Wasted Potential Posted November 26, 2017 Author Share Posted November 26, 2017 Uploaded stage 1 ACN91 Tune, put in 93 Fuel. Tank had maybe 3 gallons of 87. Therefore mixture was above 91 octane on average. DAM improved greatly. Did not drop below 0.75, was 0.5 after reflash and went to 1.000 after short drive. Fine knock learn peaked at -7.5 randomly under low RPM and high demand randomly. Log 1: Most variables look good, Feedback Knock was not so great but not horrible. WOT, and a deceleration. Log 2: Bad Feedback Knock. Log 3: BAD Fine knock learn, this was under NO WOT, bad fine knock happened during low rpm (below 2900rpm). would happen under decel. (minimal throttle position) just as bad as when accelerating. Boost seems to be good (maybe no leak?) I peaked at 15.5-16.5 PSI, which I believe is within +/- 1 for the tune goals. I will, however, check for boost leaks when I get it back into the garage. Getting slammed with school load. I need to understand difference between feedback knock versus fine knock learn - I will read up more. Performance has improved surprisingly well when moving to the ACN 91 (mainly due to octane boost I believe). If any other suggestions, feel free to let me know otherwise I will wait for the boost leak check. By the time it gets into the garage I should have my downpipe and up pipe so it may be due for the stage 2 upgrade at the same time. EDIT: I believe I will be looking into Dave @ Cryo, and Mike at tuning alliance shortly to pay for the tune and see if they are willing to help diagnose some issues. I understand if they decline to want to spend the time on the diagnose issue as that seems like a never ending rabitt hole.Mild FBK - WOT and Decel..csvExcessive FBK - WOT and Decel..csvBad FKL - Variable Accel and Load.csv Link to comment Share on other sites More sharing options...
WahooNo2 Posted November 26, 2017 Share Posted November 26, 2017 When was the last time you changed your spark plugs and cleaned your maf? Check that vac lines are tight for the fuel pressure regulator, blow off valve, and intake manifold. Link to comment Share on other sites More sharing options...
Wasted Potential Posted November 26, 2017 Author Share Posted November 26, 2017 Changed spark plugs when I did the compression check, under 1.5k miles ago. I am looking at buying a little smoke tester... it seems I could use it a lot. Just plug it into any port in the intake and be under 5 psi? Link to comment Share on other sites More sharing options...
Max Capacity Posted November 26, 2017 Share Posted November 26, 2017 Yes, that should work to find any leaks in the system. 5psi should not blow any lines off. We do zip tie all the lines we can see, even some we can't. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
baconbits Posted November 26, 2017 Share Posted November 26, 2017 Uh, wouldn't the ~89 octane gas in the tank explain the knock? Switch to the 91ACN because that's like 70 octane (hyperbole) and run it empty so you can fill the tank with 91-93 and then see if it keeps knocking. I'd bet it's the gas. A GT should never get anything less than 91 regardless of tune. Link to comment Share on other sites More sharing options...
Wasted Potential Posted November 26, 2017 Author Share Posted November 26, 2017 I normally put in 91, unfortunately before the flash I was not the last one to drive/fill it. Did not find out until I mentioned gas to the fiancee... Even after I filled with 93, it seems that the feedback knock and fine knock learn still had very bad peaks... mostly under decel it seems. Link to comment Share on other sites More sharing options...
baconbits Posted November 26, 2017 Share Posted November 26, 2017 I would look for loose heatshields on the underside or anything loose like acorns or a forgotten tool or bolt near the knock sensor, middle of the engine, under the intercooler. And the gas. I'd do all that before fearing a burnt valve or the worst unless you have a borescope and can look somehow Link to comment Share on other sites More sharing options...
Wasted Potential Posted November 27, 2017 Author Share Posted November 27, 2017 Dumb question, but it seems there may be some exhausts that vibrate just right to imitate phantom knock connecting manifold to head wise, or downpipe to turbo and vibrating just right. Maybe I found the deadly combo haha. I will look into this vacuum leak, boost leak, and loose components over the week. Schooling coming to a close, busy as can be. It seems most people are not overly worried by the peaks under decal. as they are obviously not as detrimental as knock under load and boost. Link to comment Share on other sites More sharing options...
Wasted Potential Posted November 28, 2017 Author Share Posted November 28, 2017 Accessport on Stage 1 ACN91 stated I hit 17.16 PSI... Should be 14.0 or 14.5 +/-0.8. I need to get it on a log to see if it is merely a spike at certain rpm, or actually holding and maintaining. Any opinions on accuracy of Cobb Accessport for AFR (not in boost) and boost actual? If the ECU does see this 17.x PSI, does it compensate (and how?), and actually run adequately, or does it begin to run immediately lean over the 15/16PSI range if the tune is not meant to see such a high value? Link to comment Share on other sites More sharing options...
Wasted Potential Posted November 29, 2017 Author Share Posted November 29, 2017 Maintaining all logs in one spot - I notice an issue with boost error vs. actual. Does seem the 17.XX psi is a over boost that occurs and then tapers down to ~14psi (where I should be for the tune). I will perform a boost leak test later this week before installing the cobb DP, and STi UP.WOT - Boost Peak and error.csv Link to comment Share on other sites More sharing options...
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