Dieselsnplanes Posted October 31, 2021 Report Share Posted October 31, 2021 (edited) Searched for an hour and came up with nothing related to what I had happened today. I left FHB to head to ATL and got to 7k, leaned engine to 100 ROP. Cylinder 3 is always my hottest but noticed it kept flicking between 1450-1405*. ATC pushed me to 8k, rolled the mixture in and added MP to climb. Once at 8k I reduced the MP back to cruise and started to find peak to reset. This time I couldn’t get EGT to come back down. No change in engine running resulted. No rough running no issues. Tried boost pump, came down for a second and went back up I believe(heavy load in IMC and gave me a STAR to follow during this). Finally pushed the mixture to full rich and the remaining cylinders came down to 1250*. 3 stayed at 1500. Added power to expedite the approach and it came down a little. Remained this way for the remainder of the flight, about 45 min Engine ran fine other than noticing the high EGT on 3. The whole system has 12hrs on it and has worked perfect every flight. Even the 2hr flight from Southwest Florida to FHB. below are the pictures I snapped @ 6K, full rich 24/2500rpm Edited October 31, 2021 by Dieselsnplanes Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted October 31, 2021 Report Share Posted October 31, 2021 That usually means you have a fouled plug. Did you do a mag check? 2 Quote Link to comment Share on other sites More sharing options...
Dieselsnplanes Posted October 31, 2021 Author Report Share Posted October 31, 2021 7 minutes ago, N201MKTurbo said: That usually means you have a fouled plug. Did you do a mag check? No, still new to running tests during flight ops and diag on aircraft engines. I own a diesel repair business but the old technology on these is just a different learning curve. Quote Link to comment Share on other sites More sharing options...
Ragsf15e Posted October 31, 2021 Report Share Posted October 31, 2021 3 minutes ago, Dieselsnplanes said: No, still new to running tests during flight ops and diag on aircraft engines. I own a diesel repair business but the old technology on these is just a different learning curve. Mag check quickly tell you if it’s a plug. Are you leaning really aggressively on the ground after start and after landing? It should basically be on the verge of stumbling during ground ops. If it’s not a plug, other options are an intake leak (although usually not noticeable at full power) or a clogged injector. Both of those can give you a leaner mixture in that cylinder. Most likely it’s the plug. Mag check on the ground, watch the egt closely l/r/b. 1 Quote Link to comment Share on other sites More sharing options...
Dieselsnplanes Posted October 31, 2021 Author Report Share Posted October 31, 2021 3 minutes ago, Ragsf15e said: Mag check quickly tell you if it’s a plug. Are you leaning really aggressively on the ground after start and after landing? It should basically be on the verge of stumbling during ground ops. If it’s not a plug, other options are an intake leak (although usually not noticeable at full power) or a clogged injector. Both of those can give you a leaner mixture in that cylinder. Most likely it’s the plug. Mag check on the ground, watch the egt closely l/r/b. I do try and lean aggressively, I’ve had a clogged injector on cylinder 1 before and it shook the plane and popped really bad out of the exhaust from a hugely lean condition. I was worried about that but the running didn’t change while in the air and I ran it to full power after landing with no issues. I will do a mag check tomorrow, just no AP here till Monday Quote Link to comment Share on other sites More sharing options...
Janat83 Posted October 31, 2021 Report Share Posted October 31, 2021 You mentioned you were flying ifr, did you stayed on ground for long before ifr release?, I used to get similar issues when I stay longer than 10 min waiting for IFR release. I see that your No.3 CHT is showing normal read out like other cylinders, which means it's making good power, usually when a spark plug is fouled the CHT gets lower than other cylinders, it's worth it to do the mag check and see if you have any fouled spark plug, if no spark plug/ ignition issues I'd switch the EGT sensors to eliminate that option and borescope cylinder no. 3 for exhaust leak, if you can share the data of that flight and the previous flight that will help experts here to tell what night be the issue. Quote Link to comment Share on other sites More sharing options...
ArtVandelay Posted October 31, 2021 Report Share Posted October 31, 2021 I think a partially plugged fuel injector would do it too. 1 Quote Link to comment Share on other sites More sharing options...
