Is you Knock sensor taking performance down for the count?

[LGAFF]

never saw one on the 92 when it was off..

[VetteMed]

Originally Posted by gbmidyear66

I'm confused... I had understood (incorrectly?) that the LT5 does a self test of the knock sensor / circuitry at start up. If the seonsor is inoperative - presumably it will indicate a DTC?

Yes, this should trigger a code 43.

[scottfab]

Originally Posted by gbmidyear66

I'm confused... I had understood (incorrectly?) that the LT5 does a self test of the knock sensor / circuitry at start up. If the seonsor is inoperative - presumably it will indicate a DTC?

This is almost true but not quite. Yes the ECM will do a test of the ESC module once after start but these two conditions must also be present:
1. Eng temp above 194deg F.
2. at or near WOT (high load)

So, based on this circuit description it is entirely possible to not get a code 43 when the sensor is unplugged.

[gbmidyear66]

Originally Posted by scottfab

This is almost true but not quite. Yes the ECM will do a test of the ESC module once after start but these two conditions must also be present:
1. Eng temp above 194deg F.
2. at or near WOT (high load)

So, based on this circuit description it is entirely possible to not get a code 43 when the sensor is unplugged.

Thanks for clarifying the fine print Scott

So..... if you drive like a granny (I can assume LGAFF does not qualify on this count), OR you've changed your thermostat and/or fan cut-in - you won't get a DTC?

I dunno - I have early activation of my fans and I still see temps > 200. Sounds like I need to disconnect the sensor and see what happens.

[scottfab]

Originally Posted by gbmidyear66

Thanks for clarifying the fine print Scott

So..... if you drive like a granny (I can assume LGAFF does not qualify on this count), OR you've changed your thermostat and/or fan cut-in - you won't get a DTC?

I dunno - I have early activation of my fans and I still see temps > 200. Sounds like I need to disconnect the sensor and see what happens.

I also have early "fan on" but don't see temps north of 200 on short drives so in my case I'd not see a 43 (if sensor or ESC were defective) on every drive.
I can tell you that yesterday I hit WOT at above 200 several times on the way back from Home Depot because I chose to go to the one that is a few miles farther away than the one nearest me. I did this ostensibly to test to see if I'd get a 43 but also as an excuse to feel the WOT and to save some $ by shopping in a "no sales tax" US state

[Vettetech1]

Bring up this thread again. Got a 92 zr1 here has a code 43. Suspecting a knock sensor issue. OHMed the sensor and it is at 3.891k. Customers car not sure of full repair history on it. Know all primary and Secondary injectors have been replaced over the past 3 years, and the fuel regulator was replaced last year. Just don't seem to have the power it should. Any suggestions would be helpful as i don't see to many of these.

[LGAFF]

Is your ASR light or other lights coming on? I had a crack in the board of my chip for the knock sensor

[Pete]

Did you or somebody replace knock sensor?
You might have a 1990 knock sensor.

I will check and get back to you later.

Pete

[XfireZ51]

Have a read on this thread for some additional explanation. It's not a matter of knock, it's a matter of the knock sensor circuitry being operational. You don't get a MALF code if knock is occurring.

http://www.thirdgen.org/techboard/di...de-43-esc.html

[Vettetech1]

Originally Posted by LGAFF

Is your ASR light or other lights coming on? I had a crack in the board of my chip for the knock sensor

I did see the service ASR light come on yesterday, but it isnt on now. The service ride control light will go on and off while driving but it did that last year also. This all started as a feeling of a miss in power mode when you get on it. I checked the injectors and had 2 secondary injectors at 8 ohms the rest were 12.6. I replaced the 2 bad ones and suggested we replace the other 2 secondaries that were OE. So over the past 3 years all 16 injectors have been replaced. The car was running like it should fast and strong, it then sat for 2 weeks till the owner came, when he picked up the car he said it was running rough and thought maybe it just needed to be driven. Now it acts like its missing on hard accel in both power and non power modes. Like injectors are messed up again. I put my solus pro on it and found a 43. hit up google and found you guys. cleared the code and havent seen it back on yet but haven drove it either. Can feel the miss or stumble just goosing it in the bay.