Update (warning long posting):
Still waiting on tuner (On3 Dyno & Performance) to get caught up w\ all previous scheduled work after moving into new shop last month to get me a dyno session setup..... Visited them last week to get a tour of the new digs & tuner showed me his work schedule while there so a slot will be coming open fairly soon (they haven't moved their dyno in yet as they're scheduling to build an extension onto the existing new shop that will be dedicated to only performance-oriented work so dyno work is still having to be done at the old shop).
In the meantime................
Since swapping the IM's out, all was going well until I started noticing an intermittent misfire showing up every now & then about a week after IM swap out....mostly during cold starts but would clear up once engine warmed up so didn't think about it much since was planning to dyno the car (thinking that fueling\MAF scaling may need to be tweaked to match the OEM IM w\ CMDP's as this was tweaked during last dyno session on 4-2-20 w\ the FRPP IM installed). But after thinking about this some more I got out my Foxwell NT301 scan tool & recorded B1S1\B2S1 O2 sensor voltages to see how they're heating up\operating when PCM transitions from OL to CL on the next cold start.....found that both B1S1\B2S1 O2 sensors were VERY slow coming off 0mv so both bank's STFT's were driving very high + numbers (as high as +60% at times) so PCM was loading the fuel to her until the O2 sensors finally responded & voltage drove past 800mv & both bank's STFT's started driving - numbers so PCM started pulling fuel back until the STFT's started switching as they're supposed to (LTFT's had kicked in by then). So during cold starts my engine was getting excessively over fueled for a short period of time (I had the Ford MotorCraft F85F-9G4444-BD O2 sensors installed from 9-24-20 as noted in my post #112, I never thought about checking the O2 sensor voltage for warm up\start up operation from OL to CL...had assumed that all was OK since no DTC's showed up) until the PCM caught up.
So from seeing this result I quickly got the car up in the air & pulled these Ford O2 sensors & reinstalled my NTK setup (22060\22500) then tested these in the same manner....found these suckers heated up very quick during a cold start & voltages were already responding to exhaust before the PCM transitioned from OL to CL so STFT's were immediately following the PCM's cold start fuel enrichment (both bank's STFT's were immediately showing - numbers so PCM was pulling fuel right off the bat in CL until the STFT's started switching from LTFT's kicking in so engine wasn't getting excessively over fueled anymore off cold starts) as it should have. Went back afterwards & looked back over some of my old FORScan datalogs of engine cold starts prior 9-24-20 then post 9-24-20 & realized that the slow O2 sensor warmup pattern started as soon as I had swapped out the O2 sensors back then (pulled NTK's, installed Ford's) so this has been going on for some time since 9-24-20..........
All was fine after swap out back to the NTK's....no more misfiring noted during cold starts.....until last Thursday when I started noticing an intermittent misfire again, this time when under a load between 1500-1800 RPM's then clear out. By Saturday this was getting much worse so today I got out my tools & tore her down to pull the plugs & this is what I found:
These are the MC HFSC-24FP OEM plugs I installed new last year in Feb.........these suckers were being cooked alright! Was highly surprised that the engine was still running w\ plugs in this condition! From inspection this plug damage had to have been happening over an extended time frame so the IM swap done last month didn't have anything to do w\ this BUT the FRPP IM's EVAP port routing may have been an accomplice but not the main player. I believe that the slow O2 sensor warmup\slow O2 sensor response of the Ford F85F-9G444-BD O2 sensors during cold starts was the main player in this plug damage as I can't see\find anything else causing this amount of excessive overheat in the cylinders to burn the plugs this bad & where the FRPP IM's EVAP port placement had some influence: the picture on the left are B1 plugs, picture on the right are B2 plugs. Note that B1 plugs got
far more damage to them vs B2 plugs. Now refer back to post #139's 1st picture of the full hot idle graph of my car w\ the FRPP IM installed B1 STFT, B1 LTFT, B2 STFT, B2 LTFT graph lines (3 thru 6 lines from top) then what I typed concerning the EVAP purge operation....this plug damage clearly was influenced by this issue w\ the FRPP IM's EVAP port design as well (causing extra fuel enrichening thru EVAP along w\ excess unmetered air to drive the overheat even more). Noted the cat temps were getting as high as 1400*F on some cold starts thru the datalogs (once I put the logs back to the dashboard setting so that I could see the cat temp PID data) so the engine CC's were indeed hot during this sequence. ECT's were very normal (196-199) thruout so the Mishimoto HP radiator & GT500 cooling fan was doing it's job removing the extra heat out the engine cylinder heads so no sign of any engine overheating thru the ECT thus no sign of engine knock\pinging (but damage looks to show that some detonation may have been present) & engine shows no signs of any physical internal cylinder damage.
Looks like I got away again in the nick of time from another potential catastrophic situation.....
Pulled out my used set of Champions 9406 Iridium plugs (installed these in 8-19 after experiencing misfires then pulled these due to misfires in 11-19....found out later the issue was bad dielectric grease used, not the plugs), cleaned them up good, checked them over, regapped them back to .040" & put them in. Used some WD-40 in the COP boots when I reinstalled them. Got all back together & fired her up......engine running very smooth & no misfires now. Test drove the car after getting all picked up & all is well....engine pickup is immediate & smooth w\ no misfiring at all now.
Sent my tuner a text w\ pictures of these plugs to inform him of findings so that he knows about this when we get on the dyno..........
Gonna plan on whipping out the laptop to run another cold start datalog w\ FORScan to capture operation w\ good plugs installed. Have ordered a new set of MC HFSC-24FP plugs thru Amazon to have on hand.
Heck of a deal! The stuff we gotta work thru just to have a little mo powa!
If all checks out in the tune during the dyno session I maybe picking up some Brisk XOR12YS plugs (supposed to be 1 step colder than OEM) to provide some insurance against this happening again in the future.