Dealing with Knock and Hi Boost. Advice needed. Logs attached
May 16, 2019, 01:15 PM
#1
Evolving Member
Thread Starter
Dealing with Knock and Hi Boost. Advice needed. Logs attached
I've noticed that since getting my car back from my tuner over the winter that my CEL flashes sometimes, seemingly at random when doing pulls or at partial throttle/ higher RPM.
I realize that this is a Knock indicator, so now that the weather is nice and I am able to drive more, I have been doing some logging.
I did multiple pulls in 3rd and 4th gear, WOT, and could not really find the culprit. Then I did a pull on the highway while cruising around 4300RPM, and it lit up like a christmas tree.
- During the pull I was running e85.
Checking the log files, I am seeing WAY too much in Knock Sum.
It goes from 0 counts at 4500RPM and 43TPS, to 3/4/5 counts up until 5200RPM, at 99TPS.
Boost is way too high, with MAP showing 30-33 (I'm tuned to about 27/28).
After 5200 knock starts to decrease to 4, 3, 2, 1 then back to 0 around 6500RPM.
Knock voltage during this time ranges from .8-1.5 if that helps.
(Log name "3rd gear pull KNOCK")
I did another pull from 2nd to 3rd gear, and noticed again around 4500RPM - 5200 RPM, 99TPS, there are 0 then 2, then 1 then 0 again counts in Knock sum.
(Log named "2nd-3rd pull")
I did another pull in 3rd gear, and noticed a few counts of "1" from 3500 - 4300 RPM with 99TPS, AFR at 11.2-11.6.
(Log named "3rd gear pull 2 (Slight knock)")
Finally I did another pull in 4th gear, and it looks like knocksum is showing as "2" from 3600 - 4000RPM, then "1" from 4100-4500, where it switches back to 0.
AFR is 12.6 - 11.3 during the 2 counts, then back to 11.3 during the "1" counts.
(Log named "4th gear pull (2 knock)")
I have included a good 4th gear pull with NO knock as well.
(Log named "4th gear pull (No knock)")
My tuner is dead, and so before I go rushing to find someone else, I figured I would try to diagnose this myself. Everyone starts somewhere.
My thoughts are that boost needs to be turned down; I know that adding fuel could also eliminate some of the knock, but AFR seems good during those cells.
Any advice on how to handle this? Ideally I'd like to make the changes myself, and I am willing to research and learn how to fix it, but any help would be much appreciated.
Thanks for any advice.
Mods:
Speed Density
Full turboback exhaust
Tomei 270 Cams
Walbro 255
STM 4" SD intake
Upper and lower IC piping.
Tial Q BOV
EGR delete
I realize that this is a Knock indicator, so now that the weather is nice and I am able to drive more, I have been doing some logging.
I did multiple pulls in 3rd and 4th gear, WOT, and could not really find the culprit. Then I did a pull on the highway while cruising around 4300RPM, and it lit up like a christmas tree.
- During the pull I was running e85.
Checking the log files, I am seeing WAY too much in Knock Sum.
It goes from 0 counts at 4500RPM and 43TPS, to 3/4/5 counts up until 5200RPM, at 99TPS.
Boost is way too high, with MAP showing 30-33 (I'm tuned to about 27/28).
After 5200 knock starts to decrease to 4, 3, 2, 1 then back to 0 around 6500RPM.
Knock voltage during this time ranges from .8-1.5 if that helps.
(Log name "3rd gear pull KNOCK")
I did another pull from 2nd to 3rd gear, and noticed again around 4500RPM - 5200 RPM, 99TPS, there are 0 then 2, then 1 then 0 again counts in Knock sum.
(Log named "2nd-3rd pull")
I did another pull in 3rd gear, and noticed a few counts of "1" from 3500 - 4300 RPM with 99TPS, AFR at 11.2-11.6.
(Log named "3rd gear pull 2 (Slight knock)")
Finally I did another pull in 4th gear, and it looks like knocksum is showing as "2" from 3600 - 4000RPM, then "1" from 4100-4500, where it switches back to 0.
AFR is 12.6 - 11.3 during the 2 counts, then back to 11.3 during the "1" counts.
(Log named "4th gear pull (2 knock)")
I have included a good 4th gear pull with NO knock as well.
(Log named "4th gear pull (No knock)")
My tuner is dead, and so before I go rushing to find someone else, I figured I would try to diagnose this myself. Everyone starts somewhere.
My thoughts are that boost needs to be turned down; I know that adding fuel could also eliminate some of the knock, but AFR seems good during those cells.
Any advice on how to handle this? Ideally I'd like to make the changes myself, and I am willing to research and learn how to fix it, but any help would be much appreciated.
Thanks for any advice.
Mods:
Speed Density
Full turboback exhaust
Tomei 270 Cams
Walbro 255
STM 4" SD intake
Upper and lower IC piping.
Tial Q BOV
EGR delete
