edwardlcy Posted May 17, 2011 Share Posted May 17, 2011 HI all, C-130H having this snag #3 TIT 30C higher compared to other engines at same fuel flow settings across all throttle range, TQ and rpm are normal though.. Rectification done: - TD Amp calibrated and adjusted - TD amp replaced and calibrated - TD valve replaced - 18 thermocouples replaced - thermocouple harness replaced - TIT indicator replaced - ECTM converter replaced - coordinator cx satis - anti icing valve func cx satis Snag still persist Any ideas? Quote Link to comment Share on other sites More sharing options...
Lkuest Posted May 17, 2011 Share Posted May 17, 2011 What if your fuel flow and torque are lying to you? Quote Link to comment Share on other sites More sharing options...
pjvr99 Posted May 17, 2011 Share Posted May 17, 2011 What about T-block and Y-lead? I realize this is a long shot (and difficult), try swapping the indicator and amp wires around on the T-block - only allowed 6·C difference at same throttle position. Also try disconnecting at firewall, gauge, and T-block, then do resistance checks between the chromel-alumel wires and also to ground. In all cases there should NOT be any continuity . . . . Something else to try, use your TD tester to shoot TIT signal to cockpit Good luck, let us know what you find Quote Link to comment Share on other sites More sharing options...
edwardlcy Posted May 17, 2011 Author Share Posted May 17, 2011 What about T-block and Y-lead? I realize this is a long shot (and difficult), try swapping the indicator and amp wires around on the T-block - only allowed 6·C difference at same throttle position. Also try disconnecting at firewall, gauge, and T-block, then do resistance checks between the chromel-alumel wires and also to ground. In all cases there should NOT be any continuity . . . . Something else to try, use your TD tester to shoot TIT signal to cockpit Good luck, let us know what you find sorry but what do you mean by T-block and Y-lead and wheres the location? and by chromel-alumel wires are they the ones connected to thermocouples? Quote Link to comment Share on other sites More sharing options...
pjvr99 Posted May 17, 2011 Share Posted May 17, 2011 A little new to these engines then? Okay, T-block is located on the upper left side of the combustion case - used to connect the two thermocouple harnesses together. Next, the Y-lead - takes the signal from the T-block through the fireseal, and then splits to connect to the TD amp, and back to the firewall for the indicator signal. T-block part no: 6840004 Y-lead part no: 6847718 By the way, what is an 'ECTM converter' .......?? Another question: are the throttles lined up above X-over? Quote Link to comment Share on other sites More sharing options...
tusker Posted May 19, 2011 Share Posted May 19, 2011 .......I suppose you checked it out in Null.........and no throttle split!!..........I beleive that above crossover, you're on Temp schedulling. Maybe the TD system reads the right temp but, not the indicator. Keep on diggin' boy!! Find that little bastard snag!! Quote Link to comment Share on other sites More sharing options...
yawdamper Posted May 20, 2011 Share Posted May 20, 2011 Did this engine just suddenly get 30C hotter? Is there a baseline for this engine? EWngines wear and as they do they run hotter. Is this engine out of limits? If it is a sudden increase in temp the thermocouple system may be in question, but don't forget to look for bleed air leaks. Does this engine have a trim thermocouple? If so it may also have a trim resistor. Quote Link to comment Share on other sites More sharing options...
Ben Legere Posted May 20, 2011 Share Posted May 20, 2011 Haha, that's an easy one. Check your bleed valves. Close your engine bleed then check the engine anti-ice to see if you get a 24 degree rise. If you get less than 24 degrees TIT rise, lets say it only rises 18 degrees you have a stuck bleed valve, if you get no rise at all your anti-ice valve is stuck open or your bleeds are just stuck open. Check it in null too. Does it have oil cooler augmentation? Quote Link to comment Share on other sites More sharing options...
