Starting Trouble...anyone seen this before?

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shoffert
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Starting Trouble...anyone seen this before?

Post by shoffert »

I'm having a little trouble with starts on my '02.

The engine turns over fine, but won't catch until after I release the key...kind of like I'm using the starter to hand-prop it. My plane normally starts like a dream even when hot so I can work around it.

Mag drops are perfect on the left and right after it's running.

I have my guess as to the problem, but was wondering if anyone else had seen this before and knew the answer before I start digging. The plane did come out of annual recently.

I searched the forum for others to have asked before and didn't find anything.

Any help is appreciated!
-Steve
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Steve
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Re: Starting Trouble...anyone seen this before?

Post by Steve »

From your description, I would suspect a bad key switch.
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Re: Starting Trouble...anyone seen this before?

Post by shoffert »

My guess, too. I don't know enough about the SlickStart...I was afraid there might be some issue with it that could cause the problem.
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Re: Starting Trouble...anyone seen this before?

Post by Rich »

When the Slick Start is operating (powered off the starter relay, BTW), it grounds the left mag p-lead, disabling the 25-degree advance points and provides voltage/current to the retard points instead. In addition, when the starter ignition is selected, the right mag p-lead is also grounded by the ignition switch. If the alternate points in the left mag are bad or the conductor connection between the SS and these points is broken I would expect exactly this behavior. I did have this conductor go bad in my plane years ago.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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shoffert
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Re: Starting Trouble...anyone seen this before?

Post by shoffert »

Rich, can you elaborate on the conductor connection? Is that science speak for "wire"?!
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Re: Starting Trouble...anyone seen this before?

Post by Rich »

shoffert wrote: Mon Jul 13, 2020 11:22 pm Rich, can you elaborate on the conductor connection? Is that science speak for "wire"?!
Yeah it's "the wire". Sorry, I used to do all sorts of electric engineering for a living. Bad crimp, deteriorated insulation, even a break in the conductor inside the insulation are things I've encountered in various situations.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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shoffert
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Re: Starting Trouble...anyone seen this before?

Post by shoffert »

In which conduction connector did you find your problem? Mines the same year as yours.
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Re: Starting Trouble...anyone seen this before?

Post by Rich »

shoffert wrote: Tue Jul 14, 2020 10:29 am In which conduction connector did you find your problem? Mines the same year as yours.
The mechanic in the shop did this: He postulated a problem with the lead to the retard points and fashioned a temporary lead. Disconnected the lead at both ends (#3 SS terminal and the mag retard terminal), replacing it with his temp. The plane started right up normally. He went ahead and did a permanent replacement of both leads to the mag (#1 & #3 SS terminals).

Another thing that is worth checking is making sure the retard points are working. Disconnect the lead and connect an ohmmeter to that terminal on the mag and check that the points open as the prop is pulled through zero degrees.

And make sure power is being applied to the SS when starting. This is tricky because it is a side effect of energizing the starter.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Re: Starting Trouble...anyone seen this before?

Post by Rich »

BTW, I've posted some of this elsewhere, but my original Slick Start failed and was replaced some years ago with another. The original clearly failed the prescribed bench tests.

It was the replacement that was suspected a couple of years later, but it turned out to be the connection I described. Also, there are some errors in the AMM wiring diagram. The errors:

1. There was never a lead to terminal #2, which is intended to ground the right mag p-lead during the starting sequence. It's grounded by the ignition switch when starting. The replacement SS that was installed no longer even has a terminal #2.
2. The labels for left and right mag positions on the ignition switch are backwards. Change "L" to "R" and "R" to "L" and it's mostly correct.
3. The jumper that grounds the right mag during starting is missing. Note that if the #2 SS terminal is connected to the right mag, then this is not necessary. But of course it must be in place when this connection is there. The correction would be to show the jumper as part of the "L" area (now corrected) of the diagram.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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shoffert
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Re: Starting Trouble...anyone seen this before?

Post by shoffert »

I found out what was wrong...

In life I judge things by their "tragedy to comedy lapse rate"...with enough time everything becomes funny. For instance, if you blow a tire on the runway. Bad at the time; pretty funny about a week later.

This is already becoming funny.

A while back I set my "Essential Bus" switch to the proper position and planned not to touch it again until someday when I needed it to serve it's purpose.

Well...as it turns out...when that switch is activated (or inactivated, depending on how you look at it) it prevents electricity from going certain places (I have an '02 with steam gauges)...one of those places is where you need electricity to go to start the engine normally.

That switch is tough to figure out...when it's "ON" does that mean you've "engaged the cutout" and dropped electrical equipment or does being "ON" mean that the essential bus connected. My switch is getting a sticker telling me where it should live normally. I think it got flipped during the annual and I didn't catch it during ground ops.

Interestingly...besides the engine not starting normally, I didn't notice anything...steam gauges just work.

Many thanks to Rich for his great response. I really appreciate your help. No doubt someone on the forum will find this thread and your response will solve their problem!

Cheers,
Steve
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