Dieselsnplanes Posted October 31, 2021 Author Report Share Posted October 31, 2021 8 hours ago, Janat83 said: You mentioned you were flying ifr, did you stayed on ground for long before ifr release?, I used to get similar issues when I stay longer than 10 min waiting for IFR release. I see that your No.3 CHT is showing normal read out like other cylinders, which means it's making good power, usually when a spark plug is fouled the CHT gets lower than other cylinders, it's worth it to do the mag check and see if you have any fouled spark plug, if no spark plug/ ignition issues I'd switch the EGT sensors to eliminate that option and borescope cylinder no. 3 for exhaust leak, if you can share the data of that flight and the previous flight that will help experts here to tell what night be the issue. I called for clearance while taxiing, got it got released immediately, did a run up and left. I actually had to wait on the ground at the hanger for the engine to warm up a bit, leaned aggressively. I’ll see if I can pull the data from the Garmin EIS, my AP suggested an intake leak. I’m going to check it today. I can pull the injector and check it too but I don’t have a spark plug socket and I don’t think tool stores carry them around here. The problem started after I went rich for the climb and then tried to lean again so carbon could be the issue. Just figured if it was that it should burn off in flight. 1 Quote Link to comment Share on other sites More sharing options...
Dieselsnplanes Posted October 31, 2021 Author Report Share Posted October 31, 2021 I think it’s a loose connection on the EGT probe. Checked it this morning and had a red ❌ on cylinder 3, wiggled the wires and it came back to OAT. Intake gaskets seem to be ok, no bluing from fuel and the probes in place Quote Link to comment Share on other sites More sharing options...
DXB Posted October 31, 2021 Report Share Posted October 31, 2021 (edited) Increased EGT on a single cylinder plus: - reduced CHT => fouled plug? - increased CHT => partly clogged injector? induction leak? - nothing else changes => possibly the probe Edited October 31, 2021 by DXB 2 Quote Link to comment Share on other sites More sharing options...
Yetti Posted October 31, 2021 Report Share Posted October 31, 2021 why do you have stainless clamps and water drops on your updraft intake tubes? Quote Link to comment Share on other sites More sharing options...
A64Pilot Posted October 31, 2021 Report Share Posted October 31, 2021 11 hours ago, ArtVandelay said: I think a partially plugged fuel injector would do it too. What I was thinking too Quote Link to comment Share on other sites More sharing options...
1001001 Posted October 31, 2021 Report Share Posted October 31, 2021 (edited) 16 minutes ago, A64Pilot said: What I was thinking too Yes. If the engine was being operated rich of peak, a partial blockage on that injector would cause the cylinder to go lean, and the EGT would rise, as long as the blockage wasn't so severe as to take the cylinder extremely lean. I just recently experienced this, although I was operating the engine lean of peak, so when the blockage occurred, the cylinder was starved for fuel and I experienced significant engine roughness. Thanks to Our Friends at Savvy for looking at this for me and for helping explain it to me and help me better understand the event. One thing you should see when an injector clogs is that the fuel flow will remain constant, but the EGT on the blocked cylinder will change (down, if you were LOP prior to the clog, and up, if you were ROP prior to the clog) and the other cylinders will likely change as well (in the opposite direction) as the fuel from the clogged injector is redistributed to the others. Edited October 31, 2021 by 1001001 typo correction Quote Link to comment Share on other sites More sharing options...
bmcconnaha Posted October 31, 2021 Report Share Posted October 31, 2021 This is where having your data uploaded and being able to do an analysis of both this event, and past flights is great. CHT normally goes down for a fouled plug. Is #3 normally the warmest? On the ground at idle, an induction leak will show itself with higher than usual manifold pressure? CHT can rise or fall with an induction leak depending of if the cylinder is still ROP or now went LOP. Same for a fuel injector partial blockage. Interesting note on the EGT probe. You could ensure connection integrity, and then fly it assuming the mag check shows no fouled plugs and MP is correct at idle. If it still shows high, swap the probe and see if follows the probe. Quote Link to comment Share on other sites More sharing options...