Ben Legere Posted May 20, 2011 Share Posted May 20, 2011 Haha, that's an easy one. Check your bleed valves. Close your engine bleed then check the engine anti-ice to see if you get a 24 degree rise. If you get less than 24 degrees TIT rise, lets say it only rises 18 degrees you have a stuck bleed valve, if you get no rise at all your anti-ice valve is stuck open or your bleeds are just stuck open. Check it in null too. Does it have oil cooler augmentation? Quote Link to comment Share on other sites More sharing options...
herky400M Posted May 20, 2011 Share Posted May 20, 2011 I agree with PJVR, did you do the test with the td-tester and put cetain TIT values thru this tester and it should indicate whitin 6°C TIT. Quote Link to comment Share on other sites More sharing options...
Lkuest Posted May 20, 2011 Share Posted May 20, 2011 Perform all the TD system checks with the engines running. Max Start TIT, Crossover, Max Auto, Temp Limiting (leach all the air off that motor that you can in order to get it to overtemp.) If all those checks are normal, then your TD system and Indication systems agree with each other. Did you do a Torque Cal on all 4? You should only compare all 4 engine TIT's and torques with bleed air valves closed. Hooking up the TD tester to the firewall TIT harness is a step I love using when troubleshooting these write-ups. What else has been done so far? Quote Link to comment Share on other sites More sharing options...
pjvr99 Posted May 20, 2011 Share Posted May 20, 2011 Haha, that's an easy one. Check your bleed valves. Close your engine bleed then check the engine anti-ice to see if you get a 24 degree rise. If you get less than 24 degrees TIT rise, lets say it only rises 18 degrees you have a stuck bleed valve, if you get no rise at all your anti-ice valve is stuck open or your bleeds are just stuck open. Check it in null too. Does it have oil cooler augmentation? Not true: bleed valves will not affect TIT rise at LSGI and NGI, below X-over, or in NULL. The 24°C rise is created when scoop anti-icing and inlet anti-icing are functioning correctly. A lesser rise will indicate one or both a/icing side valves, and/or a/icing solenoid valve inop and/or scoop valve inop. Now: the only way to figure out what's happening is to do man-on-stand. Start engine, and at NGI, lightly touch fingers to side valve(s) and feel if they're hot: if so, valve(s) are open. If cool have cockpit open engine a/icing for a minute, and touch again. If still cool, valve(s) are closed. In either case the problem may lie with the side valves stuck open/closed, or with the solenoid valve which controls them being inop. A hand held over the scoop vent on the RHS of the inlet duct will tell you whether the scoop valve is functioning as required. Quote Link to comment Share on other sites More sharing options...
pjvr99 Posted May 20, 2011 Share Posted May 20, 2011 To get back to the origional problem, my feeling is a wiring problem. Maybe a dry joint in a cannon plug at a pressure break, firewall, in a lead. Having reread the original post, he does says at all power settings ...... torq should not be used as a comparative reference as a 98% engine wil have much less torq than a 108% engine, especially once throttle is above x-over. If the TD systems on symmetrical engines are good, TIT should be near identical with throttles above x-over lined up. Fuel flows on engines should be very close, but may differ for a number of reasons. RPM should be 99.75% to 100.25% Quote Link to comment Share on other sites More sharing options...
tusker Posted May 20, 2011 Share Posted May 20, 2011 Hey Ben!!........you mean to tell us that if you get an oil temp augmentation,......you get a TIT augmentation!! And also I'D like to mention that Yawdamper makes sense too with bleed air leaks and old age engine(just like me as a matter of fact). #3 is always the first one to get the kick in the ass to start and to wake up the other ones after!!................John Boy Quote Link to comment Share on other sites More sharing options...
Lkuest Posted May 21, 2011 Share Posted May 21, 2011 Hey Ben!!........you mean to tell us that if you get an oil temp augmentation,......you get a TIT augmentation!! Yes, actually, you do. The more bleed air systems you run off a motor, the higher the TIT is. Air valves go bad all the time, and oil cooler augmentation comes right off of the diffuser. I think what he was getting at was was just to check the augmentation system for leaks if it comes equipped. Quote Link to comment Share on other sites More sharing options...
tusker Posted May 27, 2011 Share Posted May 27, 2011 ........Copy!!!! Quote Link to comment Share on other sites More sharing options...
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