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Hey guys. Two weeks later and I have not been able to find a used knock sensor. Have emailed everyone I could find through google. Have emailed specialists for vehicles that use the same sensor. Nothing. Nowhere.
So, my questions:
Can you run without the sensor? What issues can this cause in the 82 cross fire engine?
Is there a sensor that can be used instead? I understand that wiring change will probably be required.
Is there another option that doesn't include entire engine replacement?
Hey guys. Two weeks later and I have not been able to find a used knock sensor. Have emailed everyone I could find through google. Have emailed specialists for vehicles that use the same sensor. Nothing. Nowhere.
So, my questions:
Can you run without the sensor? What issues can this cause in the 82 cross fire engine?
Is there a sensor that can be used instead? I understand that wiring change will probably be required.
Is there another option that doesn't include entire engine replacement?
I think mine is still on my CFI Camaro....it is converted to carb....
I will look when I get a chance and see if it is still there....if it is, you can have it for a bottle of Crown
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
Originally Posted by Jebbysan
I think mine is still on my CFI Camaro....it is converted to carb....
I will look when I get a chance and see if it is still there....if it is, you can have it for a bottle of Crown
Well, sure as **** it is still there.
46,000 mile car.....I would assume that it is still good.....
If someone wants this, PM me....buy me a bottle of Crown and it is yours!
So I'm still looking for a 'cross'. Tom/ Buccy sent this to me.
this will tell you what we're up against.
Jebby...I 'crossed' the 82 LG4 Firebird and Camaro and got nada.The 82 sensor was a strange bird. Two wire connection, signal and a shielded ground.
Each particular knock sensor is tuned exact to match the ESC Knock sensor module.
The KILO-HERTZ RANGE IS UNIQUE TO EACH.
THE ESC IS A HIGH GAIN LINEAR OPERATIONAL AMPLIFIER THAT SENDS A 0-5 VDC SIGNAL BACK TO THE ECM.
The ESC puts ot a + 5Vdvc signal. Return path is engine block ground.
Knock signals are a AC Alternating Current waveform.
A shift type carrier signal riding back on a DC voltage reference .
What I have found in the past is each Knock sensor and ESC IS TUNED.
LIKE A U SHAPED TUNING FORK.
DETECT THE DESIRED KILLOHERTZ KNOCK SIGNAL AND THE ESC FURTHER ELECTRONIC FILTERS ELECTRICAL NOISE.
THERE IS A PRESET TIME DELAY ALSO FROM THE TIME ENGINE KNOCK DETECTED TO ACTUAL 5VDC SIGNAL SENT TO ECM.
CONFIRMED LAB OSCILLOSCOPE TESTING ON THE CAR AND DRIVING.
IF THE KNOCK SENSOR IS UNPLUGED AND CAR IS DRIVEN, THE COMPUTER STILL COMMANDS A SELF TEST OF THE KNOCK SENSOR 2-3 TIMES PER HOUR ENGINE ON AND CAR DRIVEN.
FULL IGNITION TIMING ALLOWED. CAN BE AS HIGH AS 50 DEGREES BTDC.
NO KNOCK DETECTED. ECM ASSUMES KNOCK SENSOR FAILURE.
IGNITION TIMING PULLED BACK 30-40 DEGREES.
NOW THE ENGINE HAS ABDC IGNITION TIMING.
VETTE RUNS LIKE CRAP.
SCALERS SET IN EACH CAR BIN FILE IS UNIQUE.
PRETTY MAX FOR VETTES FOR ULTIMATE STREET PERFORMANCE ON PUMP GAS.
YOUR VETTE WAS TUNED FOR 100 % PURE GASOLINE.
HARD TO FIND IN MOST AREAS OF USA.
PURE GASOLINE ONLY GUARANTEED IN 110-120 MOTOR OCTANE RACE FUEL OR 100 LL AV AIRPLANE PISTON ENGINE FUEL. UNKAHAL
So I'm still looking for a 'cross'. Tom/ Buccy sent this to me.
this will tell you what we're up against.
Jebby...I 'crossed' the 82 LG4 Firebird and Camaro and got nada.The 82 sensor was a strange bird. Two wire connection, signal and a shielded ground.
Each particular knock sensor is tuned exact to match the ESC Knock sensor module.
The KILO-HERTZ RANGE IS UNIQUE TO EACH.
THE ESC IS A HIGH GAIN LINEAR OPERATIONAL AMPLIFIER THAT SENDS A 0-5 VDC SIGNAL BACK TO THE ECM.
The ESC puts ot a + 5Vdvc signal. Return path is engine block ground.
Knock signals are a AC Alternating Current waveform.
A shift type carrier signal riding back on a DC voltage reference .
