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Spark Knock code 43, replaced many parts

Joined
Jul 4, 2007
Messages
19
Location
Viva Las Vegas
Corvette
1985 Silver & 1987 silver
I have been having trouble of severe spark knock on my 1985 vette. I initially replaced the CAP, ROTOR, WIRES, COIL, CAPACITOR & HARNESS IN DISTRIBUTOR,, NEW PLUGS, NEW KNOCK SENSOR, NEW PIGTAIL CONNECTOR ON SENSOR, THE SPARK CONTROL MODULE, IGNITION MODULE IN DISTRIBUTOR, ALTERNATOR, ALL VACUME LINES, EGR VALVE, EGR TEMP CENSOR, PLENUM AND GASKETS, BYPASSED THROTTLE BODY OF COOLANT HOSES, NEW 180 THERMOSTAT, NEW PCV VALVE, MOBILE 1 OIL AND MOBILE 1 FILTER AND i BELEIVE THATS ALL.:mad

The last 2 items I did were the knock sensor and pigtail connector and then lastly the spark control module. after knock sensor and connector replacement, the knocking got better but once I drove 15 miles and floored it heard the rattles and the light came on and code 43 again. So I stopped by dealer and replaced the Spark Control Module by heater blower motor on passenger side and it seemed to fix it. then today at 104 degrees outside and humid, only after driving 15 miles and getting off the highway the 2nd light I gunned it 60% throttle and very tiny rattling and the light came on, code 43 again. the knocking and pinging has gotten better during these last 2 replacements, but still having problem. I used dry gas when I bought it, have put 100 octance racing fuel in it last time, previous tank was premium 92 oct.

Could this be an ECM? I dont know if previous owner put a chip in it or if this could even be the cause. emmission test was perfect just about? I am real stumped here;shrug , and broke,:bash need several beers:beer to relax. I would appreciate any type of info, really dont know where to go, car has 76k on it, looks like well taken care of, cant figure this one out. Even thought maybe the distributor pick up coil or unit could be bad?

I can add that when problem was at its peak, before last 2 repairs mentioned, that once i gunned it and pinging came on and then the light, the next several accelerations with the check engine light on it would not be almost gone (the knocking) but light remained on. It also would never ever do this when I left home cold for first 4-5 miles. fixing these things has made problem slightly better and runs better now, when light goes on power seems to diminish and runs slower.

THANKS FOR ALL THE HELP, ANY INFO GREATLY APPRECIATED.
 

bossvette

Gone but not forgotten
Joined
May 19, 2003
Messages
3,233
Location
West Unity Ohio
Corvette
1968 1997
one thing I didn't see is what your base timing is set at; balancers have been known to shift quite often so check to see that your timing mark is at true TDC.
I use the ole finger over the spark plug hole routine.
 
Joined
Jul 4, 2007
Messages
19
Location
Viva Las Vegas
Corvette
1985 Silver & 1987 silver
I tested many times with timing light on #1 plug and est connector unpluged at 6 degrees BTDC. you are saying this could be off if balancer has shifted. what method is this with plug hole you say, would like a detailed explanation of procedure if you would, i appreciate it, you can always learn and I would be greatful. thanks
 
Joined
Jun 10, 2003
Messages
159
Location
Springfield, MO
Corvette
1996 LT1 automatic, Polo Green
I tested many times with timing light on #1 plug and est connector unpluged at 6 degrees BTDC. you are saying this could be off if balancer has shifted. what method is this with plug hole you say, would like a detailed explanation of procedure if you would, i appreciate it, you can always learn and I would be greatful. thanks
Here's how you find true TDC:
http://www.cncengines.com/finding_true_tdc.pdf
It's not a V8, but the theory is the same. You'll need a piston stop, and some timing tape for your damper.

You could just pull 4 degrees timing and see what happens.

Ken
 

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