knock sensor need power?

[93sr20240]

just as title states... i am haveing code 34 show and i replaced knock sensor and still shows code.... im wondering if power goes to knock sensor i check and there is non i also checked from ecu and no signal coming from ecu...

[PoorMans180SX]

Knock sensors don't receive power or "signal".

They are a piezoelectric sensor that takes a vibration and turns it into voltage. This voltage is then transferred to the ECU, which translates it as knock and reacts accordingly.

Is your car running crappy? If not, I wouldn't worry about it.

[93sr20240]

yah running like crap.... on the sr20det faq page it says it recieves 5volts and has 560ohms resistance... im running super rich idle and all

[nismolvr]

Knock sensors don't receive power or "signal".

They are a piezoelectric sensor that takes a vibration and turns it into voltage. This voltage is then transferred to the ECU, which translates it as knock and reacts accordingly.

Is your car running crappy? If not, I wouldn't worry about it.^^^^^^^^^^Wrong!!!! I have searched the web and used FSM and found limited info on how to fix code 34.I found write ups on how to bypass the sensor using a resistor,did not want to go that route ,cause if i did and my engine did begin to ping/knock The ECU would not be able to retard timing ,thus preventing engine damage,just want to protect my investment.
1.code 34 means there is something wrong with the knock sensor circuit.It does not mean your engine is knocking.
2.The knock sensor is a Resistor and should read 560M Ohms.DOES NOT PRODUCE ITS OWN VOLTAGE!
3.on ECU pin 27 (white wire) should produce 5volts with knock sensor disconnected KOEO. KS plug is located between intake runners 3 and 4 disconect it before checking supplied voltage.If OK move on to next step
4.With the KS plug still being disconected check resistance from A (white wire) to engine ground ,it should read 560ohms,wiggle wire connection under manifold ,if resistance changes ,theres your problem,remove KS and check plug and KS for cracks .Replace if ks is out of specs.

This is how the knock circuit works, ECU supplies 5 volts to knock sensor ,KS has a base resistance of 560M ohms when the engine is not knocking.The voltage is stepped down to 2.5 volts (this is normal).The ECU needs to see this 2.5Volts all the time if it doesnt you get a code 34.

When the KS senses knocking vibration or pinging the sensor changes resistance in the circuit ,this causes the Voltage to oscillate above and below 2.5volts.Then the ECU retards timing in order to prevent engine damage.

[nismolvr]

just as title states... i am haveing code 34 show and i replaced knock sensor and still shows code.... im wondering if power goes to knock sensor i check and there is non i also checked from ecu and no signal coming from ecu...
I got your PM. SR and K24 ECU Knock circuits operate the same.If your ECU you shoud have 5 volts going out going directly into K sensor . If Not .Check directly on your ECU with a DVOM .Make sure you ground negative side of Volt meter in a good contact area. Turn key "ON" engine OFF and check for 5V in the assigned KSensor pin.

If your not gettin Voltage ,Replace ECU.

[Memberofthe600hpkaclub]

Or just ground it to the body off the ecu using a 1meg ohm resistor

[nismolvr]

Or just ground it to the body off the ecu using a 1meg ohm resistorProblem is , hes not getting voltage out , so installing a resistor would be useless . Id fix it correctly and not jerry rig it to fool ECU.Especially if he has a turbo.Timing needs to retard , otherwise you run the risk of damaging motor.

[nismolvr]

yah running like crap.... on the sr20det faq page it says it recieves 5volts and has 560ohms resistance... im running super rich idle and all
I wrote that stickie

[93sr20240]

thanks and yah thas why i pm'd you... i ran across your sticky... ill check next time i get to messing with it with a multimeter i was checking earlier with test light and wasnt getting anything out of #27..... i have a rs enthalpy tunned ecu if im not getting any out of ecu would it possibly be in tune or whole ecu?

[nismolvr]

thanks and yah thas why i pm'd you... i ran across your sticky... ill check next time i get to messing with it with a multimeter i was checking earlier with test light and wasnt getting anything out of #27..... i have a rs enthalpy tunned ecu if im not getting any out of ecu would it possibly be in tune or whole ecu?
I dont know what ECU you have but make sure your probing the correct one by studying the pin outs.Never use a test light to check power on ECU pinouts! Always use A DVOM ... 5 volts will not light up a test light set for 12volts..So check it and hope you do have the 5volt reference.

[93sr20240]

ok thanks and its a e5 ecu and im checking #27 white wire