What I have found in the past is each Knock sensor and ESC IS TUNED.
LIKE A U SHAPED TUNING FORK.
DETECT THE DESIRED KILLOHERTZ KNOCK SIGNAL AND THE ESC FURTHER ELECTRONIC FILTERS ELECTRICAL NOISE.
THERE IS A PRESET TIME DELAY ALSO FROM THE TIME ENGINE KNOCK DETECTED TO ACTUAL 5VDC SIGNAL SENT TO ECM.
CONFIRMED LAB OSCILLOSCOPE TESTING ON THE CAR AND DRIVING.
IF THE KNOCK SENSOR IS UNPLUGED AND CAR IS DRIVEN, THE COMPUTER STILL COMMANDS A SELF TEST OF THE KNOCK SENSOR 2-3 TIMES PER HOUR ENGINE ON AND CAR DRIVEN.
FULL IGNITION TIMING ALLOWED. CAN BE AS HIGH AS 50 DEGREES BTDC.
NO KNOCK DETECTED. ECM ASSUMES KNOCK SENSOR FAILURE.
IGNITION TIMING PULLED BACK 30-40 DEGREES.
NOW THE ENGINE HAS ABDC IGNITION TIMING.
VETTE RUNS LIKE CRAP.
SCALERS SET IN EACH CAR BIN FILE IS UNIQUE.
PRETTY MAX FOR VETTES FOR ULTIMATE STREET PERFORMANCE ON PUMP GAS.
YOUR VETTE WAS TUNED FOR 100 % PURE GASOLINE.
HARD TO FIND IN MOST AREAS OF USA.
PURE GASOLINE ONLY GUARANTEED IN 110-120 MOTOR OCTANE RACE FUEL OR 100 LL AV AIRPLANE PISTON ENGINE FUEL. UNKAHAL
No....this was an 82’ CFI car that I converted years ago.....sensor is a match for 82’ Vette.....
Hi, I'll be happy to buy you 2 Bottles. if you still have the knock sensor! Please let me know. I can send funds via zelle, check, package with bottles... whatever it takes. No one on forum seems to answer what happens without it.
Thanks, LG
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
Originally Posted by Larry G
Hi, I'll be happy to buy you 2 Bottles. if you still have the knock sensor! Please let me know. I can send funds via zelle, check, package with bottles... whatever it takes. No one on forum seems to answer what happens without it.
Thanks, LG
Apparently you DID NOT read the explanation I wrote above to Hal on this when we were researching the knock sensor dilemma... IF THE KNOCK SENSOR IS UNPLUGGED AND CAR IS DRIVEN, THE COMPUTER STILL COMMANDS A SELF TEST OF THE KNOCK SENSOR 2-3 TIMES PER HOUR ENGINE ON AND CAR DRIVEN. FULL IGNITION TIMING ALLOWED. CAN BE AS HIGH AS 50 DEGREES BTDC. NO KNOCK DETECTED. ECM ASSUMES KNOCK SENSOR FAILURE. IGNITION TIMING PULLED BACK 30-40 DEGREES. NOW THE ENGINE HAS ATDC IGNITION TIMING. VETTE RUNS LIKE CRAP.
Apparently you DID NOT read the explanation I wrote above to Hal on this when we were researching the knock sensor dilemma... IF THE KNOCK SENSOR IS UNPLUGGED AND CAR IS DRIVEN, THE COMPUTER STILL COMMANDS A SELF TEST OF THE KNOCK SENSOR 2-3 TIMES PER HOUR ENGINE ON AND CAR DRIVEN. FULL IGNITION TIMING ALLOWED. CAN BE AS HIGH AS 50 DEGREES BTDC. NO KNOCK DETECTED. ECM ASSUMES KNOCK SENSOR FAILURE. IGNITION TIMING PULLED BACK 30-40 DEGREES. NOW THE ENGINE HAS ATDC IGNITION TIMING. VETTE RUNS LIKE CRAP.
My first try would be to measure the resistance of the knock sensor to ground…..
Put a resistor close to this inline to ground.
The ECM may call for it but if it sees the correct resistance then all is well…..
The knock sensor being only a “warning function” might be ok by tricking the ECM….just a thought.
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
Originally Posted by Jebbysan
My first try would be to measure the resistance of the knock sensor to ground…..
Put a resistor close to this inline to ground.
The ECM may call for it but if it sees the correct resistance then all is well…..
The knock sensor being only a “warning function” might be ok by tricking the ECM….just a thought.
