Nomad4g63

iTrader: (16)

So i went yesterday to get my car tuned by Jestr, and the car would log 36 counts of knock 1 run. Then no Knock on the next run and would not respond to timing. Car was also knocking while @ idle revving past 3800 RPMs 8-9 counts of knock. So we thought OKAY something simple, Bad knock sensor. So we took off the plug off the knock sensor in the car and plugged it into ANOTHER knock sensor Mike had laying around in his shop, we wrapped in a towel and placed it on the wind shield, where there should be absolutely no Knocking.


So we started the car back up and revved the car up again @ idle and once again 8-9 counts of knock @ 3800 rpms. WITH THE KNOCK SENSOR WRAPPED IN A TOWEL ON THE WINDSHIELD! So with quick thinking and help of course from the staff @ AWD Motorsports, we tried swapping out the Stock ECUs to see if it was a bad ECU problem. We swapped it out, Jestr loaded the tune, and once again! With the knock sensor still on the windshield KNOCK KNOCK @ 3800 rpms.

I officially don't know what is wrong with my car and how to find a solution. Does anybody have any ideas, related problems, or suggestions you'd like to throw out there Please do me the favor and post.

hempele28

iTrader: (28)

Had a very similar issue when I went yesterday for my petey turbo tune. I ordered a new knock sensor yesterday but I'm subscribing to this thread to see other possible fixes.
At one point just revving the car I got 20 counts. I need a fix because its killing my tune.

Mellon Racing

iTrader: (38)

how does the condition of the knock sensor wiring harness look? on the old 3000/Stealth's, the wires would crack open, turn green and false knock like that.

Nissan2Evo

iTrader: (23)

What does the knock graph look like..if it spikes 36 then does down in a stair like fasion it may be a boost leak. Each time I noticed high ridiculous knock counts like that we check for leaks in the piping, BOV, IM..etc. After fixing the leak the issue goes away..something to consider.

Nomad4g63

iTrader: (16)

well i did have a SAFC wired to the stock ECU when i bought the car. It was cut and plied into the stock ECU harness. But since then i have taken the SAFC out, and the wires were saudered back together.

Nomad4g63

iTrader: (16)

maybe but remember with the Knock Sensor on the windshield there should be no knock @ all.

Mellon Racing

iTrader: (38)

was the safc wired into the knock sensor?

Nomad4g63

iTrader: (16)

i don't know, which is the knock sensor wire color?

Mellon Racing

iTrader: (38)

I don't remember

Nomad4g63

iTrader: (16)

I dunno what to do, AWD motorsports mechanics said the only thing they can think of doing is replacing the whole ecu wiring harness, and see if the problem goes away. But thats a very costly thing to do, and it might not even be the problem

Mellon Racing

iTrader: (38)

it does act like there's a wiring problem and if that knock sensor wiring was tampered with to connect it to the S-AFC to monitor knock voltage (which is useless) that may very be what's causing your ECU to pick up false knock.

Nomad4g63

iTrader: (16)

Here might be another interesting fact. In December i had a big short, where my turbo outlet pipe touched my ignition and fried alot of my wires. When we checked the ECU wires all wires looked fine no burns. And i have been lately having problems where when i try to turn on my car it takes a few times to have it start. I dunno if this might be related to the false knock im getting.

TTP Engineering

iTrader: (465)

The knock sensor requires being grounded to the block. Putting it on the windshield did absolutely nothing. When its not grounded it will register 8-9 counts all of the time.

Nomad4g63

iTrader: (16)

now come to think about it, my SAFC was reading voltage and alot of other specs.

Mellon Racing

iTrader: (38)

I thought the knock senor had a ground wire on it already