Ill try some octane booster too maybe that will help. 
Knock sensor codes will NOT go away... possibility of fried comp?
Thread Starter
Joined: Jun 2007
Posts: 383
Likes: 12
From: Central Texas
Knock sensor codes will NOT go away... possibility of fried comp? Ok long story short, i put a 5.3 in my firebird which was a V6. All was well until i needed to change the clutch. ( 1 month or so later ) I pulled the trans, put the new clutch in myself ect. Well in the process of putting the bellhousing back on, I didnt notice i pinched the wires for the knock sensor ( pigtail side ) inbetween the block and the bellhousing.
Fast forward a week or so, car starts running odd. Knock sensor codes ( check engine light starts flashing da fuq? ) Low voltage both sensors... Doesn't make sense they don't get voltage, they make their own. (Ohms and AC )
So i pull the intake replace both of the sensors and pigtail wire ( this is where i found out i pinched the wires in-between the motor/bell-housing ) so i unplug it and rip the wires out and they were def toast. When i pulled the old sensors out they were def rusted/corroded ect.
So new sensors/wiring to harness connector and i start the car drive it a couple miles and its back to throwing the same codes. ( car idles at around 580-600 rpms and is sluggish ) So i pull intake check everything and all is well second time around. I unplug my pigtail to check if knock sensors are working and all checks out good. I ohm my wires back to pcm from the harness and they check out good nothing burned up there. All fuses check out good aswell.
The only thing i can think of is i possibly fried something in the computer but I have no idea how. So now im stuck with a car that constatly throws knock sensor codes, could the PCM possibly be fried?
Fast forward a week or so, car starts running odd. Knock sensor codes ( check engine light starts flashing da fuq? ) Low voltage both sensors... Doesn't make sense they don't get voltage, they make their own. (Ohms and AC )
So i pull the intake replace both of the sensors and pigtail wire ( this is where i found out i pinched the wires in-between the motor/bell-housing ) so i unplug it and rip the wires out and they were def toast. When i pulled the old sensors out they were def rusted/corroded ect.
So new sensors/wiring to harness connector and i start the car drive it a couple miles and its back to throwing the same codes. ( car idles at around 580-600 rpms and is sluggish ) So i pull intake check everything and all is well second time around. I unplug my pigtail to check if knock sensors are working and all checks out good. I ohm my wires back to pcm from the harness and they check out good nothing burned up there. All fuses check out good aswell.
The only thing i can think of is i possibly fried something in the computer but I have no idea how. So now im stuck with a car that constatly throws knock sensor codes, could the PCM possibly be fried?
Im pretty sure with a knock sensor code, the PCM retards the timing to prevent detonation as its running "blind" with no input from the knock sensors. What PCM and injectors are you running? I had this issue with my 5.3 running a 5.7 ls1 pcm before i had it tuned. it ran fine but i couldn't get the knock sensor codes to go away. New pigtail and sensors too. When i had it tuned the codes went away as the PCM was flashed for my injectors and engine size. If your running different injectors than the pcm is tuned for, you could be running lean causing the code. I hit 16.7 AFR before the tune, because the PCM i bought was tuned for ls6 injectors, while i was running stock ls1's.
Thread Starter
Joined: Jun 2007
Posts: 383
Likes: 12
From: Central Texas
Well I have a ls1 intake on it, the PCM is a 5.3 that came with the motor. I had a guy out of college station tune it for 5.3 motor/ls1 injectors/m6 trans.
Could i just tune the knock sensors completely out/lower sensitivity? I don't race the car, its just a daily driver.
Could i just tune the knock sensors completely out/lower sensitivity? I don't race the car, its just a daily driver.
Dont tune out the knock sensors, BAD idea. I don't know too much about tuning, Lol thats why i paid someone. Im sure someone will chime in that can help you out more. If all the wiring and sensors are alright, its most likely something with the tune. Have you tried running 93, just to see if anything changes? Thats the first thing i tried before i had my car tuned.
Thread Starter
Joined: Jun 2007
Posts: 383
Likes: 12
From: Central Texas
Little update.. It only seems to throw codes at idle. If I'm on the highway and reset the codes it doesn't come back, whenever I slow down and stop is when it will throw them. I also get a lean bank 2 aswell at idle, that's when the car goes to 580 or so RPM. I'm at a loss here, I have no idea why it's doing this.
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Thread Starter
Joined: Jun 2007
Posts: 383
Likes: 12
From: Central Texas
What codes did you get? I have aftermarket ones but they checked out ok. I plugged in the old ones outside of the motor and started the car and still get the same codes after a couple of seconds.
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Verdad Gallardo Thread Starter
Joined: Jun 2007
Posts: 383
Likes: 12
From: Central Texas
So i replaced intake gaskets/spark plugs/and new ac delco knock sensors and seems to be gone.. Just got a lean bank 2 code now, only at idle. Jeeeez fix one problem and get another lol. FML