Jebby
Well Jebby, I do not think that would work actually. The ECM is not looking for a resistance value coming from the ESC. The real trick would be to fool the ECM that all is well via the ESC and the 5v signal. I'm sure it can be done and may tale some redesigning, but I'm done even thinking about this subject for a while, I have other things going on that take priority at the moment. I was going to get with my EE friend and see what we can come up with, but again, that will be another time. I will let one of the newer CF WIZ kids come up with a permanent solution.
Hi, I'll be happy to buy you 2 Bottles. if you still have the knock sensor! Please let me know. I can send funds via zelle, check, package with bottles... whatever it takes. No one on forum seems to answer what happens without it.
Thanks, LG
I mentioned this in another thread. If you're in need of a knock sensor and willing to experiment, a knock sensor and ESC module from a later 350 TBI car or truck should work in theory with any GM ECM. All GM ESC's module's send 8 volts to the ECM's spark retard pin and drops to zero when a knock is detected. My 82 CFI car has a 92 TBI ECM with the 82 knock sensor/ESC and works without issues. Does it work vice versa? Don't know. Get the parts from a junkyard and give it a try. It's only 4 wire swap.
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Originally Posted by Jebbysan
My first try would be to measure the resistance of the knock sensor to ground…..
Put a resistor close to this inline to ground.
The ECM may call for it but if it sees the correct resistance then all is well…..
The knock sensor being only a “warning function” might be ok by tricking the ECM….just a thought.
Jebby
Buccaneer is correct. The early ECMs don't have the ability to read the resistor in the sensor. (The resistor in the early knock sensors is there to bleed off voltage from "rough" handling prior to installation on the engine.) Once the sensor was installed and connected up on the engine, the resistor was essentially dead weight/ballast, as the ESC circuit provides the input impedance.
You are on the right track regarding some of the later ECMs and knock sensors. The ECM looks at the knock sensor resistance to determine if the sensor is hooked up. (This method only senses that the sensor is hooked up, and not if the sensor is generating an actual electrical signal.) The later yet ECMs looked for AC signal activity on the sensor line to check for sensor connection and integrity.
Disclosure: My experience is primarily with the '84 to '96 ESC systems, but I enjoy a good technical discussion about the '82 system.
Thanks for help
Car seemed to be running OK with sensor disconnected. Half hour to 45 min. trips, 60-70mph. Idles smooth. The stud broke off sensor leaving a hole on top. I threaded the hole today with 1/4-20 bottom tap and installed a set screw a couple turns and attached connector. Solid but I'm not sure if it's working or not. Seems to be running the same (good).
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
There is another way to work around the issue for the CFI guys. Replace the stock ECM with an EBL ECM and turn OFF/IGNORE the knock sensor counts in the software. However, by doing this, you have NO protection if your motor is actually detonating except for you, the driver if you happen to hear it and do something before the damage is done. I turn mine OFF and if mine were to detonate, I'm sure I would hear it screaming down the track. The upside to the EBL is that you can tune the motor to ANY mods later down the road that you like to include Progressive N2O and a N2O percent duty cycle column in a dump of the log. This is for progressive N2O usage which is a recent new feature built into the 3.1 What's Up software.
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
Even though I said I didn't want to delve back into this subject...I did a little today and thought of yet another work around maybe, but have NOT tried it to see if this would be valid or not. If you remove the ground from the ESC module, the ECM should think that everything is OK and no knock is present. However, we are back to the original issue about timing control at that point. If you actually do have knock present, the ECM will play dumb and give you full timing and no timing retard, which will at some point cause damage. Somebody would have to play around with this idea to see if the ECM would be happy in this condition though. Just a thought after looking at the diagrams today for a non-related issue, but what the heck.
I just bought this 82 collectors edition and have numerous issues. Changed the Coil, Starter as it was having issues starting and the negative cable was getting hot. It no longer does that and it does start right away.
I found the knock sensor connector lying on the exhaust and burned the connector. Trying to look of a connector but could not find the on displayed here on this thread. So ordered one from corvette central will report back when I put it in. The car runs crappy without the sensor connected. Before I removed the sensor wire off the exhaust pipe I also tested the MAP sensor it does get 5v but on the signal wire the voltage increases from 0.73 mV to 232 mV Could this be due to may be the connector shorting out. I did not check the map sensor after taking the knock connector wire off the exhaust pipe will do that and report back. Still would like to see if some one has finally found a knock sensor in the market. It seems like a very hard part to find like many others for this Model. Buccanner you have recently responded to my thread on crank but no start. Appreciate all your guys help.
Last edited by Satkhalsa; Dec 13, 2023 at 12:30 AM.
The upside to the EBL is that you can tune the motor to ANY mods later down the road that you like to include Progressive N2O and a N2O percent duty cycle column in a dump of the log. This is for progressive N2O usage which is a recent new feature built into the 3.1 What's Up software. 
