2002 Z06. 114k miles. Runs fine minus only getting 15-20 degrees timing advance under load. Mild BTR cam, LG super pro headers, FIC injectors, Vararam cold air intake, FAST90 with LS2 TB, exhaust with no cats.

I keep getting P0332 and P0327 ever since I put on the FAST90 and LS2 TB. Usually throws the code after just one or two drive cycles. I am not sure if it’s coincidental to installing the intake or not but that’s what I started getting the codes. And sometimes P0300 Misfire. Didn’t have any of these codes after doing the previous mods over the last year.

I am pretty sure these codes indicate I have open wiring and/or a bad knock sensor.

knowing I could have damaged the knock sensor harness and knock sensors themselves when I put the intake on. I replaced those first with OEM DELCO parts. I’ve actually gone back and replaced the sensors twice more since then, over the past three months. I have also replaced the PCM and ran a second set of wires in parallel directly from the sensors to the PCM, I soldered and heat shrinked then in 3 inches from the connector on both sides of the harness. I also eliminated the two pin connector between the main engine harness and knock sensor harness to try to eliminate that as a weak point. The one right behind the intake manifold. Everything passes continuity checks

what do you think the issue is? Bad pin/connection at the PCM?? I am stumped and it’s driving me bonkers.

 

That's not a fun issue. I would double check the knock sensors are the correct replacements and that they are torqued right.

 

good point. I’ll check that out. I did torque them to spec but maybe I ordered the wrong sensors.

 

First where did you buy the knock sensors, there are so many counterfeits out there it's unbelievable and you can't tell by looking (packaging, part marking are perfect). Also, without the harness connected to the sensors, you should be able to get a resistance reading (I don't remember the range). if they show open they are bad.

 

If you’re on your 3rd OEM knock sensor it’s probably not the sensor...watch the video and hope it helps...you’ll have to do a little diagnosing instead of firing the parts canon !!

 

I got them off eBay. Here is the link
https://www.ebay.com/itm/202540353487

they appear to be AC Delco. But to your point, they could be bogus. Here’s two actual pictures of one that I received. They were in Delco packaging. . What do you think

[img]blob:https://www.corvetteforum.com/6fcead9e-29c2-4098-b9db-84ee61e93097[/img]

[img]blob:https://www.corvetteforum.com/c60fea93-3a2f-42b7-a93a-de0c2d1250ff[/img]

 

Don’t think an OEM knock sensor would have that sticker “assembled in Mexico” on it...I’d buy one from a Chevy dealer if I were you !!

 

yeah I was thinking the same

 

Yup I’ve been chasing these codes for about a year. I found running e85 Gives me less worry about know or high premium fuels. 91 or better . I also bought those sensors off eBay which I intend to visit the dealer get the harness and sensors start fresh.

 

the eBay sensors I was getting were either defective or counterfeit. I am pretty sure they are counterfeit. I got some from the dealer A few days ago and have not had any issues.

heres some pics of the dealer sensors. Some very slight difference in appearance compared to ebay units pictured above.

fpr example the electrical terminal inside is silver instead of gold. Plating on the body is difference. eBay unit has a raised edge around the circumference of the body. Sticker is different. Crimping on the body is slightly different.

 

Hard to tell, but does the dealer sensor have sticker on it? In that first photo, it looks like it has a white sticker while still in the bag, but I don't see it in your subsequent photos.

 

I wanted to provide some input in the event that it'll help others. My car was illuminating the MIL for a P0332, which is the rearmost knock sensor. I went through the entire troubleshooting procedure in the factory service manual, and all checked out. I should point out that the rearmost sensor was reading on my volt meter, but without a frequency scale to compare output between the rear and front sensors, the voltage reading when tapping the block doesn't tell much, other than the sensors are outputting some voltage.

After removing the intake manifold, here's what I found. The previous owner had replaced both knock sensors; the DTC for the frontmost sensor went away, but the rearmost continued to be troublesome. They have different markings, as shown below. Note, I do not know where the PO purchased these sensors:

Front (notice the crimp size & shape):
https://www.corvetteforum.com/forums...1&d=1590936534

Rear knock sensor (again, notice crimp size & shape):
https://www.corvetteforum.com/forums...1&d=1590936534

I did not want to remove the front sensor for fear of disturbing it, especially after reading that they are sensitive to installation torque (whether true or not). It is worth noting that the breakaway torque on the rear sensor was ~22 lb ft, so the PO overtorqued it - a potential cause for the low output, setting a P0332?

The Rock Auto AC Delco sensor that arrived looked exactly like the front sensor from the top - the crimps were the same, and the finish was the same (slightly less shiny than the rear sensor I removed). I installed it to 180 in. lb. using my 1/4" torque wrench (rather than using my 3/8" at 15 lb. ft. - I don't think the 3/8" wrench is accurate at the lower end of the scale), installed the intake manifold, and voila - no more P0332.

I cannot comment on the notion of counterfeit knock sensors from AC Delco, because my sensors (that are working) are the opposite of the dealer sensors that RathsZ06 is showing, so perhaps it does come down to sensor being DOA, or shipping damage. I suspect quality, because if handling were an issue with these sensors, then AC Delco would package them better - or so I'd like to think. However, I replaced the knock sensor on my '05 Honda CR-V with a Honda part, and it too came in a plastic bag, so who knows?

 

My car only had a code for the front sensor, until I changed both of them, now I have codes for both. I hunted the parts stores and on line, no dealer would warranty that they were ACdelco, even the dealers that were advertising Acdelco. My sensors look like the right hand picture. They have the mexico label which doesn't mean a thing, China ships containers full of parts to Mexico, where they are labeled and packaged. I always looked for the word 'Acdelco' stamped into the metal, these don't have that. I finally fund a NAPA dealer who would give a 3 year, 30,000 mile warranty on his Echlin label parts, so I ordered them, should be in Friday, We'll see.

