when i am data logging sitting in the garage with the clutch in or out, holding the rpms even at 4K im not getting any knock counts or knock retard, im getting 35 degrees advanced timing but if i sit there and hold the rpms at any load than snap the throttle or go more than 50 percent i get crazy knock counts and upto 20 degrees of retarding in timing,


in about a minute i could keep opening and closing the throttle and get 300 counts, i use only chevron 91 octane, and have stock timing/motor, plugs and wires and all tune up is all recent,

where do i start

 

Well.

First thing I would do is verify everything for leaks(exhaust) and rattles(headers /trans issues/ something loose)

Then u need to visit the prom board and start going to work :-)

they never made a 350 with a 6 spd from the factory so u have some tuning to do....

Generally, I dont care what it does in P or N when I whack the gas. It doesnt matter.

What matters is how it feels when your going thru the gears or letting the clutch out to get moving.

later
Jeremy

 

this would be true to a point i thought knock sensors were tuned to a certain frequency that human ears cant hear meaning pre ignition..

 

They cant hear pre ignition.

They hear actual detonation and/or engine noises if the correct frequency.

This can be masked by outside noises(lod/rattels/etc) and/or with excessive fueling combined with too much timing.

later
Jeremy

 

My car does the same thing when snapping the throttle. We have tried everything you can think of including increasing the throttle enrichment in the code. When I say everything that includes replace everything from the 165ECM to the knock sensor. Even shielding the wires. Also checking for external noises from every source imaginable including the dampner etc. Can't find a thing.

Mine pulls 16 degrees of timing out in a heartbeat. In the code we just increased the recovery rate. When at the track I use 100 octane gasoline and bypass the knock sensor with a 100K resistor. By the way if you increase the throttle a little slower it won't do it. Only when you mash it.

Will be switching to speed density later this year and I will be interested to see if the problem goes away. Also does it with the 100 octane gas. So I believe it is false knock but cannot find the source.

Good luck in your quest and hope your problem is easy to find.

 

well i found out some of the problem that my vss is not connected with out that the ecm disables the knock sensor.

but if i do it when i clear the computer codes and just start it up and drive it still does it so i dont know what to think.

 

A) false knock(outised source, rattle or the like)

B) timing curve(try yanking more faster)

C)Accel. Enrich needs work in the prom

D) AE work plus playing with PE enable TPS set points)


later
Jeremy