I installed an LS6 intake over the weekend. I also changed the valley cover to an LS6. Ran the car for about 5 minutes and it then threw a code after it seemed to relearn the computer. I drove straight to AutoZone and there tool says it is most likely in this order:

#1 - Knock sensor
#2 - Knock sensor wiring
#3 - Knock in the engine
#4 - Fuel pressure

Now the one knock sensor had a little bit of corrosion or white rust on it, but what are the chances it went bad right after i installed the intake. Could the new intake throw the A/F ratio so far off to throw this code?

what do you guys think?

 

This happened to me also, after i installed my LS6 intake. It took me 4 more times of tearing the intake on and off to find the problem but it is most likely the harness for the knock sensors.

I changed both my knock sensors out just to find that i got the same codes. Go to GM and buy a new knock sensor harness. If it is pinched just slightly, it will throw knock sensor codes and your computer will pull a lot of timing at WOT. Mine was only showing a little tiny spot of bare pinched wire - it took me half an hour to find it!

Good luck!

 

yeah, those harness' are notorious for being bad since they get pinched like above said. replace harness, and replace any knock sensors that have any corrosion on them period. the money your trying to save by leaving it on there is not worth the headache of tearin it apart again.

 

great thanks!!! how hard is it to change the harness at the other end? or maybe i need to not be so lazy and just look at it. I didn't feel any HP difference with the new intake is that because of these codes and it changing my timing?

 

You might also want to download the FAST instruction sheet (I know you installed an LS6). In the sheet, they show two clips that must be removed from the knock sensor wiring harness to keep from crushing the wires.

 

I did remove the clips

 

well, it could have alot to do with the HP diff. but if your stock cam, you might not be able to feel the difference cause it'll be subtle on stock cam. with the intake off, the harness juts unplug's from the sensors and there's a plug at the back of the eng.. so three connectors and its off. BUT you HAVE to have the intake mann. off to do it. same goes for the knock sensors. if you do replace knock sensors, make sure to torque them to spec. too tight or too loose and they wont work properly, and more codes.