rcknusa

I have replace both front and rear knock sensors and the short harness to no avail. Why does this code keep coming back? The rear sensor actually has oil residue on it and in the hole while the front is perfectly clean. I have had the intake off 3 times and this weekend will probably be the 4th. Does anyone have any idea why this keeps coming back? The check engine light comes on and then I get the code. It almost seems to be speed related, as soon as I hit 65 mph the light comes on. Any help or advice is greatly appreciated

Bill Curlee

Allen

How is oil getting on the sensors?? I would fix that for sure. I have had bad luck with GM connectors. You should probably make sure that the female pins are not damaged and make good connection with the pins on the sensors. If you apply thread sealant to the sensor threads it will desensitize the sensor. Don't know if you want to go that route to try to stop the oil leak!

If the wiring harness is good, it could be one of a couple of things:

- Valve train noise. Do you have an aftermarket cam or lifters?
- Does your valve train make any abnormal noise?
- Do you have any piston slap?


I believe you can de-sensitize the sensor using EFI LIVE or HP Tuners if you have aftermarket stuff causing extra noise.

rcknusa

Hi Bill.
I have no idea how the oil is getting on the rear sensor. I guess is that I do not have the sensor threaded in to the correct torque and maybe oil is seeping through. If that is the case I would think I would get codes for the rear sensor and not the front sensor.

I bought the car used about 3 years ago with a vortex intake but I believe everything else was stock. I traded the stock exhaust with a coworker who had what we believe is a Corsa or BB exhaust.

In the mornings I do hear ticking coming from the valve covers but I thought I had read the noise if fairly normal and not much to worry about. It seems to go away after warming up.

Now how bad have I confused everyone? This just doesn't seem to make any sense. I am temped to put a piece of black tape on the dash to cover up the engine light just because the car seems to run just fine. Seems to have the same power, gas mileage hasn't changed any. Still get 22 mpg combined, 14 city and 26-28 highway.

rcknusa

ttt

SilvaDragon

But you don't know for sure if timing is being pulled because of the
knock sensor, which is very possible, so you could very well be
down on power. Fuel economy probably wouldn't be affected.

Since you are so good at pulling the intake now,
I would go ahead and desensitize the knock sensors and see if
the behavior changes. If it does, you can be pretty sure that
the problem is mechanical, and maybe you need to investigate
that ticking you are hearing. If the problem is exactly the same
using a desensitized unit, then you can be pretty sure the problem
is electrical. At least then you have a better idea what you're
dealing with.

myk7

Is it possible you have a bad tank of gas, or accidentally didn't put 93 octane in it last time you filled up?

SilvaDragon

Gas grade shouldn't matter. If the knock sensors are working properly,
they will compensate for the lower grade of gas without complaining.

The two possible failure modes he is dealing with are:
1 - Mechanical - the computer sees knock all the time from
some engine noise and assumes the sensor is bad.
2 - Electrical - the computer sees the knock sensor return value
out of range either constantly or intermittantly.

dougbfresh

OR he has a lot of carbon buildup causing the "pinging".

torchredfrc

Wow, this issue seems to keep coming back Allen. If I was closer we could get a good scan of your car and (if necessary) desensitize your knock sensors. I must agree with Mr. Curlee above that using some thread sealant might be a good option to try as well as checking the condition of the female connector.

One other option would be to find a 06 with 0% apr and trade her off!

Bill Curlee

Now,,,,,,,,,,,,,,,,I didnt think of that! A can of seafoam is chump change and it only takes a few minutes to do a treatment.

Recommend you try that next.

BC

rcknusa

Thank you everyone. I do not know how to desensitize the knock sensors. I can however pull the intake again, remove the sensors and replace with thread sealant.

I will also do the seafoam this weekend and see how that goes.

Matt, last night after having problems with the lights again I told Margaret I was getting real pissed with this car and was thinking very hard about the deal you are getting and buying her new pickup and me an 06 coupe. We will see though. She still hasn't decided which truck she wants, I even told her you were selling your truck but she seems to keep going back to an F250 I could see the Chevy 2500 but I hate the Ford we have in the back yard now.

I am still without a computer at home until next weed so I will check back in on Monday. Have a great weekend everyone.
Allen

rcknusa

Seafoamed the car last night and smoked the neighbors this morning. Probably woke them up too Took the car for a drive and so far no engine light. I will probably drive it this evening around town and see what happens. Get back with you on Monday.

