Lots of knock past 6000 rpms
Jul 25, 2014, 08:22 AM
#16
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New plugs going in tonight, as well as a seafoam treatment. Also planning on looking the exterior of the engine over really well for any rattles or loose components that may be causing vibration. I'll report back as soon as I do or don't find something out!
Jul 30, 2014, 06:49 PM
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Update:
Installed new OE plugs (gapped properly at 22), made sure there wasn't any oil in the plumbing, seafoamed, changed FPR, checked exterior of block and head for things that could be hitting it and causing fake knock... Nothing. Steth'd the head, no noise. I have done everything short of changing the knock sensor or putting a detonation can on it. The engine sounds amazingly healthy. So, my best guess is that it is transmission or clutch related. Either way I used AccessTuner to reduce the knock sensitivity until the issue went away. I have to say, it is GREAT to feel the car PULL at 6000 rpm instead of fall on its face. I am not 100% satisfied with the "fix", as I would really like to know what the real problem is, but it feels and sounds 100% healthy as is so I guess I will roll with it!
Thank you guys.
Installed new OE plugs (gapped properly at 22), made sure there wasn't any oil in the plumbing, seafoamed, changed FPR, checked exterior of block and head for things that could be hitting it and causing fake knock... Nothing. Steth'd the head, no noise. I have done everything short of changing the knock sensor or putting a detonation can on it. The engine sounds amazingly healthy. So, my best guess is that it is transmission or clutch related. Either way I used AccessTuner to reduce the knock sensitivity until the issue went away. I have to say, it is GREAT to feel the car PULL at 6000 rpm instead of fall on its face. I am not 100% satisfied with the "fix", as I would really like to know what the real problem is, but it feels and sounds 100% healthy as is so I guess I will roll with it!
Thank you guys.
Jul 30, 2014, 08:55 PM
#18
That would make me nervous as hell.
Until I had minimally a wideband to prove it wasn't going lean up top, I wouldn't turn down the knock sensitivity myself.
I'd prefer to also see fuel pressure with a mechanical gauge as well as injector duty cycle from the ECU. Could be a clogged fuel filter, some bad low-octane gas, a crank/cam/mivec sensor issue causing timing to jump past MBT.
Who knows? I agree you think it sounds healthy but it would sound healthy until that exact knock event occurs.... The other parts of the tune could be fine except for just that 6000rpm area. I had a downpipe hitting the frame on my Evo IX... only when under serious G forces I'd see 15* knock. Did I turn down the sensitivity? Nope, I fixed my rattle with a piece of fiberglass exhaust wrap metal-zip-tied to the pipe so it couldn't rattle against the frame.
I know you have your reasons for turning it down.... but damn that's risky. Especially at high RPM. My advice is to fix your noise issue with det cans if you think that its just noise. Also why not log G-Force sensor values to see if you only get knock under some serious G's which indicate a rattle-like issue. Where as rolling into the same load cells with smooth G-forces may not knock..... Stuff like that.
Until I had minimally a wideband to prove it wasn't going lean up top, I wouldn't turn down the knock sensitivity myself.
I'd prefer to also see fuel pressure with a mechanical gauge as well as injector duty cycle from the ECU. Could be a clogged fuel filter, some bad low-octane gas, a crank/cam/mivec sensor issue causing timing to jump past MBT.
Who knows? I agree you think it sounds healthy but it would sound healthy until that exact knock event occurs.... The other parts of the tune could be fine except for just that 6000rpm area. I had a downpipe hitting the frame on my Evo IX... only when under serious G forces I'd see 15* knock. Did I turn down the sensitivity? Nope, I fixed my rattle with a piece of fiberglass exhaust wrap metal-zip-tied to the pipe so it couldn't rattle against the frame.
I know you have your reasons for turning it down.... but damn that's risky. Especially at high RPM. My advice is to fix your noise issue with det cans if you think that its just noise. Also why not log G-Force sensor values to see if you only get knock under some serious G's which indicate a rattle-like issue. Where as rolling into the same load cells with smooth G-forces may not knock..... Stuff like that.
Last edited by acidtonic; Jul 30, 2014 at 08:58 PM.
Jul 31, 2014, 10:13 AM
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That would make me nervous as hell.
Until I had minimally a wideband to prove it wasn't going lean up top, I wouldn't turn down the knock sensitivity myself.
I'd prefer to also see fuel pressure with a mechanical gauge as well as injector duty cycle from the ECU. Could be a clogged fuel filter, some bad low-octane gas, a crank/cam/mivec sensor issue causing timing to jump past MBT.
Who knows? I agree you think it sounds healthy but it would sound healthy until that exact knock event occurs.... The other parts of the tune could be fine except for just that 6000rpm area. I had a downpipe hitting the frame on my Evo IX... only when under serious G forces I'd see 15* knock. Did I turn down the sensitivity? Nope, I fixed my rattle with a piece of fiberglass exhaust wrap metal-zip-tied to the pipe so it couldn't rattle against the frame.
I know you have your reasons for turning it down.... but damn that's risky. Especially at high RPM. My advice is to fix your noise issue with det cans if you think that its just noise. Also why not log G-Force sensor values to see if you only get knock under some serious G's which indicate a rattle-like issue. Where as rolling into the same load cells with smooth G-forces may not knock..... Stuff like that.
Until I had minimally a wideband to prove it wasn't going lean up top, I wouldn't turn down the knock sensitivity myself.
I'd prefer to also see fuel pressure with a mechanical gauge as well as injector duty cycle from the ECU. Could be a clogged fuel filter, some bad low-octane gas, a crank/cam/mivec sensor issue causing timing to jump past MBT.
Who knows? I agree you think it sounds healthy but it would sound healthy until that exact knock event occurs.... The other parts of the tune could be fine except for just that 6000rpm area. I had a downpipe hitting the frame on my Evo IX... only when under serious G forces I'd see 15* knock. Did I turn down the sensitivity? Nope, I fixed my rattle with a piece of fiberglass exhaust wrap metal-zip-tied to the pipe so it couldn't rattle against the frame.
I know you have your reasons for turning it down.... but damn that's risky. Especially at high RPM. My advice is to fix your noise issue with det cans if you think that its just noise. Also why not log G-Force sensor values to see if you only get knock under some serious G's which indicate a rattle-like issue. Where as rolling into the same load cells with smooth G-forces may not knock..... Stuff like that.
I wish it were something as simple as exhaust or something making contact, but I have combed this thing over as fine toothed as I can...
I have kept my senses sharp each time I hit the 6000 mark and don't hear or feel anything unhealthy at all. I'm still a little nervous...
I appreciate the input man.
Last edited by jershelb; Jul 31, 2014 at 10:15 AM.
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