@Charly posted:... Any more thoughts or ideas.
Is it impractical or have you otherwise ruled out opening engines to examine the wire routing per Engineer-Joe's response?
Idea 1. For the engine that properly starts only 1 out of 7-10, when you do gain control of the engine can you run a Track Signal Quality test? This is the one where you want to get 9-10 rather than 1-2. If you get a low or mid scale reading does it materially change if you move the engine to a different position in the block...such as right where TIU power enters the block (e.g., at a lock-on).
Idea 2. Is it practical to swap the red/black power cables at the TIU output to a different output. For example, if the block in question is being powered by Variable 1, can you swap the cables right at the TIU with Fixed 1; I figure it's only a couple inches apart so might not be too difficult to swap? Thinking: there is some evidence that TIU channels can lose signaling performance in some environments. Secondary thinking: even when operating in "fixed" mode, a Variable TIU channel has internal electronics between input and output. OTOH, a Fixed TIU channel is essentially a straight shot from input to output. So with the same reasoning discussed by others that DC power is the "best" environment for DCS signaling, it stands to reason that a Fixed TIU channel might have better DCS signaling than a Variable. This latter thought may be in the noise...but you did ask for more thoughts!
