Fiveboy Posted May 28, 2012 Share Posted May 28, 2012 Yesterday I flew (I have the engine on a gyroplane) and when I tried to accelerate I had an odd incident. The power remained where it was and there was no increase in rpm or thrust. The engine just continued at the setting it was on and then after two seconds or so, the power caught up to the new throttle setting. I managed to fly back home but now I want to check what would cause such a thing: plugs? Throttle sensor? Dirty map sensor.Dirty throttle body? In order of simplicity where should I look and what should I look for? Please copy to my email as well if you can. Thanks Rob Link to comment Share on other sites More sharing options...
davebugs Posted May 29, 2012 Share Posted May 29, 2012 Most acceleration issues I've experienced were a knock sensor. Look for cracks in it. Link to comment Share on other sites More sharing options...
ivans imports Posted May 29, 2012 Share Posted May 29, 2012 linkage sticking or ran at one rpm to long or iceing up Tb remember not ment to be in cold enviroment is uhasly under warm hood i think iceing up is limited heating on Tb mabee needs a extra coolant heater in air intake i see it in carbed vehicles all the time mostly on high humidity days have seen the whole carb blocked with ice and many planes crash cause of thiss on a car you just stop and let it warm up on a plane ummm how long can you glide for ? have been helping some airplane subaru guys here and there the 2.5 scares me is not known as a good engine in subaru world why 2.5 ? and not a 2.2 ? Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted May 29, 2012 Share Posted May 29, 2012 I could see a TPS possibly doing this. (i'd def. check any linkage too.) (also, spotted 2 ? marks in ivan's post - what do I win?) Link to comment Share on other sites More sharing options...
Fairtax4me Posted May 29, 2012 Share Posted May 29, 2012 Nothing, there's three! :-p Agree with Ivan that a 2.5 maybe isn't the best choice for an airplane engine. Do you have any way to hook up a diagnostic scanner to this setup? Have you checked all of the vacuum hoses and breather hoses? I'm not sure how much of the factory setup you carried over, but it seems like most of it should still be there in order for the crankcase to vent properly. Link to comment Share on other sites More sharing options...
ivans imports Posted May 30, 2012 Share Posted May 30, 2012 if you can show me some pictures i may have some ideas stock air box ? wire harness. The tps when it go's bad will give you dead spots in one place on throttle but should get better when you go below or above that it whould act up every time at same place in throttle. check main engine grounds and power distribution do you have a tach ? stock or aftermarket feul pump configuration and probly most important the elavation sensor and baro senser the cars know how thin the air is so should your plane. Link to comment Share on other sites More sharing options...
Fiveboy Posted June 2, 2012 Author Share Posted June 2, 2012 Yes! Careful examination shows that a cheap silicon gasket maker I used to seal the rubber part inside my seat tank gas cap had migrated into the tank (we sit on our gas tanks). This had become black snot and lodged into and throughout the first (paper see through) filter on the plane. After the fuel pump is another metal canister type. I have removed them both, flushed the tank and will be blowing out the fuel lines before reassembling with new filters. I looked at the plugs and they looked perfect. I may run some injector cleaner through the gas just to make sure everything is out. Link to comment Share on other sites More sharing options...
ivans imports Posted June 2, 2012 Share Posted June 2, 2012 dam your lucky thiss could have beed fatal mistake glad you found it are you useing a high preshure fillter ? a burst fillter in air whould be catasrofic make shure its high prshure fillter and lines even if carbed as preshures may change with altutdue i whould check the injector screens for debries and clean them. Link to comment Share on other sites More sharing options...
Fiveboy Posted June 8, 2012 Author Share Posted June 8, 2012 dam your lucky thiss could have beed fatal mistake glad you found it are you useing a high preshure fillter ? a burst fillter in air whould be catasrofic make shure its high prshure fillter and lines even if carbed as preshures may change with altutdue i whould check the injector screens for debries and clean them. I cut open the second metal gas filter (after the paper one that was fouled and before brand new the racing fuel pump) and it was totally clean. Nothing in it, so I am hoping my problem is isolated to before the fuel pump and I caught it in time. I am allowing the tank to dry out before I reinstall my feed lines (those are on the bottom of the seat which is the gas tank). I will then run some injector cleaner in a tank full and burn it off (on the ground at first and then in the air directly over the airport/runway). When there is a problem in the air you cannot just roll to the curb and park. Link to comment Share on other sites More sharing options...
travis1990 Posted June 9, 2012 Share Posted June 9, 2012 This might be a little off topic, but have you considered the frankenmotor? It's more powerful, just as reliable, and the sohc heads weigh less. I'm an aviation nut so i think of these things. Link to comment Share on other sites More sharing options...
Fiveboy Posted June 14, 2012 Author Share Posted June 14, 2012 I replaced all the gas lines from the seat tank to the secondary metal filter. Also the two filters (small plastic paper see through and canister metal). Also put in some injector cleaner and ran for almost an hour yesterday (including five crow hops down the runway). The fuel starvation issue seems cleared up. I will not feel confident until I have run all 8 gallons through though. New (minor) issues: I changed the plugs to Iridium. Now the machine seems to run just a tad hotter at the water temp sensor. Could this be because of new hotter burning plugs? Also the machine seems to now idle lower (maybe 1200 vs 1500) and had a tendency to stall. Air in the lines? Computer trying to "learn" new plugs?! Would a dirty MAF/MAP cause the lower rpm at idle? As regards Ivans query why a 2.5 vs 2.2 - no reason other than lots of people fly the 2.5 and I have a heavy tandem and a 2.2 wouldnt cut it for the lift I need. Can I even get carb icing with a FI engine!? Thanks Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 14, 2012 Share Posted June 14, 2012 I replaced all the gas lines from the seat tank to the secondary metal filter. Also the two filters (small plastic paper see through and canister metal). Also put in some injector cleaner and ran for almost an hour yesterday (including five crow hops down the runway). The fuel starvation issue seems cleared up. I will not feel confident until I have run all 8 gallons through though. New (minor) issues: I changed the plugs to Iridium. Now the machine seems to run just a tad hotter at the water temp sensor. Could this be because of new hotter burning plugs? Also the machine seems to now idle lower (maybe 1200 vs 1500) and had a tendency to stall. Air in the lines? Computer trying to "learn" new plugs?! Would a dirty MAF/MAP cause the lower rpm at idle? As regards Ivans query why a 2.5 vs 2.2 - no reason other than lots of people fly the 2.5 and I have a heavy tandem and a 2.2 wouldnt cut it for the lift I need. Can I even get carb icing with a FI engine!? Thanks what brand/number plugs did you use? Do you have scanner that could read the short and longterm fuel trims? It may well require a few cycles of heat-up/cool-down for the ECU to adjust to new plugs. Link to comment Share on other sites More sharing options...
