XXX Posted July 16, 2017 Author Report Share Posted July 16, 2017 4 hours ago, Jim F said: So it sounds like your engine slowly went rich. No roughness and when you rich end the mixture it got rough. Your FF indicated normal. You say you have a steam gauge and then the fuel flow is really a pressure gauge from the flow divider and marked in GPM. Information needed: is the mixture arm on the Bendix fuel servo hitting its stops? Is the air filter clear? I don't think this is it but checking is easy check the mags to see if they are tight. N201MKTurbo recommended and again it's easy run up, at 2000RPM what is the EGT,FF? Lean to peak, what is the EGT,FF? Boost pump on, what happens? Caution the engine might die because it went to rich. The fuel servo should compensate for the increase incoming fuel pressure. i am thinking that you fuel servo went rich. The servo has two diaframs one has incoming fuel( from fuel pump) and out going fuel ( to the flow divider) A leak in that diafram would make you go rich. Now that said I think this senerio would make your FF increase. The other diafram sees incoming air(before the throttle plate) and MP On the engine monitor: With our engines there is a lot going on and information is critical to keep us safe and the first part of troubleshooting. I am to the point that I think twice before flying without an engine monitor. Jim F Jim, This sounds right on (fuel servo). The mixture is hitting the stops both ways. Air filter clean (replaced a month ago). Having thought about it this morning, I was going to take off my air filter and check the intake for blockage potentially from the cowl to engine accordion duct disintegrating. Your suggestion is more plausible though. I have an appointment with the mechanic tomorrow. I'll keep you posted. Many Thanks, Steve 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted July 16, 2017 Report Share Posted July 16, 2017 +1 for going too Rich in the climb... How high did you climb for this to become noticeable? Follow-up question: Did the Richness challenge go away at lower altitudes? A common practice for leaning in the climb is to keep the EGT in a range from 200°F to 300°F ROP. Readjusting mixture as it falls out the bottom of the range as an NA MP decreases with altitude... This maintains CHTs in a controlled fashion. It also lowers EGT as it goes further ROP... Going beyond a usable mixture will start to generate skips of some plugs at first. This may be perceived as engine roughness... Not leaning properly for the climb, will leave the engine running too rich. for engine out procedures... Sweeping the mixture control from, all the way in, to nearly all the way out, and back in will operate the control through it's full extent. In an emergency, this is done to hopefully find a spot that works... and possibly find the spot it works best... Rereading JimF's ideas above.. Check your logs for the fuel divider's health info. Has it been OH'd ever, and when? Can you supply some more info on your FF instrument. I have not seen a mechanical FF gauge in many Mooneys. Got a picture or a model number? Often a mechanical fuel gauge is a pressure sensor reading the pressure drop across a known flow geometry. There is only one flow rate that can be associated with each pressure drop measured. (Unless there are changes in temperature, density, or viscosity) the panel gauge senses pressure drop and the display is then calibrated in gph... So restating MS best guess... (sort of) 1) Engine is behaving as if it is set too rich... 2) Engine is behaving like it is going too rich during the climb... (normal NA engines do this on their own) 3) Could be a flow divider compensation adjustment or wear issue. 4) trouble shooting gets easier with CHTs and EGTs for all cylinders. 5) FF data is always beneficial to the pilot and mechanic... 6) if the problem went away after a descent... would give some insight... 7) if the problem went away upon leaning the mixture... would give some insight... 8) leaning on the ground and comparing to FF... would give some insight... (My IO550, upon start uses 4 gph, after leaning uses 2gph) normal behavior... (An IO360, may be more like 3 gph, and 1.5gph 9) Exploring every avenue... Going too lean would also show lower CHTs... Going too lean would also show lower EGTs... Going too lean would also suffer plug skipping... climbing doesn't cause going too lean. Fuel dividers are probably designed to fail going to rich. Nice job collecting data to share with your mechanic... Thanks for sharing the details. Best regards, -a- Quote Link to comment Share on other sites More sharing options...
