Help.... turbo 5.3 with false knock (or real quiet knock)
09-17-2014, 09:55 AM
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Help.... turbo 5.3 with false knock (or real quiet knock) Need help and or ideas, thanks in advance!! Working on a friends Silverado with a false knock issue or a real knock we cant track down or hear... his setup consist of:
-01 ECSB Silverado
-01 5.3 stock short block (came from known good running donor)
-LS6 oil pump and JP double roller chain
-Speed inc. TU2 cam, TSP dual springs
-shaved 243 heads and LS9 gaskets with ARP bolts
-Trick performance 78mm turbo kit
-full 4wd 4l80e conversion
-maybe good? used (off of here) rev maxx 3600 converter
Its running on a 2 bar SD tune, tuned by us with help from Zippy with Zippy performance, truck is getting knock bad under load (even light load) while in gear from 1500 rpm's on up.... will not show knock in park/neutral at same rpm's ever? Can not hear any noticeable knocking even with stethoscope on any part of engine or trans, normal dual spring clatter, knock sensors are brand new GM torqued to spec with new harness, all wiring from connector to ECM has ohm'ed out just fine, knock sensor pins at ECM have good tension. We have installed another set of sensors and harness with the same result. We did mount a set of grounded sensors off to the side of the engine and test drove with no knock what so ever so ECM if definitely picking something up... nothing is rubbing, everything is tight, fresh tank of 91 octane (already drained and re-filled), TR6 plugs gapped at .035, motor/trans mounts look ok.... Only thought we have is a bad Rev maxx converter making an internal noise under load in gear??? Its kind of all that's left? Any idea's would help greatly, Zippy says its not a tuning issue and I have full faith in him! Thanks again JR
-01 ECSB Silverado
-01 5.3 stock short block (came from known good running donor)
-LS6 oil pump and JP double roller chain
-Speed inc. TU2 cam, TSP dual springs
-shaved 243 heads and LS9 gaskets with ARP bolts
-Trick performance 78mm turbo kit
-full 4wd 4l80e conversion
-maybe good? used (off of here) rev maxx 3600 converter
Its running on a 2 bar SD tune, tuned by us with help from Zippy with Zippy performance, truck is getting knock bad under load (even light load) while in gear from 1500 rpm's on up.... will not show knock in park/neutral at same rpm's ever? Can not hear any noticeable knocking even with stethoscope on any part of engine or trans, normal dual spring clatter, knock sensors are brand new GM torqued to spec with new harness, all wiring from connector to ECM has ohm'ed out just fine, knock sensor pins at ECM have good tension. We have installed another set of sensors and harness with the same result. We did mount a set of grounded sensors off to the side of the engine and test drove with no knock what so ever so ECM if definitely picking something up... nothing is rubbing, everything is tight, fresh tank of 91 octane (already drained and re-filled), TR6 plugs gapped at .035, motor/trans mounts look ok.... Only thought we have is a bad Rev maxx converter making an internal noise under load in gear??? Its kind of all that's left? Any idea's would help greatly, Zippy says its not a tuning issue and I have full faith in him! Thanks again JR
