Strange issue with coce P0325 Knock sensor

[integra123]

I recently did an engine transplant along with changing timing belt, water pump, and oil pump. I have this problem with my knock sensor and cant figure it out.

I've tried two used sensors already and they are doing the same thing. Basically it will be good when you reset the ECU. After driving for a day or two the light would come on.

This is what I notice the pattern:
1. Engine light is on. I take my kids to the baby sitter in the morning and she is about 6 miles away.
2. Drop the kids off. Start the car and drive about 100 feet and the engine light goes off.
3. Drive to my work which is about 11 miles away. Upon making a quick right turn on a street near my work, the engine light would turn on again.

This pattern has happened two times, that Ive started to notice. It seems like a somewhat hard right turn causes the engine light to turn on.

My question is...can it be a bad knock sensor, or does it have something to do with my knock sensor wire?

[Mister_Perkins]

P0325

DTC Condition:

No signal of knock sensor 1 to ECM with engine speed between
1,700 rpm and 5,400 rpm

trouble area:

Open or short in knock sensor 1 circuit
Knock sensor 1 (looseness)
ECM

This sensor contains a piezoelectric element which generates a voltage when it becomes deformed, which
occurs when the cylinder block vibrates due to the knocking. If engine knocking occurs, ignition timing is retarded to suppress it.


====

I would check the plug, trace the wires checking to make sure theres no cracks or shorts (Wiggle test -- Wiggle the plug wire to see if you throw a code .. this will confirm a bad wire)

The bad thing is it can only be tested by exciting them with a frequency sweep(and typically high voltage). Each different type of sensor has different frequency 'modes', which is steps of frequency at which they will resonate. Even knowing the exact modal frequencies of a piezo electric actuator/sensor, it is still very hard to distinguish mechanical stresses and fractures in the material.

If you have a scan tool with datastream, you can monitor the knock sensor with an oscilloscope, watching the wave forms, and monitor the air fuel ratio with the obdII scan tool and freeze the data when the problem occurs. Since you probably don't have an oscilloscope .. Its hard to diagnose.

I would recommend the Wire wiggle test first though, that will tell you if you have a bad wire anyways. "hopefully thats the case"

[fenixus]

if wiggling wires doesn't help, try this.

I would get the OBD2 ELM327 interface/cable for a PC laptop off ebay ($20-40).
ScanMaster or Digimoto V should allow reading the Freeze Frame data, so:

a) reset the ECU and start driving

b) once the lights comes up, scan it, read the freeze frame associated with this error code, write it down (including what you and car were doing while it lit up), reset the ECU

c) drive it again until it comes up, again scan the freeze frame data, write down (including what you and car were doing while it lit up)

d) do it a few times to collect "enough" freeze frames

e) compare them to see if there is anything common to all them (specific RPM, specific temperature, specific fuel trim or oxygen sensor reading, etc.)

hope it helps.

P.S.

also consider switching to higher octane fuel, I don't know what you are feeding the car with, but if that's regular maybe it's quality went down the hill recently.

[integra123]

Thank you so much guys. I will give everything a try. I'm going to borrow my friends SNAP ON Scanner. I'm sure it has everything on it.

I've been running 87 octane from Conoco Phillips 76.

[reluctantmechanic]

this is going to sound silly, but is the engine knocking at all?

[Mister_Perkins]

Originally Posted by fenixus

I would get the OBD2 ELM327 interface/cable for a PC laptop off ebay ($20-40).

Very useful information

Thats cheap, and still gets the job done!

[Chris Crash]

Try 89 fuel, but mostly check your wire. It might even be a problem with your ECU.

[Chris Crash]

Are you using a Toyota knock sensor? Aftermarket knock sensors make these cars unhappy.