Light Speed Ignition running rough

[Stroh21]

Thank you for the tips!

[cderk]

Originally Posted by SPX

The message above well describes an issue that I had a year or so ago. When on the electronic ignition, the engine ran awful, and at times, barely ran. After some head scratching, it was the DB-9 connector that had the problem.

Boy, this certainly doesn’t give me a warm fuzzy feeling. I have dual light speeds and so far it seems to be working OK

[vic syracuse]

I have found the lightspeeds to be reliable, but as with any system on our aircraft, they need inspection and TLC at regular intervals.

Dan mentioned the wires. I've always replaced those at 5 yrs as spec'd. The coils should be checked for proper resistance, at least once per year. They should normally be around 8.1K to 9.3 K ohms. They tend to get higher than that before they hard fail, so if you are checking them regularly you shouldn't have a hard coil fail.

It's in my book.

Vic

[flion]

I bought a bunch of extension screws with knurled knobs (https://www.amazon.com/10-PACK-Screw.../dp/B016S7OBOE) so I could tighten and verify tightness by touch. I replace them on every connector that relies on those to secure the connection. Inspired by one of the connectors on my dual lightspeed setup getting loose but it was incredibly difficult to get a screwdriver in where it was mounted (20/20 hindsight about mounting location fixed when panel was upgraded). That and one spade connector failed (my fault) on one of the coils which produced the symptoms described by the OP and was easily fixed once spotted. The control boxes seem bulletproof but I worry how long the system will be available. I'm discovering that these kind of systems don't have the lifespan I'd want to count on.

[deek]

Originally Posted by flion

The control boxes seem bulletproof but I worry how long the system will be available. I'm discovering that these kind of systems don't have the lifespan I'd want to count on.

I've had Klaus' Plasma II system on one of my planes (same box) for 31 years.

[Stroh21]

Thank you to everyone for the replies. The support here is what makes this community great! I began tracing wires and found one that had become disconnected in the forward baggage compartment. In the end, totally my fault and felt pretty silly after finding it. Fortunately, now I have new spark plugs on top and everything else is running great again! Also learned a lot, which is also a bonus! “Thank you“ to everyone again.

[vic syracuse]

I have found the lightspeeds to be reliable, but as with any system on our aircraft, they need inspection and TLC at regular intervals.

Dan mentioned the wires. I've always replaced those at 5 yrs as spec'd. The coils should be checked for proper resistance, at least once per year. They should normally be around 8.1K to 9.3 K ohms. They tend to get higher than that before they hard fail, so if you are checking them regularly you shouldn't have a hard coil fail.

It's in my book.

Vic

[Caveman]

I hope I don't jinx myself. Here's another positive data point for Lightspeed. I've been running one crank triggered Lightspeed Plasma II and one Slick 4371 for 12 years and almost 900 hours. For comparison, I've complied with one Slick AD and 1 or 2 Slick service bulletins during that time. I rebuilt (IRAN) the Slick myself about 9 months ago.

The Lightspeed has been rock solid to this point. It is installed with the brain box not on the firewall but under the panel on a rib to help with cooling. Extra care for the trigger wire routing and extra support at the coil connectors was taken. No parts or wires have ever been replaced, other than spark plugs. I did purchase a spare coil recently just in case. My biggest concern would be a manifold pressure sensor failure which I understand can advance the timing too far in flight.

I believe any of these systems can have issues. If it has moving parts it will have wear at some point. I've had some recent experience helping a friend with P mags and they certainly have their own idiosyncrasies to watch for. Although I'm watching the Sure-Fly with interest for a possible future Slick replacement it would require electrical system surgery to add another battery or alternator for redundancy and I'm not ready to go there on a VFR airplane. I like simple and light.

[Stroh21]

The maintenance tips are awesome. Thank you! I’m definitely a fan of preventative maintenance.

[Alan Carroll]

Originally Posted by Stroh21

Thank you to everyone for the replies. The support here is what makes this community great! I began tracing wires and found one that had become disconnected in the forward baggage compartment. In the end, totally my fault and felt pretty silly after finding it. Fortunately, now I have new spark plugs on top and everything else is running great again! Also learned a lot, which is also a bonus! “Thank you“ to everyone again.

Matt,

Glad you found the problem. Out of curiosity, what wire was disconnected?