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  #31  
Old 03-12-2017, 03:58 PM
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You are using the ACS A-510-2 switch?



Hummmmmm I see your dilemma. grrrrr Big Pic.....sorry


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  #32  
Old 03-12-2017, 04:03 PM
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Here's another good discussion...

http://www.vansairforce.com/communit...magneto+switch

Still sticking with return grounding....




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  #33  
Old 03-12-2017, 04:03 PM
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Affirm! That's it.
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  #34  
Old 03-12-2017, 05:34 PM
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Quote:
Originally Posted by Dave Bernard View Post
Affirm! That's it.
Wow, That's great news Dave!

But before I start my cat happy dance....how were you able to verify so quickly?

Working out of your hanger?




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  #35  
Old 03-12-2017, 07:10 PM
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Haha- no not "that is the solution" - that is the switch I am using!

Gotta keep troubleshooting tomorrow.
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  #36  
Old 03-12-2017, 09:15 PM
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Quote:
Originally Posted by Dave Bernard View Post
Haha- no not "that is the solution" - that is the switch I am using!

Gotta keep troubleshooting tomorrow.

Rats! Forgot my own question...Doh Thought that response was way to quick!


Well, to make it up I found this helpful.





Good luck tomorrow.




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  #37  
Old 03-12-2017, 10:28 PM
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I "may" have figured the solution (fingers crossed):

The ACS switch diagram does not show the ignition wires as shielded (and has not been revised since 2001...). With the ACS switch wired with shielded wires connected only at the magneto end, and the ground post wired directly to the airframe ground, I ASSume that I may be grounding the mags in all switch positions.

If I were to ground the shields on the switch end to the switch ground post, and not directly to the airframe, I would be getting the desired grounding action through the shields back to the magnetos.

I'm thinking of disconnecting the ship ground from the ground post of the switch, and running some temp wire from the switch ground post out to the shielding ground post on the mags, strictly for test purposes before I mangle up my P-lead wires switch side.

Thoughts?

I found this thread helpful.

SECOND EDIT:

I am concerned that wiring both shield wires to the center ground post could inadvertently ground both mags when you only desire one- thus not allowing a mag check or even starting. Should the right P-lead shield ground to the jumper terminal, and the left p-lead shield ground to the center post on the switch?? Am I over-thinking?
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Last edited by Dave Bernard : 03-12-2017 at 10:50 PM. Reason: added link
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  #38  
Old 03-12-2017, 10:50 PM
Mlew Mlew is offline
 
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I had the same issue. Turns out there were a couple of very small wires from the shielding that were grounding out at the back of the key switch. Very hard to see. cut back the shielding to be sure no wires grounded the key switch.
thanks,
Mark
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  #39  
Old 03-13-2017, 10:49 AM
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Default Deja vu all over again....

Yep it seems this issue has been around for a bit. I mean 4 different wiring options in this thread alone, and of few more in the forums...But it seems to me that the most recommend one is the return ground thru wire shield. As per this diagram...

http://www.aeroelectric.com/articles...tchOptions.pdf

So Dave, I'd eventually wire it as per the diagram above. No, the double wire shields will not be an issue.( see the switch contact points operation above... Note: R and the ground next to it are jumped together at the terminals, so the diagram is a bit skewed.)

Now that being said...they all try and I believe do achieve the same basic end results. But some with unwanted and possibly damaging effects. I'll leave the debate about good, best, and better, for another time. Which I think Dave alluded to with his can of worms....


So leaving your wiring as is ....it should still work.




Back to troubleshooting...


First...Is L terminal at the switch REALLY grounding out whilst starting. (Wiring or switch problem)

Secondly... Will the Left mag start the engine on it's own.
(Mag issue)

I leave it to your expertise on finding the results but if I were asked to recommend something...

For 1) Take out the starter fuse. (no power to the switch, and starter contactor) and check for continuity between L terminal on switch, and ship ground with the switch turned to the start position. Note...engine should not turn over, and I don't believe that any voltage will be present at the terminal with all wiring as is. But perhaps removing L plead from L terminal would be wise. Replace fuse...

For 2) Leave Left mag plead disconnected from terminal L on starter switch, and see if it starts!

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Last edited by Tommycat : 03-13-2017 at 11:11 AM.
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  #40  
Old 03-13-2017, 12:25 PM
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Default Another possibility

I thought mine was wired per Vans diagram, I cranked and cranked. About when I gave up and let go of the key the engine fired. Turned out I had the left and right p-leads reversed grounding the left mag for starting. How did I do that? Vans diagram shows the p-leads, J3 and J4 to the right and left mags, right on the left, left on the right. I looked at the diagram instead of reading.
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Last edited by dlloyd3 : 03-13-2017 at 01:34 PM.
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