I thought my problem was with the increased timing advance from the Performance Resource chip -not so. I put the stock chip back in and the knock was slightly worse. The PR chip has the cooling fan on all of the time with the temp down to 196'. With the stock chip the temp was up to 220'+. I checked for loose brackets or anything else that would bang up against the engine at speed and found nothing.
The tank was almost empty of the 91 octane gas in it, so I went ahead and filled up with 93 to see if there would be any difference -there was none. I had put some combustion chamber cleaner in the tank last week.
I noticed that as the revs increased the amount of advance it was taking out decreased from 12' down to 4' or 5' just before shifting. I will soon be checking the fuel pressure to make sure its not going lean but, that wouldnt make sense with the knock decreasing at the upper end -would it?
Is there anything that would show up on the Tech 1 that I could look for that would help me figure out why this thing is still knocking?
The SES light is not on & there are no stored codes.

------------------
89 IROC-Z 5.7L 2.77 GEARS
130,000 MILES
ALL FREE MODS
K&Ns FILTERS
FLOWMASTER MUFFLER
PERFORMANCE RESOURCE CHIP
AFPR & PORTED PLENUM
Best 1/4 E.T. 14.09 @ 97.2 MPH
Best 1/8 E.T. 9.09 @ 77.4 MPH
Best 60ft. 2.03

 

How do you check the EGR Valve for correct operation. I remember something about bad EGRs or for that matter, removed EGRs(blocked off)that decrease the spark knock tolerance. Does anyone have more info on this subject? -Thanks for the help guys

 

whiteroc,
there are several paths to go on this.
first off, 12deg retard sounds like something
is upsetting the knock sensor. some exhaust
systems can effect the ks. since no codes are
found, id ohm the ks from the center pin to
ground. 3500-3900ohm resistance. any more or
less replace it. second check to see if you
have 2.5-4volt at ks key on engine off.
standard retard in a MAF system is 4deg to
2500, 6deg to 4000, and 12 4000+. a lean condition
could cause this your block learn would be
about 150-170 and fuel integrator is 140-160
to cause that. your O2 volt should be dirt
low .01-.4 volt. what do you have your
inital timing set at? your temp is at idle or
cruise? if your fans are set to run all the time
and your cruise temp is high, inspect the
rock guard is still attached. if so, your
t-stat is? 160? 180? 195? check there is no
trash between the condenser and radiator.
fuel pressure between 38-45# is norm. cats?
possible restriction. EGR operation might be
nixed in PR chip observe the TECH1 EGR signal
on both chips. still the EGR will only help
if the ping is nominal. not knocking your gear
ratio but thats a hell of a load for a medium
weight car.
hope this helps!
airdeano

 

[This message has been edited by whiteroc (edited September 27, 2001).]

 

I know this is TOTALLY out of left field, but if you still can't find the problem, check the bellhousing-to-engine bolts. I know a guy that was like missing 3 and on the verge of tearing his engine apart to find a "rod knock". I actually have never heard spark knock, so I don't know if it is any different, but if it isn't and you can't find the problem, why not check??? Cant hurt! Good Luck!

 

whiteroc,
id do this:
MAF(g/ps) TPS 02 Block Learn Fuel Integrator
Idle/Park
Idle/Drive
2000 RPM
3000 RPM
4000 RPM
your TECH1 will display the readings. to
achive the higher rpm, you can use second gear.
this may take two people one driver the other
looking and writing.
the b/l and f/i will determine the fuel.
do you remember the condition of the distributor
gear? worn? knife edged? ok?
the ign rotor isnt burned severly?
some other troubleshooting ideas..
airdeano