Slick Starter Module

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Barry
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Slick Starter Module

Post by Barry »

Had an interesting issue occur this weekend. On Saturday I flew doen to KCVN from KEIK, about a 2h45m flight. I normally check my engine screen about once ever 20 minutes to look specifically at EGT and CHT. About 40 minutes out at 9000 ft I noticed that the EGTs were a little off from normally. Specifically cylinders 1 & 3 were showing higher than normal EGT from where they were set at the beginning of the flight. Typically my #3 cylinder runs the hottest EGT and therefore is used for leaning. As is normally the case I lean to a temperature of 1435 degrees F on this cylinder... very very consistent. The other 3 cylinders normally settle in with degrees of this temperature. This results in a cyclinder head temperature of about 360 degrees F across the board. My fuel burn at this point is 10.2 gal/hr at 140 true airspeed. MP at 9000 ft was 22.1""hg and rp,s were set at 2530. Again all totally normally. But when I checked the screen at about 2 hrs into the flight for at least the 4th time, the EGT on #1 and #3 were higher than normal up at about 1490 degrees F. Everything else was totally normal. I increased the mixture just a little and and brought the EGTs back to 1435. Again, no other issues. Landed and shutdown uneventfully. On Sunday morning, the plane wouldn't start no matter what I tried. Everything was normal except for the fact that there seemed to be no spark, nothing even close to wanting to turn over. Keep in mind that this airport is in the middle of nowhere, New Mexico. But I was successful in getting the local mechanic out in about 15 minutes to take a look. He did a little trouble shooting... checked the mag timing, pulled the plugs... fuel flow... everything was perfect. So now the question is what is going on with the left mag... the plane of course starts on the left mag. Wasn't much else he could do at the moment, and he wasn't totally familiar with the Slick Start system. So we decided to tow the plane to the maintenance hangar and await the chieff mechanic's return from a flight. In the meantime I did a little research on the starting circuit and that started to point me to the Slick Start module... but it didn't seem to explain the EGTs during the flight because the Slick Start is technically disengaged once the plane has started. This morning a more formal test of the Slick Start based on the maintenance manual proved that to be the failure mode. So the part was ordered and hopefully it arrives Tuesday afternoon. Its literally a 5 minute install. I caught a new commuter flight back to Denver (only one on the Dornier Jet) and will head back down later in the week to fly 4ES back home.

I found a link on the PilotsofAmerica.com site that had a post of the exact issue in an RV. Same symptoms, but unfortunately he spent $1000 for a new mag that was not needed. After he found no change with the new mag, he tried disconnecting the Slick Start and his EGTs came back to normal. So I think we figured this out. But what I haven't figured out yet is why the Slick Start failure caused the EGTs to vary on #1 and #3 cylinders while in normal cruise. I'm also not sure why the RV was ableto be started with a bad Slick Start module. In the case of the DA40, the left mag does not have an impulse coupling normally found on planes without a Slick Start module. So perhaps the RV has a different setup depending on what engine he used.

Has anybody run into this issue? Does anybody have an explanation before I call Champion Tech support?
Barry Starkman
Commercial Instrument
DA40 N984ES 40.827
KEIK - Erie, CO
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Rich
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Re: Slick Starter Module

Post by Rich »

Ah, Erie, CO. Slowly I turned. The last flight of my old Cherokee. But I digress...

When the SS is activated it grounds the p-lead of the left mag and provides power through the alternate, retard points, which should be at zero degrees. Could there be a failure mode of the SS which causes grounding of the left mag and some feedback through the retard breaker, making it fire late? A real mystery would be why just the right-side cylinders would seem to be affected.

From the wiring diagrams:
SlickStart.jpg
There is an error (at least for my plane) in that terminal #2, which grounds the right mag during start, was never wired in my plane. And in fact, the newer SS units no longer have this terminal (mine was also replaced some (years back)
2002 DA40: MT, PF, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210.
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Re: Slick Starter Module

Post by MarkA »

Barry, sorry to hear you got stuck in New Mexico.

