Turbo 5VZ... P0325 Haunting me!!!

[Sean-Himself]

I have a '98 4Runner, 5VZ that I recently turbo'd, I have been getting a p0325 knock sensor code that just won't go away. I have a brand new OEM KS harness, I have de-pinned and swapped pins at the timing cover connector (EB1) and the codes swapped to the P0330 so it makes me think I have a wiring issue.

I decided to make a temporary GM KS mount/conversion to see what happened. Still pick up the P0325. So, OEM sensors and harness are bypassed. I OHM'd both gray and black KS wires back to the ECM, they tested good. I OHM'd my home made harness to the GM sensors (good). I tested the GM sensors for resistance and AC voltage (good). I am at my wits end and out of ideas at this point. Looking for help/suggestions!

Thanks!

 

[gamefreakgc]

I have a '98 4Runner, 5VZ that I recently turbo'd, I have been getting a p0325 knock sensor code that just won't go away. I have a brand new OEM KS harness, I have de-pinned and swapped pins at the timing cover connector (EB1) and the codes swapped to the P0330 so it makes me think I have a wiring issue.

I decided to make a temporary GM KS mount/conversion to see what happened. Still pick up the P0325. So, OEM sensors and harness are bypassed. I OHM'd both gray and black KS wires back to the ECM, they tested good. I OHM'd my home made harness to the GM sensors (good). I tested the GM sensors for resistance and AC voltage (good). I am at my wits end and out of ideas at this point. Looking for help/suggestions!

Thanks!

Did you wire in a piggyback controller? Double check the right wires were cut and spliced and the knock sensor wiring to the ECU was not damaged.

 

[Sean-Himself]

Did you wire in a piggyback controller? Double check the right wires were cut and spliced and the knock sensor wiring to the ECU was not damaged.

I did wire up an FIC6. I have checked them over and over, I did NOT tap into the knock wires and I have not seen any damage. I am only getting the "right bank" code and not the left. I never get the P0325 at idle or "neighborhood" speeds. I very rarely get it around 40 MPH and I always get it on the freeway around 60 MPH. Some days I may not get the code and other days it comes on as soon as I clear it.

 

[Silver Supra]

I did wire up an FIC6. I have checked them over and over, I did NOT tap into the knock wires and I have not seen any damage. I am only getting the "right bank" code and not the left. I never get the P0325 at idle or "neighborhood" speeds. I very rarely get it around 40 MPH and I always get it on the freeway around 60 MPH. Some days I may not get the code and other days it comes on as soon as I clear it.

Maybe it's truly knocking... what are the A/F's, octane, boost, etc? Have you tried pulling some timing and/or adding fuel?

 

[gamefreakgc]

Maybe it's truly knocking... what are the A/F's, octane, boost, etc? Have you tried pulling some timing and/or adding fuel?

The problem is, it doesn't throw that code when it knocks. It only throws that code or the P0330 code when there's an issue with communicating to the sensor.

You've got an issue with the wiring, or the sensor itself. Seeing that you only replaced the harness and not the sensor, my money's on the sensor gone bad. Installing a relocated GM sensor doesn't mean that your current knock sensors are good, since the GM sensor is rather untested and only a few have successfully got it to work without throwing a code.

I still think a wire could be pinched or damaged. I was helping a friend diagnose a low coolant temp CEL that was very odd, and turned out it was his wiring on the piggyback controller. Only solder wires to the ECU, never use wire crimps.

 

[Sean-Himself]

Maybe it's truly knocking... what are the A/F's, octane, boost, etc? Have you tried pulling some timing and/or adding fuel?

Well, when the code comes on the most during freeway driving around 60MPH the AFR's are 14.2 and 15 (Narrowband). I use 92 octane. Not in boost when it happens (cruising, usually around -10), I have 2 steps colder plugs, 170 T-stat. I haven't pulled timing because it was never an issue before, especially while cruising. Have not added fuel because again, while cruising the AFR is fine. I don't believe it is knocking only because if I swap the KS pins with each other, the code jumps to the other bank (follows the wire)

 

[Sean-Himself]

The problem is, it doesn't throw that code when it knocks. It only throws that code or the P0330 code when there's an issue with communicating to the sensor.

You've got an issue with the wiring, or the sensor itself. Seeing that you only replaced the harness and not the sensor, my money's on the sensor gone bad. Installing a relocated GM sensor doesn't mean that your current knock sensors are good, since the GM sensor is rather untested and only a few have successfully got it to work without throwing a code.

