Knock Retard

[Trucked-up]

Dynoed my truck this weekend while hooked up to EFI Live.

I have a 99 GMC with a 99 LS1 from a TA. Truck intake and truck computer. Stock internals.

Starting at approximately 70% throttle I am getting knock retard. It ends up pulling about 5 to 7 degrees of timing. Timing advance is only about 14 to 16 degrees.

We changed the timing advance using EFI Live and did another run. Same thing.

I have deleted torque management.

Question, do I use the knock sensor from the LS1 or the knock sensor from the truck. Does it really matter?

Any other suggestions?

Truck runs fine otherwise.

Thanks

[farmtruc]

Did you get to look at your ltrims and a/f ratio, usually kr is due to running lean?

The ones that i've done, i've used the truck and ls1 knock sensors, i'm not too sure if it makes a difference.

You didn't post your HP/TQ times, how did the dyno turn out?


allen

[gr8twhite]

What is knock retard? I've got a 3.0 pulley to replace the 3.40 thats on now.He said it will be ok because i run 93 octane, but I need to watch out for it.

[Trucked-up]

My LTFT were in the +6 range for both sensors.

The engine is rated at 305 hp at the fly wheel, I got 250 hp and 296 lb/ft of torque at the rear wheels.

Do you think I need to make sure that I deleted torque management correctly?

Thanks

[farmtruc]

Knock retard is that pinging noise you here when a car has cheap gas, bad timing or something like that, to make it simple, lol, the technical definition is this:

Detonation (also called "spark knock") is an erratic form of combustion that can cause head gasket failure as well as other engine damage. Detonation occurs when excessive heat and pressure in the combustion chamber cause the air/fuel mixture to autoignite. This produces multiple flame fronts within the combustion chamber instead of a single flame kernel. When these multiple flames collide, they do so with explosive force that produces a sudden rise in cylinder pressure accompanied by a sharp metallic pinging or knocking noise. The hammer-like shock waves created by detonation subject the head gasket, piston, rings, spark plug and rod bearings to severe overloading.

it's bad!!

ya, if you can't hear the pingin, you're ok for a while, but you should get it checked out, oh wait, you're coming down for tuning so we'll get it straightened out, hhehehe,

see ya soon,

allen

[farmtruc]

Ya, your ltrims are positive, so that could cause detonation, i richen up the injectors when i see that, it usually cures the pinging.

do you have edit, how did you delete TM?


allen