This is just a wild-ass guess but if you advance the timing in cruise (like the SureFly ignition does) without changing the fuel flow, you'd expect a reduction in EGTs and an increase in CHTs for the same fuel flow. The reason being more fuel is being burned in the cylinders rather than going out the exhaust.

Similarly, if you retard the timing in cruise without changing the fuel flow, you'd expect just the opposite - higher EGTs and lower CHTs which it sounds similar to what you were seeing.

So I wonder if is's possible that the right mag was still firing at the normal ~25 degrees before top dead center but the left mag was either not firing at all or firing way late at top dead center due to the failure in the SlickSTART. The net effect might be enough to retard the combustion event enough to explain the EGT temperature change.
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Re: Slick Starter Module

Post by Rich »

it's possible that the RV has SS on one mag and impulse coupling on the other. I've seen this, and I believe the DA40-F has this setup.
2002 DA40: MT, PF, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210.
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Rick
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Re: Slick Starter Module

Post by Rick »

Barry, any chance you could post the data log file from your flight to the Reports section of the DAN? That might give the experts something to look at for more clues...
2007 DA40 XL - Roanoke, VA (KROA)
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Barry
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Re: Slick Starter Module

Post by Barry »

Great idea... unfortunately the plane is in NM and I am back Colorado, but I’ll see if I can get the mechanic to down load it and email it to me. Thanks!
Barry Starkman
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DA40 N984ES 40.827
KEIK - Erie, CO
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Re: Slick Starter Module - Epilogue

Post by Barry »

Well it turns out it wasn't the Slick Start module after all. After trying a new module with no success the mags were pulled and sent back to American Magneto up in Montana. They were rebuilt there at just over 1000 hours which was about 450 hours ago. They found that the secondary coil on the left mag had a broken winding wire. As they described it to me, the wire used for the winding is like the thickness of a human hair... very fragile and a weakpoint in the design. When that wire broke during flight, it started to arc between the 2 ends, providing lower energy spark to those plugs, hence only a slight EGT increase and a continued smooth running engine. However, when I tried to start the plane the next day, the Slick Start put 20000 volts onto that coil and the resulting arc blew a hole in the coil making it useless and created the non-start situation. American Magneto turned around the repair quickly completely under warranty including overnight shipping both ways. They also completed a 2017 service bulletin on the failing distributor gear at no charge. Now I'm just waiting for the mags to get back in the plane so I can go down to New Mexico and bring her home.
Barry Starkman
Commercial Instrument
DA40 N984ES 40.827
KEIK - Erie, CO
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Chris B
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Re: Slick Starter Module - Epilogue

Post by Chris B »

Barry wrote:
Thu Jun 18, 2020 8:00 pm
Well it turns out it wasn't the Slick Start module after all. After trying a new module with no success the mags were pulled and sent back to American Magneto up in Montana. They were rebuilt there at just over 1000 hours which was about 450 hours ago. They found that the secondary coil on the left mag had a broken winding wire. As they described it to me, the wire used for the winding is like the thickness of a human hair... very fragile and a weakpoint in the design. When that wire broke during flight, it started to arc between the 2 ends, providing lower energy spark to those plugs, hence only a slight EGT increase and a continued smooth running engine. However, when I tried to start the plane the next day, the Slick Start put 20000 volts onto that coil and the resulting arc blew a hole in the coil making it useless and created the non-start situation.

Hi Barry -

Thanks for the detailed follow-up. :thumbsup:

Your situation illustrates the primary reason that we may eventually replace the RH magneto with a SureFly Ignition Module. Different failure modes for normal operation and starting, with (hopefully) better overall reliability. Plus, access to the RH magneto for maintenance is a PITA.

But after some of my recent misadventures I plan to let others go first... ;)

Chris
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