 

keep us updated. I replace mine with the dealer sensors. Im still getting codes for both. Just don’t pop up as quickly. I ordered one sensor from GMpartsdirect. Waiting for that to come in to try it

 

A long time ago, I was the only Corvette tech at the Gainesville, Fl. Chevy dealer. I went round and round with the parts department that wanted us to use the 'Replaces' brand parts. I did a lot of tune-ups in those days, and gave my customers a 'bring it back if there's a problem' back-up of my work. All re-dos were free! I used to toss the parts department's 'Replaces' stuff in the trash and have NAPA 'Echlin' parts delivered to me in the shop. To me it was worth paying a few bucks out of my pocket for parts that wouldn't come back on me, as the 'Replaces' brand junk did as soon as 500 miles after a tune-up. You couldn't tell the difference between Acdelco packaging and the 'Replaces' boxes except for the tiny word 'replaces' camouflaged on the brand label. In those days top quality ignition parts cost around $4-5, I don't know what they thought they were saving with the cheap parts that didn't last long enough for the customer to drive home. When the service manager called me out on switching parts, I replied, 'What do you want me to do, give the unusable parts to you? I ain't putting them in MY customer's cars. I stopped drawing the bad parts from the dealer's stocks and only charged labor on the work orders, then they made nothing on parts, and couldn't charge for state tax. And I had a 100% customer satisfaction rating from GM for my work at that dealer.

I think the knock-offs are so embedded in the supply chain by now that even those selling QUALITY don't know what they are selling. I've had good luck by finding the original equipment part number for a part, then do a google search online. I kept coming up with a Hong Kong Acdelco dealer, so I tried his parts, starting with OEM iridium spark plugs. The local Chevy dealer wanted almost $20 per plug, I got the same thing from Hong Kong by air mail in 3 days-free shipping for around $50 a set. Just to be sure, I bought a single plug from Chevy, compared it to my Hong Kong plugs, Identical in every detail, including packaging. They even made my engine behave better, very peppy, until I put the damn knock sensors in!

 

any updates on the knock sensors from Napa that you got last week? I stilL have my dealership knock tensors in and throwing codes almost daily now

 

Since the ACDelco 'Labeled' sensors that I bought from Amazon didn't work, and by the time I got them installed the return date had passed, I went with the NAPA 'ECHLIN' parts because NAPA backs them with a 3 year warranty, no one else will give a warranty with electrical car parts. I have installed them in the engine and done resistance and knock testing with a new harness as part of the testing, Since I am getting the proper knock response from both sensors and the connecting harness, if I do have further problems, I can be sure that the installed parts are not part of the problem, and whatever the cause, I can look elsewhere for the cause.

My automotive VOM has a digital readout along with a bar graph that shows tiny fluctuations in the tested signal. The only spec. value I was able to find on knock sensors is that it should be greater than 10 ohms. I tested the resistance of the original knock sensors, getting 100 ohms on the functional part, and 6 ohms on the failed bank 1 sensor circuit that was causing the code. In both cases I could see a fluctuation in the readings when the sensor was tapped with a meter attached, (using a large socket on the engine block in the area of the sensor being tested). I assume that the one with the 6 ohm reading is faulty because its value is out-of-limits (whose limits? what ARE the limits?), and it IS setting a bank 1 code. I went on to test the 2 Amazon sensors, both show around 100 ohms, but very little response to being tapped (only the bar graph shows this). The test readings with the harness connected to these two sensors gave the same readings, little, or no bar graph response to tapping.

Next, I did the same test procedure to the new ECHLIN sensors, both on the bench and installed in the engine with the new harness attached. The old harness did show reliable test response, but visible corrosion on the exposed metal of the connector meant using a new part. I got good response from both sensors and the harness, it was dark by then, mosquitoes are out thanks to rainy weather last week, so I will put it all back together this morning. I will let you know how it goes. Hopefully there is no other wiring or ECM fault involved, but at least I don't have to doubt the installed new parts.

Incidentally, the ECHLIN brand knock sensors are identical in appearance to the original sensors, while the Amazon 'ACDelco' labeled parts are different in appearance AND construction.

 

One other difference is that the Amazon sensors have 'made in mexico' paper labels, while the ECHLIN sensors had no label.

 

My car stopped setting knock sensor codes, 2 days now, before, it wouldn't accelerate even once without setting a knock sensor code. I am still getting 'Low input voltage' from several areas and the anti-lock brakes set a 'low input voltage code' on the left front wheel speed sensor. An alternator test using the scanner sets an alternator 'over voltage' condition also. I am getting the alternator rebuilt tomorrow. I have been suspicious of the alternator since I bought the car in 2016, it will charge the battery unless I drive at night, then the battery voltage drops slowly, and I put it on the charger at home.

 

[QUOTE=sjhanc;1601691474]My car stopped setting knock sensor codes, 2 days now, before, it wouldn't accelerate even once without setting a knock sensor code. I am still getting 'Low input voltage' from several areas and the anti-lock brakes set a 'low input voltage code' on the left front wheel speed sensor. An alternator test using the scanner sets an alternator 'over voltage' condition also. I am getting the alternator rebuilt tomorrow. I have been suspicious of the alternator since I bought the car in 2016, it will charge the battery unless I drive at night, then the battery voltage drops slowly, and I put it on the charger at home.[/QUOT]

Excess AC ripple is what's likely setting the knock sensor and ABS DTC's !!...I've seen it before. A member on this Forum contacted me and said his wife Tahoe was setting both DTC's...ther first thing that came to mind was AC ripple...more than 1 volt and the alternator was smoking hot !!...check it out !!