a smoke check etc but the intakes are massive and plastic on these so you may have missed something.
Derf00 is offline  
Old 10-19-2018, 04:30 PM
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Join Date: Oct 2018
Posts: 2

.7 and 1.3 on bank 2. .9 and 1.1 on bank 1 bank 1's changing constantly and fast I can literally see the delay in bank 2 as it does all this its random when it goes into this delay field but it does return to a normal idle/driving and at some point will do it again but I am ALWAYS hearing the "boof" just a really deep sounding explosion i guess...
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