Tried everything I can think of- can't stop knock retard - looking for ideas - Third Generation F-Body Message Boards

torqueaddict · 10-20-2008, 09:07 PM

Hi - I have an 89 GTA 5.7 TPI. I installed vortec heads, sd vortec intake, edelbrock headers. ZZ4 cam. All smog stuff intact.

When I went to start tuning I couldn't stop getting knock retard. I am back to the stock prom (ajup). Base timing is 8 degrees. I kept adding to the base timing in the prom until I took out whole 14 degrees of advance - I still get knock. I started adding fuel and doing runs. I have a wideband and I am running close to 11:1 at WOT. Still knocking. I ran a dedicated wire from the knock sensor to the esc module and a dedicated ground to the module. Same results. Also replaced the knock sensor. No difference.

Here's a log if anyone can check it out and give me pointers:
http://members.bellatlantic.net/dantill/rewire.csv

thanks in advance for any tips - I've been at this a long time and I am very eager to figure this one out!

18436572 · 10-20-2008, 10:39 PM

Maybe verify the timing with an advance timing light.

JP86SS · 10-20-2008, 11:47 PM

You can't log using the $32 DM if you have a 730 running $8D.
Try logging with the $8D version or otherwise change to a MAF memcal/bin.
AUJP is $8D (SD, not MAF)
I'm confused, what is your setup

torqueaddict · 10-21-2008, 07:00 AM

I am running MAF - I will double check tonight but I am sure I'm running the right memcal - I just got the names mixed up in the message. I have the "165" type computer. I was running with arap before but I switched back to stock and dialed back when I was getting knock.

torqueaddict · 10-21-2008, 07:05 AM

Other thoughts - I hear no pinging/knock, and the car runs great with arap other than the knock. With all the timing removed not very responsive (base timing in PROM at about 22 deg), so I know that's working. I did have the cam, heads and intake off, and I am an amateur, so maybe I did something to throw off where the timing mark is?

Jaysz28 · 10-21-2008, 07:58 AM

When you check the base timing, you are disconnecting the EST wire correct?

-jason

Six_Shooter · 10-21-2008, 08:08 AM

You're sure there's no mechanical issues? No loose rockers or worn bearings? I've even heard of worn valve guides causing a sound that the KS might pick up as knock.

torqueaddict · 10-21-2008, 08:31 AM

Quote:

Originally Posted by Six_Shooter

You're sure there's no mechanical issues? No loose rockers or worn bearings? I've even heard of worn valve guides causing a sound that the KS might pick up and knock.

I will consider that as a possiblity.

Engine has 55k original miles, L98. Heads are new Vortec. Burns no oil or anything. Knocking starts when I floor it.

I remember following a procedure in the manual for torquing the rockers, they seemed pretty tight.

torqueaddict · 10-21-2008, 10:57 AM

I just read an EGR issue can cause knock.

Can I just diable EGR in the PROM to rule it out as a cause of knock? Also, I have no codes, either.

torqueaddict · 08-12-2009, 07:01 PM

just looking at my old messages - dropping 1 heat range fixed it (R44 to R43 AC plugs)

1MeanZ · 08-23-2009, 09:32 PM

if it runs well and only knocks when you floor it, try taking some timing out of the PE table...

LoudmouthSS · 08-28-2009, 04:56 PM

If you pulled timing the knock was still there i would say its false. Disable the knock sensor or desensitize it a bit and be done with it.

Drumer919 · 08-29-2009, 01:55 AM

Quote:

Originally Posted by LoudmouthSS

desensitize it a bit and be done with it.

How do you do that?