Need some help here. Had a basic Gen III top swap on my '02 last year and over the winter I added a stage 2 intercooler, 65lb injectors (got these over 42lbs because I have a cam going in next year) Gen V w/3.4 pulley, zzp billet fuel rails, northstar, 85mm maf, and aluminum valve covers. Got an Overkill mail order tune specific to my mods.

My problem is when I get to about 30% throttle I get 3-6* of KR. This is at 15* of timing advance. I figure the 3.4 pulley is pretty conservative for my mods and I'm also not seeing more than 1lb of boost on my gauge so I don't really know if its boost related. I pulled the supercharger belt off and the KR remained.

I've eliminated the swaybar as a source of false knock, but I am wondering about the aluminum valve covers??

Any ideas? Do you think its tune related?

Other mods are...1.9 rockers, headers, 3" catted dp, 160* drilled tstat, 103 plugs at .045

 

Sounds like a vacuum leak or something wrong with your BBV. with a 3.4 you should at least see 8-10 lbs of boost. I think because of the MAF curve you're too rich when you get on it because the boost isn't going too. Only other thing I can think of is belt slip or incorrectly routed belt.

 

Belts are routed correctly and no visible signs of slip.

Is there anyway to test the BBV? Its not hooked up to the solenoid, just working off manifold vacuum.

I get 15 in hg of vacuum when the car is first stared then it goes to 18-20 in hg once warm on my boost/vacuum gauge. Vac lines run from LIM to FPR to MAP to Boost gauge.

 

I just looked at a vac line diagram and the FPR is off the T on the top of the S/C not from the LIM.....Looks like I hooked that up wrong

 

Yeah that's supposed to come from the T line underneath the blower snout. I bet that is causing some pretty ugly fueling issues up top. The top of the blower should connect to the brake booster, the HVAC, and the BBV. Still don't know how you're not getting boost though.

 

You seem to be modded enough that you should have a real tune.

A mail order one just might not be working for you. Some engines are difficult.