XXX Posted July 18, 2017 Author Report Share Posted July 18, 2017 N6988V is back home! Thanks to all who replied with suggestions and ideas. What a tremendous resource Mooneyspace is! So, after checking induction, fuel servo thumb spring, mixture cable range of motion, intake runner bolt tightness, mags tightness and calling airport where I last fueled to see if they had any reports of contamination, I ended up taking it to maintanance on the field and having injectors pulled and cleaned and compressions checked. No apparent blockage of the injectors but cleaned anyway and compressions of 79x3 and 78. Recowled, did run up and departed for home. Engine ran normally and even had my buddy return me to Jacksonville to retrieve my car, so 3 flights no problems. I'm not convinced it was the injectors but who knows. I am convinced that I want a JPI now. Being stuck out of town sucks but having your fellow Mooniacs hold your hand throughout the ordeal is a real blessing. Thanks again, Steve 4 Quote Link to comment Share on other sites More sharing options...
201er Posted July 18, 2017 Report Share Posted July 18, 2017 If your mags have a lot of time on them, I'd get one of them overhauled/inspected just to be sure. Quote Link to comment Share on other sites More sharing options...
carusoam Posted July 18, 2017 Report Share Posted July 18, 2017 When living the CB pilot lifestyle.... It may help to find a used engine monitor... One of our MSers makes a market in this kind of thing... https://mooneyspace.com/profile/12412-aerodon/ Some engine anomalies are present long before they become obvious. For that, we have another MSer that reads the graphs like he's is reading a work-order for maintenance. Best regards, -a- 2 Quote Link to comment Share on other sites More sharing options...
Bartman Posted July 18, 2017 Report Share Posted July 18, 2017 Good to see a happy ending and didn't take very long either. If you had an engine monitor you could tell the mechanic what is wrong, rather than him telling you what he thinks. I did exactly that once when I had a partially clogged injector. I knew which cylinder and it only took about an hour for him to clean that one, and I was back on my way to Florida after a quick test flight. 1 Quote Link to comment Share on other sites More sharing options...
XXX Posted July 18, 2017 Author Report Share Posted July 18, 2017 4 minutes ago, 201er said: If your mags have a lot of time on them, I'd get one of them overhauled/inspected just to be sure. Mike, Both mags were rebuilt around 225 hours ago. Quote Link to comment Share on other sites More sharing options...
neilpilot Posted July 18, 2017 Report Share Posted July 18, 2017 3 minutes ago, Bartman said: Good to see a happy ending and didn't take very long either. If you had an engine monitor you could tell the mechanic what is wrong, rather than him telling you what he thinks. I did exactly that once when I had a partially clogged injector. I knew which cylinder and it only took about an hour for him to clean that one, and I was back on my way to Florida after a quick test flight. While this is often true, it isn't always the case. I fought a similar issue with the IO360A1A for about 2 years. It was intermittent, and after various attempts to eliminate the issue (including mag rebuilds, and about 6 months later bench check and service to fuel injection controller) I totaled my Mooney in an off field landing. It seems a piece of a torn o-ring in the fuel controller might have been floating around for some time. The problem would only manifest itself occasionally, and most of the time the fuel servo would perform well and even pass bench testing. It was not discovered when the fuel system was serviced, and eventually resulted in an off-field forced landing many months later. S"tuff" happens. 1 Quote Link to comment Share on other sites More sharing options...