C5Z0sex

did this work? Old thread I know but I’m going crazy I have taken my intake off 6 times now and replaced the KS 3 times as well as the harness and p0327 keeps coming back. If only it would be as easy as a sea foam treatment.. I don’t even know what else to check. I also don’t see any cut or damaged wires.

would really appreciate any input.

mmartinez

I would start a new thread if you want members to respond.

C5 Diag

After 3X's being replaced I'd say it's not the sensor or short harness. Visual inspection is not good enough...what if you have a broken wire between C112 and the PCM...you're not going to see it without testing !!...you should include all your info in your profile so we know what year, mods, etc your car has...there are differences between model years. I'll include 2 videos below...if you have a DVOM you can check the sensor output on the AC scale. I'm not sure if there is a 5 volt bias on the wire from the PCM to check for circuit integrity but you can unplug the C112 connector and see if there is one...your rear sensor should be good and have that 5 volt bias since it is not setting a DTC..see if there is 5 volts there...if there is a 5 volt bias you will have to get down to the PCM and see why the front sensor is missing it...may be just a broken wire...I'd check right at the PCM to see if it is there 5 volts...you have to go to the source...the front sensor is pin 51 (dark blue) on the C1 connector and rear sensor is pin 11 (light blue) on the C1 connector also. Lastly are they OEM sensors ??…torqued correctly ??…torque is important on these sensors !!

C5Z0sex

Sorry for the late response and thank you for your helpful reply. I did try your suggestions. Turns out I finally decided to “bite the bullet” and get the sensors at the dealership instead of the parts store. (Replaced the pcm and sensor wires for no reason &#128530 and it was the sensors the whole time. Next time I’ll buy straight from the dealer. This has only ever happened to me once before where I bought a parts store replacement alternator and it didn’t read the correct voltage for the pcm’s liking. So I had to buy a dealership one and sure enough it worked. Maybe a difference in ohms I dunno.. anyway it’s fixed. Thank you!

Bill Curlee

Numerous CHINEESIUM Knock Sensors are made so badly and so underhandly that they cant and will not function. Instead of a piezo crystal they cobble in a simple resistor and call it OEM.. Its impossible to know unless you actually tested the sensor with a scope.

On a different note. I always recommend people use ARP Head Studs for any LS head replacement or work. One of my friends did follow my advice and used studs to assemble his heads to the block and one stud stripped out during finial torque. I was shocked and very disappointed. After some discussion, I found out that he ordered a KNOCK OFF, OFF SHORE BRAND head stud kit and not the real ARP Stud Kit. WHEW!! Luckily for him, the threads on TOP of the stud pulled inside the nut. He was able to order ONE real ARP Head Stud back out the damaged stud and keep going on his build. He stated that he will replace ALL the studs later down the road one at a time with real ARP STUDS .

See what CHINEESIUM can do for your engine reliability........ Be careful out there!!

Bill

C5Z0sex

Beyond me already. This is driving me crazy. After replacing the knock sensors and harness multiple times (sensors from Oreilly’s and Autozone), I still kept getting the p0327 code on my 2001 z06. The car is stock besides a cat back borla exhaust. I even went as far as rewiring the knock sensors with a new harness pigtail and ran the new wires strait to the pcm (a little extreme to bypass the originals, I know, but wanted to be sure there was not a short in the stock harness) and p0327 still came back. I bought a replacement pcm programmed for my car and still p0327 H C came back. I finally went and bought oem sensors at the dealership and the code finally went away (but only for 2 weeks). My smog pump relay was removed ( from being tuned out on the original pcm ) so the check engine light came on for that but no p0327. I also had a code for a oxygen sensor heater. I cleared the codes, put the relay back on for the smog pump and went for a drive. Now p0327 came back on!! 😡 The sensors were torqued to spec when installed and the harness was new. I’m going crazy with this issue now. I’ve replaced everything that I know of involved in that knock sensor system. Anyone else had this issue before? The car is all stock now except for the catback. I would appreciate any advice on what to look at next.

C5 Diag

I’d look at taking your car to a diagnostic shop…you’ve replaced all the wiring right up to the PCM so let them throw a scan tool on the car and see if you really have a mechanical issue which is setting the DTC…they should be graphing the timing with the scan tool and see if it is retarding your timing while driving and setting the code.

Bill Curlee

Here is an EXCELLENT You Tube id on how to test and trouble Knock Sensors!


Go to the PCM connector, find the KN Sensor wires and tap on the block just below one of the sensors and look for a voltage increase. Test both on the lowest AC Scale that you have and see if you are getting ANY signal at the PCM connector.

Bill.