10 Jun 2025, 09:34 [ UTC - 5; DST ]
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Post subject: Re: Engine stumbling C421 Posted: 19 Feb 2016, 11:25 |
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Joined: 01/24/10 Posts: 7359 Post Likes: +5024 Location: Concord , CA (KCCR)
Aircraft: 1967 Baron B55
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Username Protected wrote: Jack are you referring to the right nacelle or locker tank. The 421C does not have aux tanks. Right nacelle.
Is there a filter on the line from the electric pump to the main tank?
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Post subject: Re: Engine stumbling C421 Posted: 19 Feb 2016, 18:54 |
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Joined: 01/09/13 Posts: 1249 Post Likes: +246 Location: Frederick , MD (KHGR)
Aircraft: C421 B36TC 58P
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Username Protected wrote: So are you confident you found the problem They don't see how any fuel was getting through the injectors on the left side. Those lines had a lot of junk in them, worse than the right side for some reason. Yes, they're confident that was the problem. I just can't come up with a good explanation for the source of the random debris, or the timing of it coming through the system.
PFM
_________________ Good Luck,
Tim -------------------
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Post subject: Re: Engine stumbling C421 Posted: 21 Feb 2016, 17:16 |
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Joined: 04/13/15 Posts: 30 Post Likes: +10 Company: Independent contractor Location: Charlotte, NC
Aircraft: PC12NG, Baron G58
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Jack, I saw your similar post on the twincessna.org forum, as well as this forum, so for the benefit of all, I will post this on both. It seems that you are suspecting that foreign debris in one of your fuel tanks was the cause. I had a similar experience in the 414A RAM VII with oil heated fuel manifolds. 204 gal. total/no wing locker tanks installed. At FL 250, the RH engine stumbled, surged, then one cyl showed no EGT. RH engine was firing/running on only 5 cylinders. After landing, both engines ran fine. Mechanic suspected a fuel problem. Filters and injectors were clean, but my pre-flight sumping had previously been getting some trash from the RH wing. The fuel manifold/flow divider was disassembled (it was a RAM overhauled part) and it showed some slight roughness on the poppet shaft, so it was replaced as a precaution. The RH wing was de-fueled and inspected. The A&P (David at Gwinnett Aero at Lawrenceville, GA KLZU) found quite a bit of grit and trash. This was apparently from a previous corrosion repair on an internal tank area. The A&P dried out the RH wing and vacuumed out/cleaned this residue. The problem has not recurred since. The consensus was that trash in the RH wing had blocked the injector to one cylinder. The actual bit of trash that caused the blockage was never found, but so much trash was discovered in the RH wing, that I was confident that the cause was trash in the fuel tank. Eric
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Post subject: Re: Engine stumbling C421 Posted: 22 Feb 2016, 09:25 |
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Joined: 04/13/15 Posts: 30 Post Likes: +10 Company: Independent contractor Location: Charlotte, NC
Aircraft: PC12NG, Baron G58
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Username Protected wrote: Don't the fuel strainers stop trash capable of clogging an injector? They are supposed to, but some of the debris in my wing tank was like medium to fine dust from abrasive grinding wheels. The theory was that it was fine enough, that it passed through the filters. The A&P said that it doesn't take much to block an injector. My wings now sump clear, and the engines are running great since that incident.
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Post subject: Re: Engine stumbling C421 Posted: 22 Feb 2016, 10:36 |
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Joined: 08/20/09 Posts: 2528 Post Likes: +2078 Company: Jcrane, Inc. Location: KVES Greenville, OH
Aircraft: C441, RV7A
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Username Protected wrote: Jack, I saw your similar post on the twincessna.org forum, as well as this forum, so for the benefit of all, I will post this on both. It seems that you are suspecting that foreign debris in one of your fuel tanks was the cause. I had a similar experience in the 414A RAM VII with oil heated fuel manifolds. 204 gal. total/no wing locker tanks installed. At FL 250, the RH engine stumbled, surged, then one cyl showed no EGT. RH engine was firing/running on only 5 cylinders. After landing, both engines ran fine. Mechanic suspected a fuel problem. Filters and injectors were clean, but my pre-flight sumping had previously been getting some trash from the RH wing. The fuel manifold/flow divider was disassembled (it was a RAM overhauled part) and it showed some slight roughness on the poppet shaft, so it was replaced as a precaution. The RH wing was de-fueled and inspected. The A&P (David at Gwinnett Aero at Lawrenceville, GA KLZU) found quite a bit of grit and trash. This was apparently from a previous corrosion repair on an internal tank area. The A&P dried out the RH wing and vacuumed out/cleaned this residue. The problem has not recurred since. The consensus was that trash in the RH wing had blocked the injector to one cylinder. The actual bit of trash that caused the blockage was never found, but so much trash was discovered in the RH wing, that I was confident that the cause was trash in the fuel tank. Eric Thanks Eric, It seems we have the same problem. When they pulled the lines off the nacelle tank, prior to the transfer pump they found quite a bit more debris. They're in the process of flushing the nacelle tank and transfer pump now. We haven't been able to get any more debris out of the main tank. Filters are clean, injectors are clean and fuel is pumping clean at each injector line. Perplexed about the source of the debris.
