Michael Burbidge
Well Known Member
I just finished my third condition inspection. Before the inspection my engine was running great. On the first flight after the inspection I was about 15 minutes into the flight, at full power, climbing through about 4000 ft. when I got what I can only describe as a misfire. I continued to climb to 7000 ft. and got 3 more misfires, on the way up. I then leveled off, pulled back the power and headed back to the airport. I did not get another misfire.
In the first 15 minutes of the flight I was cruising at about 2500 ft. and probably 50% power. I did not experience a misfire during that portion of the flight nor on takeoff.
I have basic Van's instrumentation, so I do not have recorded flight or engine data. I also did not have the presence of mind to do any diagnostics. I was focused on gaining some altitude and getting back to the airport.
Mag checks on the ground were fine.
Startup and idle were normal.
Here's the basics of my engine:
1 P-Mag, 1 slick mag
O320-D3G
TSMOH @1150 hours
Here's what I did during the condition inspection that could potentially be related:
Ignition related
Replaced auto plugs on the p-mag, gapped
Cleaned aviation plugs on the slick mag, gapped
Removed and checked p-mag, retimed.
Retimed slick mag, it was about 1 1/2 degree off (it was overhauled last condition inspection. I think some drift is normal.)
Slightly re-routed plug wires
Ohm check on auto plug wires
Induction related
Replaced intake pipe gaskets. (two were leaking)
Replaced intake pipe hose and hose clamps.
Cleaned air filter
Cleaned gascolator (no debri found)
Oil related
Removed oil cooler, repaired baffle cracks, replaced oil filter
Rerouted bottom oil cooler line to avoid chaffing
Replaced, rerouted breather tube to avoid new oil cooler line placement
I'm not sure where to start looking for the problem. So far I have rechecked p-mag and mag timing. Replaced the new auto plugs with another set. Looked for signs of intake leaks (blue stains, I'm not sure how long it would take so show up) Rerouted plug wires so that the aviation wires do not cross with the auto wires. (they were touching in one spot) My auto plug wires are separated as described in the installation instructions.
Having done this, my inclination is to go for another flight, staying close to the airport and if the problem persists, I will do a mag check at altitude, turn on the boost pump at altitude to see if the problem goes away.
I would appreciate any other diagnostics suggestions to help me find the problem.
Thank you,
Michael-
In the first 15 minutes of the flight I was cruising at about 2500 ft. and probably 50% power. I did not experience a misfire during that portion of the flight nor on takeoff.
I have basic Van's instrumentation, so I do not have recorded flight or engine data. I also did not have the presence of mind to do any diagnostics. I was focused on gaining some altitude and getting back to the airport.
Mag checks on the ground were fine.
Startup and idle were normal.
Here's the basics of my engine:
1 P-Mag, 1 slick mag
O320-D3G
TSMOH @1150 hours
Here's what I did during the condition inspection that could potentially be related:
Ignition related
Replaced auto plugs on the p-mag, gapped
Cleaned aviation plugs on the slick mag, gapped
Removed and checked p-mag, retimed.
Retimed slick mag, it was about 1 1/2 degree off (it was overhauled last condition inspection. I think some drift is normal.)
Slightly re-routed plug wires
Ohm check on auto plug wires
Induction related
Replaced intake pipe gaskets. (two were leaking)
Replaced intake pipe hose and hose clamps.
Cleaned air filter
Cleaned gascolator (no debri found)
Oil related
Removed oil cooler, repaired baffle cracks, replaced oil filter
Rerouted bottom oil cooler line to avoid chaffing
Replaced, rerouted breather tube to avoid new oil cooler line placement
I'm not sure where to start looking for the problem. So far I have rechecked p-mag and mag timing. Replaced the new auto plugs with another set. Looked for signs of intake leaks (blue stains, I'm not sure how long it would take so show up) Rerouted plug wires so that the aviation wires do not cross with the auto wires. (they were touching in one spot) My auto plug wires are separated as described in the installation instructions.
Having done this, my inclination is to go for another flight, staying close to the airport and if the problem persists, I will do a mag check at altitude, turn on the boost pump at altitude to see if the problem goes away.
I would appreciate any other diagnostics suggestions to help me find the problem.
Thank you,
Michael-