I still think a wire could be pinched or damaged. I was helping a friend diagnose a low coolant temp CEL that was very odd, and turned out it was his wiring on the piggyback controller. Only solder wires to the ECU, never use wire crimps.

Exactly right, I ONLY get the P0325. Unless I swap the KS wires with each other. Then I get the P0330, so the issue lies in the wires. I soldered all my piggy back wires. (Again, KS wires were not tapped).

I OHM'd from the ECM connectors to the EB1 connector behind the timing cover and there was 0 resistance on both bank 1 and 2 KS wires. I tested the GM sensors for AC voltage to make sure they are working (They produced voltage as they should).

Even with the factory KS and KS harness connected I was getting the P0325, Then I made the temporary GM sensor mount and harness, same code. Also OHM'd my home made harness which was good.

 

[Silver Supra]

Gotcha, then it does seem like maybe a wiring issue. Electrical gremlins suck!

 

[rideexileex]

Exactly right, I ONLY get the P0325. Unless I swap the KS wires with each other. Then I get the P0330, so the issue lies in the wires. I soldered all my piggy back wires. (Again, KS wires were not tapped).

I OHM'd from the ECM connectors to the EB1 connector behind the timing cover and there was 0 resistance on both bank 1 and 2 KS wires. I tested the GM sensors for AC voltage to make sure they are working (They produced voltage as they should).

Even with the factory KS and KS harness connected I was getting the P0325, Then I made the temporary GM sensor mount and harness, same code. Also OHM'd my home made harness which was good.

Don't trust the ohm readings on the sensors - my BAD sensor ohmed out perfectly fine on the bench. If your codes are switching when you move the wires, I would suspect the sensor is failing.

Also, for diagnostics, the knock sensors only pick up at above 3k RPMs.

 

[Sean-Himself]

Don't trust the ohm readings on the sensors - my BAD sensor ohmed out perfectly fine on the bench. If your codes are switching when you move the wires, I would suspect the sensor is failing.

Also, for diagnostics, the knock sensors only pick up at above 3k RPMs.

New theory. What if one of my OEM sensors failed creating my P0325. Everything "tests good". I rigged up the GM sensors and somehow (my luck) I wired up a bad GM sensor to the same wire as the bad OEM sensor, thus creating the illusion that I have something else going on... :redbrick:

So, I will plug in the factory harness and sensors. De-pin the black KS wire at the timing cover connector (EB1) and wire in my suspected "good" GM sensor on the opposite bank that isn't throwing a code.

According to TIS, for my specific vehicle, the ECM looks for the knock sensor signal between 2k and 5600 RPM.

2019-01-08_08-39-20 by Sean Miller, on Flickr

 

[gamefreakgc]

New theory. What if one of my OEM sensors failed creating my P0325. Everything "tests good". I rigged up the GM sensors and somehow (my luck) I wired up a bad GM sensor to the same wire as the bad OEM sensor, thus creating the illusion that I have something else going on... :redbrick:

So, I will plug in the factory harness and sensors. De-pin the black KS wire at the timing cover connector (EB1) and wire in my suspected "good" GM sensor on the opposite bank that isn't throwing a code.

According to TIS, for my specific vehicle, the ECM looks for the knock sensor signal between 2k and 5600 RPM.

Yeah, that's what I was trying to say. I think there's only what, 2 people on customtacos.com that have said they use the GM sensor? How many other people tried it but it didn't work? Can't use the GM sensor as proof that it's a wiring issue.

 

[Sean-Himself]

Yeah, that's what I was trying to say. I think there's only what, 2 people on customtacos.com that have said they use the GM sensor? How many other people tried it but it didn't work? Can't use the GM sensor as proof that it's a wiring issue.

From what I have read and understand is that it is more popular with turbo 5vz guys. I've heard about a lot of guys using them and not having issues. ATM I don't think I have read about somebody using the GM sensors and them not working. But I suppose we will see!

 

[Sean-Himself]

Update. I believe to have figured out my knock sensor issue. First issue that threw me for a loop was that one of the new GM knock sensors was bad out of the box... Second, my home made temporary KS mount was causing issue. The way I had it mounted allowed for enough vibration to throw a code. I re-mounted the sensors so that there would be less vibration and I have been code free for about 2 weeks... What a mess