BNastee

Reminders: I'm still on the first ten gallons of the PEA treatment. Changed the rockauto knock sensors out for some old originals. Confirmed the sensor wiring.

New info: Got a short test drive in after the starter swap and we have improvement! Only one knock sensor code is popping! That might be stranger than both of them.

Path Forward: I'll run a second ten gallons with PEA additive through the car and watch for changes. Then I may wire both ECU inputs to the knock sensor that is not popping a code. That's what I did with my 2000 LS400 #TexasLexus.

aptoslexus

You were running Rockauto knock sensors? That's probably a guaranteed fail. Rule of thumb: never ever run non-factory knock sensors.

400fanboy

I'd say that for any sensor. They're all really affordable. It's only as a last resort if the part is out of production - I'd even run a used sensor before a cheapo offbrand one. For any sensor, coolant, vvti, cam, crank, all of em.

BNastee

This knock sensor CEL happened on the originals to begin with. No change when i put in the rockautos a few years ago. Improvement noted in my 12-01-2023 post that could be from a random set of original sensors or from the PEA fuel additive.

I shouldn't have made two changes at once, but the starter plunger was hanging up pretty often.

Lexicon1

How does one follow a post, sorry to ask in this forum posting.
IF I "like" this post, will I automatically get an update when the thread continues"

BNastee
You mention PEA additive. Ive used Techron (concentrate and non concentrate) for years.
About a year ago, my 254k mile Toyota started consistently getting 24 mpg when it normally would get 28-29 mpg.
I had changed plugs etc etc for low gas mileage issues and the only thing that was left was fuel injectors/carbon deposits. I tried Techron twice. No change.
I tried one can of Royal Purple Max Clean and within two weeks my gas mileage was back to 28-29 mpg consistently. I saw Scotty Kilmer use it on his channel and since Techrnon was not working, this seemed to get the job done. It supposedly also addresses combustion deposits. Not saying yours is a carbon deposit issue. Just saying for me, this product really worked. Side note, your rodent issue took out some copper wiring. Is there a possibility there could be more damage not easily seen? Fascinating troubleshooting issue. Good luck.

BNastee

Good morning Lexicon. Thanks for sharing your experience with RP Max Clean. I work from home and don't put much gas through the car. I'm still on the first ten gallons with PEA!

Other wiring issues are very possible. Good point. My visual inspection and resistance check of those two wires in particular have me confident but you never know!

BNastee

I never finished the second tank with Techron. Early results were inconclusive because I changed to a pair of used knock sensors during the first tank of Techron. Only one sensor popped when it did. Was previously both at the same time, every time.

The car is with its' next teenage driver. I'll maintain the car for them, a family friend. I had the code cleared during the testing so I'd be very glad if it came back in a month or so with it still off!


Rich

clipster

@BNastee How did you verify the wiring? I've got a knock sensor CEL even though I replaced them with OEM 10 years / 40K miles ago when I replaced my starter, and the knock sensor wires go into a plastic box attached to the starter that I'm unable to open or remove.

BNastee

I had the intake off and checked continuity from the knock sensor plug back to the correct pin on the ECU.

If I were you, I'd follow what Yamae said regarding the fuel additive first.

I'm curious - if you clear the knock sensor code under what conditions does it come back on? Mine would stay off until I was accelerating on to the freeway. Every time.


Rich

clipster

I never cleared the code, for I assumed that if it came on there had to be a reason. The CEL came on at low speed / low RPM at the end of a 65 mile drive.

After pulling the intake manifold I found a bunch of seeds that weren't there when I replaced my starter 10 years ago. Strange since I keep my car garaged - I figured it must have happened over the last eight years when i left the car outside overnight at my girlfriends house. Nevertheless, the wiring appears to be undamaged.

I tried to verify the wiring from the connector to the ECU, but couldn't get a connection for either the left or right bank using pins 17 & 18 on E14 per the FSM. However, I did notice broken plastic inside the left bank connector (which the CEL was for - P0325)

I'm now considering buying aftermarket knock sensors on ebay solely for the connector on the included pigtail. Does anyone have any experience with these? I thought I read some where that OEM connectors are NLA.

TominPT

Check out the wiring fix Car Care Nut does on this truck - might give some ideas on how to make it work with your broken connector (he uses a new connector from another vehicle).

BNastee

Interesting timing for your knock sensor code to pop. Its a fun investigation to get a scanner with Live Data and watch the engine timing on a graph around the time the code pops. In my experience the car runs way down on power (due to timing) with the code popped.

I have a couple junkyard engine harnesses and would be happy to look and see if they still have knock sensor connectors.

clipster

Thanks for the offer BNastee

I ended up buying a couple of these connectors from Parts Geek, since they seemed to be of better quality than the generic ebay options: https://www.partsgeek.com/nhfcbcy-le...connector.html

Ordered on Sunday and received them today, so happy with that. Appears to be well made, and has a snug secure fit. Turns out this company makes a lot of electrical parts for our cars - check them out at standardbrand.com

Of course I'll be soldering the wires instead of using the included crimp connector, along with shrink tubing and a new wire sheath.