Fiveboy Posted June 14, 2012 Author Share Posted June 14, 2012 what brand/number plugs did you use? Do you have scanner that could read the short and longterm fuel trims? It may well require a few cycles of heat-up/cool-down for the ECU to adjust to new plugs. Denso IK 20 Iridiums. Supposed to be the replacement for the stock plugs.... (?) Would taking the system off the battery and then letting it reset do anything good? I do not have a scanner. It would probably go nuts anyway because of all the custom mods to trick the engine into thinking its still on a car. I do have power steering but its by using a stick attached to a 27 foot rotor (LoL) Link to comment Share on other sites More sharing options...
Fiveboy Posted June 14, 2012 Author Share Posted June 14, 2012 Denso IK 20 Iridiums. Supposed to be the replacement for the stock plugs.... (?)Would taking the system off the battery and then letting it reset do anything good? I do not have a scanner. It would probably go nuts anyway because of all the custom mods to trick the engine into thinking its still on a car. I do have power steering but its by using a stick attached to a 27 foot rotor (LoL) BTW I do have a broad band fuel air metering sytem aside form what comes stock. The numbers when she was idling was at almost exactly perfect (like 14.8). I need to notice what she is reading under load when I take off and at cruise. These numbers will be changing shortly because I am about to depitch my prop some which will mean higher rpm and lower load under power. Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 15, 2012 Share Posted June 15, 2012 Denso IK 20 Iridiums. Supposed to be the replacement for the stock plugs.... (?)Would taking the system off the battery and then letting it reset do anything good? I do not have a scanner. It would probably go nuts anyway because of all the custom mods to trick the engine into thinking its still on a car. I do have power steering but its by using a stick attached to a 27 foot rotor (LoL) Most people run NGK. I dunno if anyone has reported any problems with Denso plugs. maybe others will chime in. Usually, I just ask questions based on reading posts from the actual smart people! lol! If you do a battery reset on the ECU, it will start the 'learning process' over again. So, might be better to just wait and try a few 'cycles' of running the engine to operating temp, letting it cool off, running again and monitor if the problem is getting better or not. Link to comment Share on other sites More sharing options...
Fiveboy Posted June 15, 2012 Author Share Posted June 15, 2012 Most people run NGK. I dunno if anyone has reported any problems with Denso plugs. maybe others will chime in. Usually, I just ask questions based on reading posts from the actual smart people! lol! If you do a battery reset on the ECU, it will start the 'learning process' over again. So, might be better to just wait and try a few 'cycles' of running the engine to operating temp, letting it cool off, running again and monitor if the problem is getting better or not. I will try a few cycles and see what happens. If it doesnt magically clear up I will reinstall the old plugs which looked perfect (only like 30 hours on them). Am I correct that if the manual calls for 15.5 foot pounds on the plugs, that is irrespective of the brand? Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted June 16, 2012 Share Posted June 16, 2012 I will try a few cycles and see what happens. If it doesnt magically clear up I will reinstall the old plugs which looked perfect (only like 30 hours on them). Am I correct that if the manual calls for 15.5 foot pounds on the plugs, that is irrespective of the brand? On an aircraft, I'm going to suggest you check the manufacturer's website or consult other experts. Also, I'm not sure re-installing the old plugs with the now-crushed original washers is 'advisable'. more on plugs (keep in mind, the beginning of the thread is from 2004); http://forums.nasioc.com/forums/showthread.php?t=518633&highlight=sticky+spark+plugs Link to comment Share on other sites More sharing options...
Fiveboy Posted June 16, 2012 Author Share Posted June 16, 2012 On an aircraft, I'm going to suggest you check the manufacturer's website or consult other experts. Also, I'm not sure re-installing the old plugs with the now-crushed original washers is 'advisable'. more on plugs (keep in mind, the beginning of the thread is from 2004); http://forums.nasioc.com/forums/showthread.php?t=518633&highlight=sticky+spark+plugs THANKS FOR THIS. I have saved it in my reference materials. Link to comment Share on other sites More sharing options...
unibrook Posted June 18, 2012 Share Posted June 18, 2012 I imagine one of the "tricks" you have to play on it is to ignore the fact that you don't use a front 02 sensor? Link to comment Share on other sites More sharing options...
ivans imports Posted June 19, 2012 Share Posted June 19, 2012 just plain jain NGK plugs the platnium ones and iridium one are hard to spark through and likes to jump down the side to ground have had many problems with thiss the simpler the plug the better it seems to work i do not like hot plugs in subaru engines. And i still think iceing could be a problem and should have more TB heat on a cold wett day could be a problem and would be no way to repiar it in air and the more throttle you give it the worse it whould get Link to comment Share on other sites More sharing options...
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