_________________ Jack N441M N107XX Bubbles Up
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Post subject: Re: Engine stumbling C421 Posted: 22 Feb 2016, 10:53 |
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Joined: 07/11/11 Posts: 2375 Post Likes: +2627 Location: Woodlands TX
Aircraft: C525 D1K Waco PT17
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About 3 years ago, after a string of storms along the Texas, Oklahoma, Louisiana area, I started noticing a lot of crud every time I strained the fuel. I seldom park my airplane on the ramp, and it was very unusual to see this if the airplane spent most of its time inside a hangar when not flying. I never had the engine miss, but had our shop look into it anyway. This is what they found and what they got out after flushing out the fuel system.
Bottom line, I must have picked up fuel somewhere where they were getting water and dirt into their fuel tanks and were selling it like this.
In Jack's case, though, it looks like it was something left over from previous maintenance to the fuel system or wing locker tanks.
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Post subject: Re: Engine stumbling C421 Posted: 26 Feb 2016, 01:53 |
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Joined: 05/11/10 Posts: 9429 Post Likes: +13515 Company: ? Most always. I like people. Location: KFIN Flagler, FL
Aircraft: 1991 Bonanza A36
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Username Protected wrote: I think a lot of junk in our fuel tanks comes right out of the fuel nozzle. At self service islands I have seen guys drop the nozzle on the asphalt and cement, those tips of the nozzle hit. Before I fuel I have made it a habit to let some fuel out of the nozzle before I put into the tank of my plane. I know its not the most environmentally sound practice but its better then in the tanks. I'm too cheap to dump fuel. I just swallow it and blow it into the tank through my nose. OOPS...wrong thread...
_________________ Bible In Poems BibleInPoems.com BNice
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Post subject: Re: Engine stumbling C421 Posted: 26 Feb 2016, 10:31 |
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Joined: 08/20/09 Posts: 2528 Post Likes: +2078 Company: Jcrane, Inc. Location: KVES Greenville, OH
Aircraft: C441, RV7A
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So they cleaned and flushed both tanks, cleaned all filters, flushed all lines. No more debris anywhere. Found and fixed a couple "while you're in there's" which added a few days. Test flew yesterday, no change. Now it won't idle very well either. https://www.savvyanalysis.com/flight/12 ... 1c0716b3fd(pretty sure the #5 egt is a probe or wire problem, it was removed and reinstalled after last flight) RAM wants us to pull the fuel pump, pressure regulator, throttle body, & fuel manifold and ship to their shop for bench testing. I hate to do that because they're just guessing and who knows how long it will take. Somebody else thinks it's an upper deck pressure issue, they're going over those fittings and lines now. Also going to pressurize the induction system, possibly something we overlooked there.
_________________ Jack N441M N107XX Bubbles Up
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Post subject: Re: Engine stumbling C421 Posted: 26 Feb 2016, 14:03 |
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Joined: 01/31/10 Posts: 13479 Post Likes: +7568 Company: 320 Fam
Aircraft: 58TC, E-55, 195
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Username Protected wrote: I feel your pain as a former 421 owner. Those GTSIO's are so complex that we rarely could get 10-15 hrs. without some sort of engine maintenance. I hope you find the culprit soon. Wow. Mine were very reliable.
_________________ Views are my own and don’t represent employers or clients My E55 : https://tinyurl.com/4dvxhwxu
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