I'm running a lq9 with all the bolt ons and I just finished up my top end swap. I did 243 heads (stock height ) nnbs intake with edelbrock 90 mm tb, 218/222 cam 114 .600 lift, ls6 valley pan and 44lbs marine 8.1 injectors. It idles pretty bad and at half to WOT is bogs and spudders like crazy. Then I threw codes saying both O2 banks too rich. I check my fuel pressure and I'm getting 50-60 psi and holds the pressure at different throttles. My pulse width at idle is 2.4 -2.6 for the injectors. I check the o2 s and they are cycling fine and check maf and that's fine . My TPS reads 2% at idle so that's working. Any help would Greatly help !!! Please chime in with thoughts?????

Update::2/20/13
Problem solved the tuner had alot on his plate right now and they forgot to scale the new injectors. . **** happens we're all human. But I give him credit for admitting mistake and doing the right thing!!!:-)

 

So did you add the injectors while you did this swap? If so it needs to be retuned for the injectors

 

Injectors were added at swap but I had it retuned for the new setup

 

Not well enough, it sounds like.

 

I'm hoping that's it I checked everything else . Nelson's tune are normally spot on so I would be surprised if it was off

 

If the o2 s are working , I'm getting 50-60 psi at the rail , and no other codes than running rich , what else could it be other than the tune ? Also I changed over to the ls6 style valley pan and the port on the pass. Side valve cove got capped and I fed the valley pan port to the throttle body, as well as the port off the drivers side went to the top of the nnbs intake. Does that sound right for Pcv routing????

 

Any body????

 

Why would the 02's mysteriously start to work wrong after the swap. Have the tune checked over for the injector issue.

 

I meant that I just checked the voltage to make sure they were ok which they are. I think it has to be the injector programming because everything else seems ok. Has anyone ever needed a couple of back and forth tunes to get injectors dialed in???
And thanks mangle03gmc for your feedback:-)

 

I would check with NP to make sure they tuned for all the changes. You may have missed telling them one part. Also check and make sure all your sensor connections are good as well as spark plugs being seated well, and coil packs connected correctly. I also wonder if you have a vacuum leak.