how is you ebay knock sensor holding up?
08-25-2012, 05:50 AM
#41
I love Maxima.org.
I also realize I'm borderline flaming... Guess I should wait until I am more awake and have more self-control before I post things on the org..
08-25-2012, 04:42 PM
#42
Senior Member
Join Date: Jan 2006
Location: Silicon Valley
Posts: 655
Yes, should get a code but according to FSM MIL will not light.
Normally, KS send this kind of signal to the ECM.
When ECM doesn't see the signal, it thinks the KS circuit is open and broken, then is sets timing advance way back.
When knocking comes, ECM sees this kind of signal from KS.
ECM takes this kind of action when knocking comes.
Note: This is from our 2005 car but 4th gen ECM should take similar action.
If you by pass the KS, MIL may not light but performance will suffer because ECM will back off timing unnecessarily.
If you use a non-OEM KS, it could work fine but one of the two below can also happen:
1. KS is too sensitive
Then it sends false knock signal to ECM and ECM backs off timing too frequently, performance suffers.
2. KS is not sensitive enough
Then ECM set timing too advance and knocking happens without being detected. In most severe case, engine damage can occur. But you should be able to hear knocking.
Normally, KS send this kind of signal to the ECM.
When ECM doesn't see the signal, it thinks the KS circuit is open and broken, then is sets timing advance way back.
When knocking comes, ECM sees this kind of signal from KS.
ECM takes this kind of action when knocking comes.
Note: This is from our 2005 car but 4th gen ECM should take similar action.
If you by pass the KS, MIL may not light but performance will suffer because ECM will back off timing unnecessarily.
If you use a non-OEM KS, it could work fine but one of the two below can also happen:
1. KS is too sensitive
Then it sends false knock signal to ECM and ECM backs off timing too frequently, performance suffers.
2. KS is not sensitive enough
Then ECM set timing too advance and knocking happens without being detected. In most severe case, engine damage can occur. But you should be able to hear knocking.
Last edited by SVI30; 08-25-2012 at 04:44 PM.
08-25-2012, 06:12 PM
#43
Yes, should get a code but according to FSM MIL will not light.
Normally, KS send this kind of signal to the ECM.
When ECM doesn't see the signal, it thinks the KS circuit is open and broken, then is sets timing advance way back.
When knocking comes, ECM sees this kind of signal from KS.
ECM takes this kind of action when knocking comes.
Note: This is from our 2005 car but 4th gen ECM should take similar action.
If you by pass the KS, MIL may not light but performance will suffer because ECM will back off timing unnecessarily.
If you use a non-OEM KS, it could work fine but one of the two below can also happen:
1. KS is too sensitive
Then it sends false knock signal to ECM and ECM backs off timing too frequently, performance suffers.
2. KS is not sensitive enough
Then ECM set timing too advance and knocking happens without being detected. In most severe case, engine damage can occur. But you should be able to hear knocking.
Normally, KS send this kind of signal to the ECM.
When ECM doesn't see the signal, it thinks the KS circuit is open and broken, then is sets timing advance way back.
When knocking comes, ECM sees this kind of signal from KS.
ECM takes this kind of action when knocking comes.
Note: This is from our 2005 car but 4th gen ECM should take similar action.
If you by pass the KS, MIL may not light but performance will suffer because ECM will back off timing unnecessarily.
If you use a non-OEM KS, it could work fine but one of the two below can also happen:
1. KS is too sensitive
Then it sends false knock signal to ECM and ECM backs off timing too frequently, performance suffers.
2. KS is not sensitive enough
Then ECM set timing too advance and knocking happens without being detected. In most severe case, engine damage can occur. But you should be able to hear knocking.
08-27-2012, 08:00 PM
#48
Senior Member
Join Date: Jan 2006
Location: Silicon Valley
Posts: 655
That $400 quote is because it is under the intake manifold and the book calls for removing the intake manifold to replace the KS. But no one does that. They just reach in there to replace it without doing all the work the quote book calls for.
08-29-2012, 05:49 AM
#50
Senior Member
Join Date: Dec 2011
Posts: 344
Whoever is saying on here that doing the bypass will still throw the code is completely wrong. If you research and get the correct resistor no codes will throw. (Thanks ChrisMan). I bought a knockoff knock sensor and a OEM sub harness from ebay and the sensor was bad. How do I know, cause I checked it with a voltage meter, and then had my friend check it to to ensure I was doing it right. The harness was perfect. I think I might get one from a junk yard that is OEM (I'll pay a couple bucks if it doesn't see it's way in my pocket first) and test it.
OBTW - This was about 3 -4 months ago and the bypass has been working flawless ever since!
OBTW - This was about 3 -4 months ago and the bypass has been working flawless ever since!
08-29-2012, 07:55 AM
#51
Senior Member
Join Date: Jan 2006
Location: Silicon Valley
Posts: 655
OK, you put a resistor in and ECM sees a signal. It then pushes timing to more advance. The engine start knocking, the ECM didn't see the knocking, still pushes to more advance. Then what? You would risk your engine knocking?
08-29-2012, 09:29 AM
#52
09-04-2012, 01:09 PM
#54
The ECM looks for 470K Ohm to detect a good KS. If you replace a KS with a 470K resistor, it will "see" a good KS and stick to the preset timing maps. The the ECMs' ability to control knocking will be disabled, but running premium and backing off the gas pedal when needed will keep knocking to a minimum.
09-04-2012, 10:31 PM
#55
Senior Member
Join Date: Jan 2006
Location: Silicon Valley
Posts: 655
For being a smart guy in the silicon valley, you spout alot of misinformation. The ECM looks for 470K Ohm to detect a good KS. If you replace a KS with a 470K resistor, it will "see" a good KS and stick to the preset timing maps. The the ECMs' ability to control knocking will be disabled, but running premium and backing off the gas pedal when needed will keep knocking to a minimum.
09-04-2012, 10:36 PM
#56
09-08-2012, 10:32 AM
#58
Junior Member
Join Date: Sep 2012
Posts: 29
got mine at rock auto, $50 with 2 day shipping. Put 460k in resistor bypass to get by emissions inspection. worked like a charm. installed knock sensor today. I wss able to use and extension and swivel to get the old one out but could not fit my hand in the access hole under the intake manifold to replace. so, i cut up an old coat hangar and electrical taped the sensor end to the end of the hangar as well as another location about 4 inches up the sensor harness. this makes re-installing easier because you can bend the coat hangar and direct the entire assembly thur the access hole to get the sensor over the bolt hole while the extension is on the nut. Took off the air cleaner and the connectors to the air intake to give me more room but i had it done in about 10 minutes.
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