8092e
Active Member
- Joined
- Nov 6, 2013
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I'm new to the forum so apologies if I should have posted this in a different forum. I've got a 1979 Archer II with a almost new IO-360 ~ 500 hours since previous motor was replaced because of crack (longer story).
Recently I've noticed a random missing issue the type of thing that gives you reason to pause; problem occurs in cruise after some time in normal flight under normal leaning, but under normal PD can't seem to isolate it: Mag checks, fuel boost pump, swapped tanks, changed throttle settings - only higher RPM's seem to address once the problem has occurred. Last instance after plug replacement was 3 hour flight - 2.5 hours normal operations - last leg 1/2 hour started to miss noticeably. Landed pulled plugs and none showed any oil fouling (previous theory).
I broke down and just installed a JPI 730 (less then 3 hours ago) for better diagnostics but we have not been able to catch the issue with a 6 second sample size - just adjusted it down to 2 seconds for better data capture.
So what have we done to date: we've swapped out all plugs with new Tempest plugs (previously had a bad Champion plug based upon bench testing with a meter). We have not done a high voltage load test of wires, both Slick mags rebuilt last year as part of annual. New plugs seem to be operating as expected. We just checked gasolator, fuel pump filter and carb filter all clean as expected (some minor film but nothing material that would impede fuel flow).
I've had all sorts of theories from the guys on the field:
1) seals on primer lines (no apparent discoloration from dye not buying that)
2) potentially random faulty lifter (need to isolate cylinder to do more PD 3) potentially random value issue (500 hour new motor - no obvious issue with plugs - hoping JPI calibrated to 2 sec capture will give me data to show me which one to explore more. Its only a quick flutter of the tach so I feel like I'm chasing gremlins.
4) It was suggested to run a couple hours ROP and see if the problem re-occurs.
5) It was suggested I start the MMO in the fuel system and see if the problem returns.
Frankly I'm not excited to put the family back in the plane until I find a smoking gun.
Any insights are very much appreciated!
John
8092E
KHAO
Recently I've noticed a random missing issue the type of thing that gives you reason to pause; problem occurs in cruise after some time in normal flight under normal leaning, but under normal PD can't seem to isolate it: Mag checks, fuel boost pump, swapped tanks, changed throttle settings - only higher RPM's seem to address once the problem has occurred. Last instance after plug replacement was 3 hour flight - 2.5 hours normal operations - last leg 1/2 hour started to miss noticeably. Landed pulled plugs and none showed any oil fouling (previous theory).
I broke down and just installed a JPI 730 (less then 3 hours ago) for better diagnostics but we have not been able to catch the issue with a 6 second sample size - just adjusted it down to 2 seconds for better data capture.
So what have we done to date: we've swapped out all plugs with new Tempest plugs (previously had a bad Champion plug based upon bench testing with a meter). We have not done a high voltage load test of wires, both Slick mags rebuilt last year as part of annual. New plugs seem to be operating as expected. We just checked gasolator, fuel pump filter and carb filter all clean as expected (some minor film but nothing material that would impede fuel flow).
I've had all sorts of theories from the guys on the field:
1) seals on primer lines (no apparent discoloration from dye not buying that)
2) potentially random faulty lifter (need to isolate cylinder to do more PD 3) potentially random value issue (500 hour new motor - no obvious issue with plugs - hoping JPI calibrated to 2 sec capture will give me data to show me which one to explore more. Its only a quick flutter of the tach so I feel like I'm chasing gremlins.
4) It was suggested to run a couple hours ROP and see if the problem re-occurs.
5) It was suggested I start the MMO in the fuel system and see if the problem returns.
Frankly I'm not excited to put the family back in the plane until I find a smoking gun.
Any insights are very much appreciated!
John
8092E
KHAO
