Electrics Posted May 28, 2011 Share Posted May 28, 2011 Engine starts fine once you get the light. But it has had a history of not starting and you don't get the light and no rotation. We have an APU. When you take the Engine bleed air switch to override and push down on the start switch you get no rotation. We have changed the starter control valve and the bleed air regulator ad shutoff valve. We load lighted the starter control valve cannon plug and its good. Need some assiatance please. Quote Link to comment Share on other sites More sharing options...
Steve1300 Posted May 29, 2011 Share Posted May 29, 2011 Assumptions: (1)you have good bleed air manifold pressure; (2) you visually verified that your engine bleed air regulator valve goes open when the switch is placed to override; (3) your starter switch works each and every time, and (4) you disassembled the backshell on all the electrical connectors to see that you can't be experiencing intermittent "opens." At that point, I'd look at the engine start interlock system to make sure that my oil shutoff valve circuit breaker is not complicating the mess. Have you also looked at the start control CB? It is a good thing you are "electrics" as this sure looks like an electrical problem to me. Quote Link to comment Share on other sites More sharing options...
NATOPS1 Posted May 29, 2011 Share Posted May 29, 2011 Before you place the start switch to start (every time) press to test the start valve open light... If the light illuminates both the start control CB and oil CB are in (good) and your interlock relay is energized and good.... Power flows from the start control CB to the interlock relay. Power from the oil CB energizes the interlock relay which then allows power from the start control CB to flow to the start switch and the start valve open light. How long do you "wait" before you discontinue the start cycle after no light/ no rotation? (wait the FULL 5 secs?) (maybe "wait" a bit longer we had one engine that 80% of the time took a little bit longer...) If you start #4 and use high pressure air does it have the same issue (no start)? What is your APU air pressure output? Quote Link to comment Share on other sites More sharing options...
tusker Posted May 29, 2011 Share Posted May 29, 2011 I used to be top notch on starting problems!!!....I never missed one but!!!!....it's a long time ago. The system seems to be different. So I shut up!!....................Réj................the..John Boy Quote Link to comment Share on other sites More sharing options...
Ben Legere Posted May 29, 2011 Share Posted May 29, 2011 That's an easy fix. The start switch may have worn or has dirty contacts. If you are getting power through it you may not be getting enough amperage to the starter control valve. Try swapping the switch out. It works most of the time. Quote Link to comment Share on other sites More sharing options...
tusker Posted May 30, 2011 Share Posted May 30, 2011 Shit!!!..........Ben............When a guy says it's an easy one!!!..........you must be a genius.......that's what we need!!! Go for it!!! Quote Link to comment Share on other sites More sharing options...
NATOPS1 Posted June 1, 2011 Share Posted June 1, 2011 Electrics is this the same aircraft with the Gen problem (#3 Gen falls off line?) Quote Link to comment Share on other sites More sharing options...
Electrics Posted June 1, 2011 Author Share Posted June 1, 2011 It sure is but to fix this problem we changed the engine pls it was leaking oil. Then generator problem came with the new Engine. Quote Link to comment Share on other sites More sharing options...
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