E85 Knock :( Any suggestions on log

[BoostedBeaver]

Ok so I just installed some 2150's and was going back through the motions to make sure that everything was still in line.

I started by doing a short pull to 5500 to insure global was right, then I set the idle and did a cruise. After all this lined up, I started doing pulls to dial in the VE table. I would make a pull make small and minor adjustments where needed, and make another pull to confirm. I started at waste gate pressure (18lbs) then 22psi then 27psi.

I made one pull on 27psi and made some minor adjustments to make afr's match a little better. Once these changes to the VE table where made, I made one last pull. This pull was cut short by knock. This was my last pull (last suitable stop on my route) so I did not do another pull to confirm, but now I can get knock while free reeving.

Again all of the settings from one log to another stayed exactly the same except the small changes to the VE table. First log is the first clean 27psi pull, 2nd log is the log that caught knock and the third is 2 steeping in the driveway after catching knock.

Any suggestions to a possible solution that I may have overlooked will be greatly appreciated. I had great AFR's, 12 degrees of timing at 4100rpm when this happened. I am leaning towards a bad or loose sensor (motor is still hot at the moment so I can not check to see if it is tight and the sensor is 8 months old) but if you see anything that looks remotely out of place, please let me know.

Thanks
Robert

 

[Arthris]

Hmm I cant view the logs as i don't use link. But sounds like either a bad or loose sensor as you said or the E85 is of a lower octane rating than you think.
Im running 20 on my 14b with zero knock. ## not seeing real knock. Its def phantom knock ## seeing. is there a phantom knock setting you can flick on? You should be able to crank up the timming. 12 is very very low timing for E85

 

[BoostedBeaver]

The knock sensor settings are already at 50% throttle and 4100 RPMs. This timing is at 4k, I run 20 degrees up top where the timing advance is needed to keep up with RPM's. Thanks for the thoughts.

Robert

 

[Calan]

Everything looks identical to the clean log at that RPM point (airflow, AFR, timing, load factor, etc), so I would consider it an anomaly unless you see it again at the same spot. Could have been a minor signal glitch, voltage hiccup, gnat farting on the knock sensor, etc.

BTW - Something like a 1.6s 70-90 time...car is moving pretty nicely.

Hmm I cant view the logs as i don't use link.

FYI - You can download the ECMLink app for free on this page, and view all the logs you want.

 

[BoostedBeaver]

Everything looks identical to the clean log at that RPM point (airflow, AFR, timing, load factor, etc), so I would consider it an anomaly unless you see it again at the same spot. Could have been a minor signal glitch, voltage hiccup, gnat farting on the knock sensor, etc.

BTW - Something like a 1.6s 70-90 time...car is moving pretty nicely.

Thanks for the input Craig, it is greatly valued. I thought this was a glitch to until I got to the house and started picking up knock while free reeving in the drive way. After this, I started to lean towards a loose/bad sensor. I have since tightened the sensor a 1/4 turn or so, so tomorrow we will find out if this is truly knock. Again thanks for the input.

BTW - Thanks for the complement on the 70 - 90 times!!! I am dialing the car back in to 30-32psi and shooting for a 11.5 tomorrow in the 1/4. Just did a lot to the rear end to try and get a better 60' (videos posted in the suspension tech articles).

FWIW these nice AFR's were produced using Linktools 2.4 Thanks again for this program.

Robert

 

[BoostedBeaver]

So the culprit was a gremlin I guess. took the car out yesterday morning and no knock with the same tune. If you see 2* of knock all the sudden, do another cautious pull (after making sure AFR's and boost are as commanded and in a good tuning range) to confirm it is knock. If it is, you will be able to reproduce it.

On another note, if you start going lean all the sudden (this happened yesterday at the track) check your fuse holder for your rewire kit. Mine did not hold the fuse tight and after I used a pair of needle nose pliers to make the fuse holder tighter, it now runs as it is told. Again this is just an FYI as it happened to me yesterday.

Robert