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If the KS circuit needs to see some knock to avoid throwing a code, maybe more static advance would give you the knock it wants to see with that 93 octane?
How would I go about doing that? custom tune? I’ll still pretty new the corvette/Chevy small
block world.
Are you saying that you have never checked or adjusted the ignition timing on your engine?
Unfortunately I have not checked the timing. I just ordered a timing light. Should be here next week. Do you think if my timing is off. For example somewhere ATDC instead of BTDC. This would be causing some of my issues? Specifically knock issues?
Alright unfortunately the SES code 43 is back. I’ve back probed the ecm b7 wire and it is getting 9v at all times. Except at startup it gets about 7-7.8 then right back to 9v at idle. Therefore my conclusion is that the ECM is NOT seeing any knocks when it enters closed loop and throws the code and retards timing.
My snap on scanner sees 2-3 knocks at start up but does not see any when the “function test” is performed at 195 degrees coolant temperature. Ecm not seeing any knocks at WOT. It’s my understanding it needs to see some at WOT to avoid the code.
Whats going on with this? I’m so tired of dealing with the code. The car is unable to be driven like this. Runs great until closed loop then throws code 43 and runs like crap.
Alright more info to add... I disconnected knock sensor and tied connection up. No SES at start up and only triggers at WOT above 195* coolant temp or closed loop operation. Therefore I’m back to the knock sensor not detecting any knock.. I guess I’ll replace the knock sensor again and see if it cures the problem. Maybe I got a bad knock sensor out of the box..
So if somehow my timing got retarded on its own it won’t knock at all? How would my timing get so retarded for this to happen?
This must be my issue... knock sensor is working bc RPMs drop when I tap on block. Voltage is exactly 9 volts from esc to ecm meaning the knock sensor is not recording any knocks at WOT/closed loop function test.
Hoping to to get my timing light soon and get this taken care of. I’ll report back with my findings.
p.s.: You won't see any knock if the ignition timing is retarded.
Hot Rod, are you able to confirm that if somehow my distributor was turned enough and in fact retarded the timing the engine will not knock? Haven’t received my timing light yet. Ordered online and I’m in Florida battling a hurricane right now. Below picture is exactly what I am experiencing. I am FAILING the performance test where the ecm looks for spark knock. How would my engine timing get so retarded? Can this happen on its own? What other reasons would cause a NO knock situation? A reminder, I am able to drop RPMs when I tap on the block. So the circuit/sensor are working.
timing was waaay retarded. Not sure how I didn’t catch this. It’s my first gas engine (I’m coming from a diesel background)
I wanted to update the thread..
timing is set, new rapid fire plugs, wires, dist cap, rotor, coil, and icm. TPS set properly. She RIPS now.. can burn the rears with ease.
The silver lining in all this I guess is, I researched SO much chasing this code that I learned A LOT about HEI, EFI, EST, ESC, knock sensors, pinging, octane, SBCs and corvettes in general. I look forward to continue using this forum!! Thanks to all!!!
Not idiotic - just a learning experience. Glad you got it sorted out, and it's really appreciated that you came back and posted the solution. All too often, we never find out the end of the story.
timing was waaay retarded. Not sure how I didn’t catch this. It’s my first gas engine (I’m coming from a diesel background)
I wanted to update the thread..
timing is set, new rapid fire plugs, wires, dist cap, rotor, coil, and icm. TPS set properly. She RIPS now.. can burn the rears with ease.
The silver lining in all this I guess is, I researched SO much chasing this code that I learned A LOT about HEI, EFI, EST, ESC, knock sensors, pinging, octane, SBCs and corvettes in general. I look forward to continue using this forum!! Thanks to all!!!
Glad you found it!!!
I wouldn't have thought to go after timing either, if that's any consolation, and I also learned a ton from this thread so your difficulty helped other folks too!
