knocking, but pulls hard?

[GsxEcutioner]

hey guys. I have had this problem before but i still dont know. I have changed all my Throttle body seals and biss oring, and gaskets, I have also changed BOV and BOV gasket. Mods are
HKS BOV
EVO VIII FMIC and Pipe kit
MHI Big 16g
DSM GT High Flow Manifold
HKS EVC IV
2g Hard Intake pipe
2g MAF
Evo VIII Injectors
Evo IX Fuel Pump
Fuel Lab FPR
MLS HG
solid Timing belt tensioner.
ARP Head Studs
BSE
2g o2 housing
2.5-3' straight pipe.
KeyDiver chip
SAFC.
Pocketlogger.

I have been getting plenty of knock on the knock gauge. but it still pulls real hard. I always thought I was running rich, and I have changed the plugs twice already. and wires. Yesterday I notice that my boost gauge will spike at 20-25 psi and then drop down all the way to 10 ish when knock hits. is this normal? I have no idea whats going on. I cannot figure out how to move my logs to the computer and upload them here. My Idle still fluctuates so i am thinking my isc is bad. vacuum at idle is 12-14 in HG still, and Timing is on point. Thanks
-Shane

 

[cookmeup272]

So initially your boosting 20-25psi and then it drops to 10? And its knocking at the same point? You checked for boost leaks already or no? Replacing that ISC should definitely fix the idle.

 

[95blackGsTurbo]

Sounds like the idle and knock are intertwined. I would definitely do a good boost leak test because it shouldn't taper that far. And with stock cams, you should be ~20 in/Hg. If I have to take a random guess, I would point to that BLE tensioner. I have heard nothing but bad things about them. They don't auto tension and when the belts starts to stretch, it can jump teeth easily. Another thing that is really missing is a wideband. 20-25psi on pump is pretty risky with no A/F numbers, even with a logger. Knock will pull timing. Pulled timing equals less boost. Try doing some 15-16psi pulls and see if it holds steady.

 

[juanpac0]

So you're basically not controlling your boost and wonder why you're knocking? for that one.

Also, "pulls hard" is relative, your car doesn't "pull hard" if it's knocking a ton, that's just the way the ECU works. Have you checked your timing at the CAS? Try retarding it a bit at the CAS if you're still on the 1g timing map with the chip.

My guess is that since you're on an AFC your fuel adjustments are messing up your timing causing knock, although it may "pull hard" due to prematurely advanced timing until your timing curve sees the limits of 91 octane.

Also, do a proper boost leak test.

 

[GsxEcutioner]

Thanks guys, Yuri come on over, lets do the boost leak test again.

 

[rstchris]

After a good leak test you should pull some timing til you can at least borrow a WB and get the fuel dialed in. Then feed it boost, then timing.

 

[GsxEcutioner]

yea but still doesnt explain the idle 14hg at idle...

 

[juanpac0]

A boost leak does.

 

[GsxEcutioner]

wanna let me borrow the tester again?

 

[Killa_dsm]

wanna let me borrow the tester again?

Go make one its really easy. IC Pipe Tester

 

[rstchris]

With high elevation and very little timing you can see low vac. at idle too. Just triple check for leaks then pull some timing from up top and take it from there. I always open the BISS, clamp a plastic bag and a rag over the comp. inlet and shove air into a vac line.