More Dreaded Knock!!!! LONG Post

[MidnightGT]

Well guys, my quest for a 9 second DD is being haulted by some unknown knock.

As for my car.

2015 Auto. VMP stage 3- twin 67mm tb, id 1000's, Sai Li fuel system, e85, MBRP h pipe and mufflers.

A little history. I installed this kit as a stage 2 in November, initially logged ZERO knock on 93. Ran it this way for months and then decided to do a few more things

Added performance pack shocks/struts, steeda progressive springs, sai li fuel system, and id1000's for e85 all between my zero knock log and now.

Now I have knock on almost every pull, however I will get zero knock intermittently. Because I have done so much from one good log to now, I don't know where it could be.

I have looked at all exhaust and tightened and re-checked every nut and bolt. I have looked at all suspension to make sure nothing is hitting. I have stripped the front of my car down to make sure nothing is banging.

Today I switched plugs from Brisk 1 stage colder to NGK 6510's just to see if that somehow was an issue, but it didn't change anything. Next I'm going to just pull the supercharger, check all lines, knock sensors themselves, and give a final attempt at finding the cause.

I have tested the e85, always testing at 70% or better ethanol. Even with the good Houston 80%+ ethanol it was doing the same thing..... Starting at 20* spark advance and dropping to 11* due to the knock at times.

Anyone able to give any advice?
Any help would be greatly appretiated.

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[MidnightGT]

A pic of some of the log info @ peak knock on this log

 

[Dennisn]

i know it's not the preferred way but as long as your on e85 can you just turn the knock sensors off? Maybe talk with your tuner. I'm just not sure what the e85 has to test at before turning them off. I ran that way last year and just made sure to test every tank I put in the car and would test at a min 85 e content.

 

[MidnightGT]

i know it's not the preferred way but as long as your on e85 can you just turn the knock sensors off? Maybe talk with your tuner. I'm just not sure what the e85 has to test at before turning them off. I ran that way last year and just made sure to test every tank I put in the car and would test at a min 85 e content.

Who did you get to turn them off? I think it is very rare to get them turned off by a tuner. However I'm up for anything at this point. I did ask my tuner if he could desensitize them (which I have heard can be done), however he just asked for more logs...which I'm getting this weekend. Maybe he can find something through the logs that can point me in the right direction as I am getting desperate at this point.

 

[Dennisn]

You'd be surprised it's probably done more than you think. I probably spent half the summer trying to get rid of mine and could not no matter what I did. I was ready to burn the car down. Was actually upset when I finally asked the tuner if we could shut them off and he said sure. Was like wtf, I spent two months trying to fix something there was a workaround. Again I'm fully aware fuel quality is important and would test every tank.

 

[MidnightGT]

You'd be surprised it's probably done more than you think. I probably spent half the summer trying to get rid of mine and could not no matter what I did. I was ready to burn the car down. Was actually upset when I finally asked the tuner if we could shut them off and he said sure. Was like wtf, I spent two months trying to fix something there was a workaround. Again I'm fully aware fuel quality is important and would test every tank.

If nothing comes of this weekends logs I will ask my tuner. Hopefully it doesn't come to that, but we'll see

 

[olaosunt]

Make sure your block is not cracked around the sensor.
I had similar issue in my KB while tuning last year.
Ended up turning down knock sensitivity(also had him do a tune for them off but....just in case).
Car made great power.....but started loosing coolant eventually due to crack(not visible) around drivers side sensor.
I am wondering if that had been the cause all along.

 

[olaosunt]

You'd be surprised it's probably done more than you think. I probably spent half the summer trying to get rid of mine and could not no matter what I did. I was ready to burn the car down. Was actually upset when I finally asked the tuner if we could shut them off and he said sure. Was like wtf, I spent two months trying to fix something there was a workaround. Again I'm fully aware fuel quality is important and would test every tank.

Mine has been off in my car(TT) from day one(with tuner) but now starting to wonder after 2 engine failures if this a great idea.:frosty:

 

[MidnightGT]

Hmmm.... getting them turned off is definitely something I'll run by my tuner, but I'd like to use it as a last resort. I may just break down the entire top of my motor to the sensors tomorrow just to check everything out.

Any other input is still greatly appretiated!

 

[Super Werty]

Maybe the sensors themselves are damaged. Get some new ones and try them out

 

[dubster99]

It shouldn't be pulling spark at 20*...something is funky. Make sure nothing is hitting, make sure your O2 sensors are tight, everything. If the sensors were damaged, I'd assume you wouldn't get a reading at all. Post your whole log if you can, or show the graph. Is there anything that correlates between your logs? Like the knock starts at a certain RPM every time?

 

[MidnightGT]

The knock is random. Here is the graph of the above posted log. I removed a few logging items to attempt to clean it up a bit. But as you can see. I get a little negative knock on the hit and it climbs with rpm.

 

[markmurfie]

Hit the windows key and type snip. use the snipping tool to take a screen shot of a selected part of you screen. That picture is hard to see the different colors. it looks like your measured AFR are not dropping down until later in the pull but that could be a cat over temp protection. hard to tell. better yet post the .csv file.

 

[sonic]

Make sure the AC line is not hitting the header on the passenger side.. try to use a GoPro under the hood to see if you can spot anything

 

[MidnightGT]

Hit the windows key and type snip. use the snipping tool to take a screen shot of a selected part of you screen. That picture is hard to see the different colors. it looks like your measured AFR are not dropping down until later in the pull but that could be a cat over temp protection. hard to tell. better yet post the .csv file.

I cannot post the .csv on here through the attachments file, and I tried saving it via .pdf and posting it, but the file was too big. I will try to shrink the file to the pertintent info for .pdf and see if I can do it that way. Thanks for your help

By the way, this is a different log that shows even more KNOCK! So, I don't know if there may be a trend that can be spotted, but as you can see, the knock just steps up as RPM's increase.

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