A64Pilot Posted November 1, 2021 Report Share Posted November 1, 2021 First time I had an injector clog (C-210, IO-520) I went slobbering rich, boost on etc in an attempt to control EGT of that cylinder. Later I learned it’s better to just let it go lean, and if that cylinder dies, let it die, that’s not going to hurt it. Quote Link to comment Share on other sites More sharing options...
carusoam Posted November 1, 2021 Report Share Posted November 1, 2021 Let’s say we have a single high EGT event occur… Lets follow the MS engine monitor logic… 1) First thing we want to do is determine how real the situation is…. Is it a hot EGT, or is something causing the monitor to fib… 2) Does the CHT corroborate the high EGT data? (Why no CHT info shared?) 3) if the CHT didn’t change at all… the EGT change probably is an instrument issue… 4) if CHT dropped… a spark plug probably went inop… 5) if CHT rose… a fuel injector probably is partially clogged… 6) an inflight mag check will show plug health… 7) a basic Gami spread test will indicate if the FI has been partially blocked… 8) if EGT stays high… with all plugs OK, and Gami spread staying close… the sensor is highly suspect… 9) plugs fail in two ways… increased resistance/missing center electrode, or they get coated by lead, oil, or carbon… 10) If you lean aggressively on the ground, lead build up is most often eliminated from the equation… Somebody should program this logic into an engine monitor… PP thoughts only, not a mechanic… Engine monitor logic discussed daily on MS… Engine monitors haven’t improved their monitoring skills in 25yrs…. Savvy’s role in engine diagnostics will live for a few more years/decades at this rate… Compare that to an Apple Watch that can tell when their wearer is having an afib challenge… Best regards, -a- 1 Quote Link to comment Share on other sites More sharing options...
Dieselsnplanes Posted November 1, 2021 Author Report Share Posted November 1, 2021 On 10/31/2021 at 12:59 PM, Yetti said: why do you have stainless clamps and water drops on your updraft intake tubes? It was wet in Atlanta, it’s from taking the cowling off. The clamps block off the hole for the old vacuum standby port. Quote Link to comment Share on other sites More sharing options...
Dieselsnplanes Posted November 1, 2021 Author Report Share Posted November 1, 2021 I did a mag check on the ground and it ran perfect, no EGT drop, all rise. Home was mostly IMC so didn’t think doing a mag check was wise to do so. The gauge worked well for most of the trip, flickered a few times so I’m at the belief it’s a loose connection between the probe leads and the wiring to the panel. #3 is my hottest cylinder so it was tough to lean. I just used my fuel flow and also set cylinder 1 to where it normally is compared to cylinder 3. The rapid change in EGT during flight, 30-50* flickering has me relaxed it is mostly just the probe connection. I’m going to check it tonight after work and report back. The 3hr ride home was fine other than the plane hiccuping on water from the line guy filling the tanks and not clearing the water off the caps. Tried to sump as much as I could but ended up sucking it up a few times. Quote Link to comment Share on other sites More sharing options...
jaylw314 Posted November 1, 2021 Report Share Posted November 1, 2021 2 minutes ago, Dieselsnplanes said: I did a mag check on the ground and it ran perfect, no EGT drop, all rise. Home was mostly IMC so didn’t think doing a mag check was wise to do so. The gauge worked well for most of the trip, flickered a few times so I’m at the belief it’s a loose connection between the probe leads and the wiring to the panel. #3 is my hottest cylinder so it was tough to lean. I just used my fuel flow and also set cylinder 1 to where it normally is compared to cylinder 3. The rapid change in EGT during flight, 30-50* flickering has me relaxed it is mostly just the probe connection. I’m going to check it tonight after work and report back. The 3hr ride home was fine other than the plane hiccuping on water from the line guy filling the tanks and not clearing the water off the caps. Tried to sump as much as I could but ended up sucking it up a few times. I've accidentally dumped the water that collects on the fuel caps into the tank a couple times. I've never been able to sump any out, even after shaking the wing and sumping like crazy. AFAIK, water can mix in gasoline -- not much, but to the tune of a couple tablespoons per tank. If your #3 CHT didn't change (we haven't seen before/after values), I'd agree the loose EGT probe is most likely, but it bothers me that it is going high. I thought when EGT probes fail or disconnect they go to zero? Quote Link to comment Share on other sites More sharing options...