DonMuncy Posted July 18, 2017 Report Share Posted July 18, 2017 7 minutes ago, Bartman said: If you had an engine monitor you could tell the mechanic what is wrong, rather than him telling you what he thinks. I did exactly that once when I had a partially clogged injector. I knew which cylinder and it only took about an hour for him to clean that one, and I was back on my way to Florida after a quick test flight. I had the exact same thing. Engine got rough, within about 30 minutes of takeoff. I went through the process and came to the conclusion it did not require a precautionary landing. By the time I got to my destination, I had diagnosed a partially clogged injector. Told the mechanic to check the number x injector. Thirty minutes later, he had pulled and blew it out. Problem solved. Nice to not only save a bunch of A&P charges, but really feeds the ego. 3 Quote Link to comment Share on other sites More sharing options...
Yetti Posted July 18, 2017 Report Share Posted July 18, 2017 I was thinking did they do the fuel flow 4 mason jar test when the injectors were out. 1 Quote Link to comment Share on other sites More sharing options...
XXX Posted July 18, 2017 Author Report Share Posted July 18, 2017 1 minute ago, neilpilot said: While this is often true, it isn't always the case. I fought a similar issue with the IO360A1A for about 2 years. It was intermittent, and after various attempts to eliminate the issue (including mag rebuilds, and about 6 months later bench check and service to fuel injection controller) I totaled my Mooney in an off field landing. It seems a piece of a torn o-ring in the fuel controller might have been floating around for some time. The problem would only manifest itself occasionally, and most of the time the fuel servo would perform well and even pass bench testing. It was not discovered when the fuel system was serviced, and eventually resulted in an off-field forced landing many months later. S"tuff" happens. Neilpilot, not gonna hit the like button for that story. Glad you're ok and sure hope this doesn't become an intermittent issue with mine. Quote Link to comment Share on other sites More sharing options...
XXX Posted July 18, 2017 Author Report Share Posted July 18, 2017 Just now, Yetti said: I was thinking did they do the fuel flow 4 mason jar test when the injectors were out. No they did not. I've not heard of the fuel flow 4 (sounds like an arrival procdure) mason jar test. Please elaborate. Quote Link to comment Share on other sites More sharing options...
Yetti Posted July 18, 2017 Report Share Posted July 18, 2017 Take 4 of the Jelly mason jars. Put injector lines into each one. Crank for a couple revolutions. All Jars should have the same amount of fuel. Burnable high octane gas cautions apply 1 Quote Link to comment Share on other sites More sharing options...
XXX Posted July 18, 2017 Author Report Share Posted July 18, 2017 Just now, Yetti said: Take 4 of the Jelly mason jars. Put injector lines into each one. Crank for a couple revolutions. All Jars should have the same amount of fuel. Burnable high octane gas cautions apply Gotcha. If the amounts are different, does it point to a fuel servo issue? Quote Link to comment Share on other sites More sharing options...
Raptor05121 Posted July 18, 2017 Report Share Posted July 18, 2017 I just read about that test (check out Light Plane Maintenance library, good books, I can loan them if you'd like). I believe one odd duck would be an injector issue, but I'm not qualified to say so. 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted July 18, 2017 Report Share Posted July 18, 2017 Doing a search, it may be called the baby food jar test... It is a test to see if a fuel injector is blocked, including the lines up to the FI. Each injector is put in a glass jar, the fuel pump is run, for a set time. The output of each injector is observed and measured. It is a good test when trying to demonstrate they are all clean and delivering the same amount. It has got to be comforting when you have cleaned them all and things are runnng smoothly. But, without finding the smoking gun, you may want to maintain your super Mooney pilot vigilance... Some Mooney fuel lines close to the fuel injectors are rubber, or have a rubber lining that has been known to sluff off small rubber bits. You may want to find if you have this particular hose and when it has been changed last... PP thoughts only, not a mechanic... Best regards, -a- 2 Quote Link to comment Share on other sites More sharing options...
Yetti Posted July 18, 2017 Report Share Posted July 18, 2017 More of a fuel divider /injector line test. We did it without the Injectors. Injectors were soaked in Hoppes #9 to clear the lead fouling. Might as well clean the finger screen on the fuel servo too. 1 Quote Link to comment Share on other sites More sharing options...
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