Code 52

[Jetfixr757]

Ok, so i get a code 52 after messing with a boost controller and a Rebic LC, clear it, it comes back, removed the Rebic, stock boost set, cleared it and then started the car, it came back within 3 mins, ok, so which knock sensor do i change? How can one t/s to isolate the knock sensors? Do you just change them both? So this is the question? The wiring harness for the engine is just barely a year old, all connectors and wiring is new, and no chaffing. Do you think the ECU is cooked. Just scratching my nogin, how does one bench check a knock sensor? I guess there must be a resistance reading you can use to check to see if it is good or bad.
William 89T
p.s. 16lbs of boost really wakes up the beast. My gosh.

 

[Supra Blues]

Actually you are looking for voltage.

When the knock sensor is working properly it will output milivolts.

If you want, you can bench test it as follows:

Hook up your voltmeter to the knock sensor and set you voltmeter to milivolts, don't remember if its A/C or D/C though. You can tell cuz one will constantly send your voltmeter jumping.

Slightly tap the knock sensor. If, when you tap it, you see a volt spike, your knock sensor is most likely working just fine. If not, double check that you have the knock sensor hooked up correctly and try again.

See also:

http://www.supramania.com/forums/showthread.php?t=4072&highlight=knock+sensor+test

 

[shaeff]

that being said, KS's rarely go bad, but they do on occasion.

-shaeff

 

[Jetfixr757]

Well as it turns out, i swapped the fwd knock sensor from my old engine and low and behold, no fault codes and light is out. But on the down side i roasted the turbo at the track tonight.
William 89T

 

[Sonex2000]

Why is the ECU rewiring nessesary?

 

[shaeff]

Why is the ECU rewiring nessesary?

because when there's a short in the circuit (which there frequently is because the wires are kindof crappy, and they're damn old) the ECU cannot "see" the knock sensor(s). when this happens, the ECU puts out a code 52 and retards the timing, and enrichens fuel mixture.

this is considered a "safe mode". to rid ourselves of the problem (code 52), we rewire the knock sensors with good shielded cable (coaxial) to prevent any "electrical noise" from interrupting the signal, thus causing the code to re-appear.

-shaeff