1001001 Posted November 1, 2021 Report Share Posted November 1, 2021 Another cause could be a leaking fuel line on that cylinder. The line could be cracked/broken or maybe the fitting could be loose. ask me how I know... Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted November 1, 2021 Report Share Posted November 1, 2021 22 minutes ago, Dieselsnplanes said: I did a mag check on the ground and it ran perfect, no EGT drop, all rise. Home was mostly IMC so didn’t think doing a mag check was wise to do so. The gauge worked well for most of the trip, flickered a few times so I’m at the belief it’s a loose connection between the probe leads and the wiring to the panel. #3 is my hottest cylinder so it was tough to lean. I just used my fuel flow and also set cylinder 1 to where it normally is compared to cylinder 3. The rapid change in EGT during flight, 30-50* flickering has me relaxed it is mostly just the probe connection. I’m going to check it tonight after work and report back. The 3hr ride home was fine other than the plane hiccuping on water from the line guy filling the tanks and not clearing the water off the caps. Tried to sump as much as I could but ended up sucking it up a few times. If it is a thermocouple problem, it is unlikely that it is opening, that would cause it to go to zero and can be detected as a fault by some systems. It may be grounding the TC. Some are meant to be grounded and some are not. I'm not sure what your system requires. That would be a faulty probe either way, unless there is a short to ground somewhere in the wiring. 2 Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted November 1, 2021 Report Share Posted November 1, 2021 On 10/31/2021 at 7:43 AM, Dieselsnplanes said: I think it’s a loose connection on the EGT probe. Checked it this morning and had a red ❌ on cylinder 3, wiggled the wires and it came back to OAT. Intake gaskets seem to be ok, no bluing from fuel and the probes in place In most installations, the top probe is the factory EGT probe and the bottom one is for the scanner. Your bottom one doesn't seem to have any wires coming out of it. Is the top one for the Garmin and the bottom one is just a plug for a previous installation? Quote Link to comment Share on other sites More sharing options...
Yetti Posted November 1, 2021 Report Share Posted November 1, 2021 1 hour ago, Dieselsnplanes said: It was wet in Atlanta, it’s from taking the cowling off. The clamps block off the hole for the old vacuum standby port. Smoke test your intake tubes. Quote Link to comment Share on other sites More sharing options...
Ragsf15e Posted November 2, 2021 Report Share Posted November 2, 2021 9 hours ago, Dieselsnplanes said: I did a mag check on the ground and it ran perfect, no EGT drop, all rise. Home was mostly IMC so didn’t think doing a mag check was wise to do so. The gauge worked well for most of the trip, flickered a few times so I’m at the belief it’s a loose connection between the probe leads and the wiring to the panel. #3 is my hottest cylinder so it was tough to lean. I just used my fuel flow and also set cylinder 1 to where it normally is compared to cylinder 3. The rapid change in EGT during flight, 30-50* flickering has me relaxed it is mostly just the probe connection. I’m going to check it tonight after work and report back. The 3hr ride home was fine other than the plane hiccuping on water from the line guy filling the tanks and not clearing the water off the caps. Tried to sump as much as I could but ended up sucking it up a few times. Just keep an eye on it, because a bad plug will cause an egt rise during a mag check right up until it fails to fire at all. A weak plug doesn’t ignite the fuel as well, so it’s still burning down the exhaust, thus hot egts. When the plug finally fails completely, egt gets colder. Its not perfect, but watch your egts during a mag check. Normalize mode helps on your eis. When you switch to a single mag, you should see a similar total rise on each cylinder. Total temp is likely different, but amount of rise should look about the same for one mag. Between the two mags you might see a small difference if the timing isn’t exactly the same. Quote Link to comment Share on other sites More sharing options...
carusoam Posted November 2, 2021 Report Share Posted November 2, 2021 11 hours ago, Dieselsnplanes said: I did a mag check on the ground and it ran perfect, no EGT drop, all rise. Home was mostly IMC so didn’t think doing a mag check was wise to do so. The gauge worked well for most of the trip, flickered a few times so I’m at the belief it’s a loose connection between the probe leads and the wiring to the panel. #3 is my hottest cylinder so it was tough to lean. I just used my fuel flow and also set cylinder 1 to where it normally is compared to cylinder 3. The rapid change in EGT during flight, 30-50* flickering has me relaxed it is mostly just the probe connection. I’m going to check it tonight after work and report back. The 3hr ride home was fine other than the plane hiccuping on water from the line guy filling the tanks and not clearing the water off the caps. Tried to sump as much as I could but ended up sucking it up a few times. Try to get a feel for how much water is in the tank after it stops coming out of the sump… Expect there to be a lot more than you think…. There is a volume that is lower than the sump… and lower than the pick-up… If your pick-up is getting water to it… consider using a method to remove the excess water… There are dry-gas discussions around here that may be helpful… That volume may be 1/2 a cup or so…. Turbulence might make it continue to show up… My M20C lived outside… I learned a lot about Mooney tanks and water and corrosion…. PP thoughts only, not a mechanic… Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.