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First time post here. Long time lurker!!! This forum has been a huge resource and help. I have swapped an LS1 in my 1996 G30 Chevy Van. ....and now I just completed a 5.3 LS swap in my 1990 FJ62 Toyota Landcruiser. I have a few minor issues and need a little help.
Donor engine is from a 2006 Tahoe 5.3L and its swapped in my 1990 Landcuiser. I rebuilt the engine on the stand prior to install and added a Texas Speed Low Lift truck cam (stage 2). During the rebuild I used new GM knock sensors and the harness. I used the original Tahoe LS wire harness and swapped out the original PCM (Service number 09354896) for an Ebay purchase Service number 12602801 (because it has the 12VDC+ A/C input to idle up during A/C). Mailed out the new PCM for the tune and cam.
The Problem
I currently have a running driving swap, but I have 3 Codes: P0651, P332, P327. So I understand its both Knock Sensors ( I have read the threads out there, and its not looking good). The 651 is the 5V reference.
Please give me recommendations to fix the issues, I am leaning towards the PCM since it was an ebay purchase. I have checked wiring in all directions:
Knock Knock
No shorts to ground in Harness. To PCM and To sensors
Knock sensors both show 99 ohms resistance while engine off
Knock sensors show producing some voltage Ac and DC when engine is running.
Both Sensors and Harness replaced with AC Delco parts.
(Are there a lot of fake parts for resale on the internet, I saw some are having better results with local parts store sensors (Dorman, ETC?)
I pulled the intake back off, and checked the sensors, I loosened and retorqued the knock sensors at 11 ft/lbs. I have seen 11 and 15.....but too much causes issues. I have heard if they are dropped or mishandled they have problems, but like I said, they check out with a multimeter.
5 VDC Reference
Theres a youtube video of a guy diagnosing this and shows there are 2 codes. P0641and P0651... I have 651... in this video he is saying that 651 code is for APP Sensor 1(accel position pedal), TP sensor 1 & 2 (throttle pos), CKP Sensor (crank).
First off, I have drive by wire. 24x P59 PCM..... if my west virginia public school education is correct. my Crank position sensor is 12V power (the 58x stuff with the gray sensors. transitioned to 5V). so that shouldn't be my issue.
I have heard the DBW Throttle body has imbedded TPS sensors..... my 5V ref checked good. Pin E on my 8-pin connector showed 4.99V (key on, engine off) and the pin E did not have continuity to ground
I checked for 5VDC on the oil press sender, the MAP, and the Throttle body. All had. 4.9-5VDC at the connector and no short to ground in sensor or harness.
EVAP Purge solenoid was 12V not 5.
All codes turn the MIL Check engine light every start. It doesn't appear to be pulling timing.... shitty phone app, but I see timing advancing to 40 at times and don't hear it being cut. but deff doesn't have all the power it should.
5.3 fits in the Cruiser. Intake came back off, double checked the new Knock sensors and harness New OEM AC Delco Knock Sensors...could they be knock offs?
Sorry about the crocs, thanks for the help!!!Talking
It seems the Delco Sensors, Delphi, and Dorman all do not output ENOUGH voltage and it believes the sensors failed. I tried them straight from the Dealer, Summit, Parts stores etc.
It got to a point after two I tested my one good knock sensor with a vice, hammer (to hit the vice), and a Volt Meter to measure things instead of installing them and having to redo it.
Well turns out NAPA Parts has the only good sensors I could find
Link Here the Part # is ECHDKS238
No Knock Sensor issues in 20k miles since I installed them in early 2024.
thanks man, yea I think that’s it! I got a second set of AC Delco sensors from summit & they fixed it. I’m gonna screen shot this and keep those Napa part numbers handy but crossing my fingers that I’ll be good for a while, it’s been running good. I’m just going to disable the CEL for the stray 5v ref low, everything else is working.
Originally Posted by Live Fast 117
I went through this same issue on my C5Z.
It seems the Delco Sensors, Delphi, and Dorman all do not output ENOUGH voltage and it believes the sensors failed. I tried them straight from the Dealer, Summit, Parts stores etc.
It got to a point after two I tested my one good knock sensor with a vice, hammer (to hit the vice), and a Volt Meter to measure things instead of installing them and having to redo it.
Well turns out NAPA Parts has the only good sensors I could find
Link Here the Part # is ECHDKS238
No Knock Sensor issues in 20k miles since I installed them in early 2024.
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Another 5.3 Knock sensor and 5 volt reference ?? 
