Lightspeed Ignition Misfire

I just came from the hangar where I had to cancel a flight when at run-up the Lightspeed ignition missed really bad.
It only has about 40 hours on it and has never been a problem except when a plug lead fell off and I found the installer had left 3 of 4 loose!
Not so lucky (?) this time. All were tight and the plugs don't look bad. I've searched the archives and saw one set of posts commenting on the other electrical connectors and will check those next. Any other ideas?
Thanks!

What type of crank position sensor do you have? Hall effect sensor in the mag hole, or flywheel magnets?

Things to rule out:
- spark plug wires hooked up correctly
- spark not "shorting" i.e. plug wires chafed on a baffle or something like that
- connectors at the coils on solid (check the wires & strain relief)
- phase test the coils (see the Lightspeed manual)
- crank position sensor wiring not damaged, connected properly at both ends
- voltage ok?

If all of this checks out, then it likely points to the crank position sensor. If you have one with flywheel magnets, the clearance between the sensor and magnets is specific.

If in doubt, call Klaus at Lightspeed. He has helped me out in the past when I thought I had a problem with my Plasma II.

Follow up

RVadmirer said:

I just came from the hangar where I had to cancel a flight when at run-up the Lightspeed ignition missed really bad.
It only has about 40 hours on it and has never been a problem except when a plug lead fell off and I found the installer had left 3 of 4 loose!
Not so lucky (?) this time. All were tight and the plugs don't look bad. I've searched the archives and saw one set of posts commenting on the other electrical connectors and will check those next. Any other ideas?
Thanks!

Click to expand...

So in the end...what was the problem.

light speed ignition

For what its worth,I work at united airlines in the engine test cell and spend alot of time with elec problems. My buddy built a chtistian eagle with dual light speeds.With only about 6 hours on the aircraft it started to miss once in a while. Every body was talking about valve problems but what I found after reading about it was that they had the wires for the hall effect pickups tied up with the RH lower spark plug wires. I also found a very small burn on one wire from the exhaust. Both were fixed at the same time and its been flawless sence then. I'll say one thing about that ignition is that it sure makes starting easier. I'm building an rv-8 and plan on using it

Interim Follow Up

Have been talking to Klaus. The wires he specifies to be kept 3" apart were run together through the firewall. And when I first got the plane back from the shop where the ignition was installed a plug wire had fallen off at run-up. Klaus says this is very bad for the coil. We are still troubleshooting. Will post the results when solved.

Dual Mags

A pair of Slicks will solve that problem! Cheap, redundant and self-generating.

RVadmirer said:

Have been talking to Klaus. The wires he specifies to be kept 3" apart were run together through the firewall. And when I first got the plane back from the shop where the ignition was installed a plug wire had fallen off at run-up. Klaus says this is very bad for the coil. We are still troubleshooting. Will post the results when solved.

Click to expand...

Anybody using safety wire or some other method to secure EI spark plug leads on the sprark plugs? I also had #3 lead come off Saturday... well it was detected on run-up during the mag off check. No earlier symptoms or signs of a problem was noted in the previous flight. Okay, back to the hangar, pull the cowl and plenum top just to find a #3 wire no longer snapped securely on the spark plug. Any Suggestions?

LifeofReiley said:

Anybody using safety wire or some other method to secure EI spark plug leads on the sprark plugs? I also had #3 lead come off Saturday... well it was detected on run-up dring the mag off check. No earlier symptoms or signs of a problem was noted in the previous flight. Okay, back to the hangar, pull the cowl and plenum top just to find a #3 wire no longer snapped securely on the spark plug. Any Suggestions?

Click to expand...

Secure the wires mid-run. They're probably wigglin' around in there.

FWIW, I use 4 of the plastic 2-wire guides (Klaus provides them), each secured to something. There is no "slack" in the wires whatsoever. No chance for them to move.

I recently had a problem with one of my coil terminals after 1800 hours, and it was directly due to one of the wire guides coming loose and working the terminal. You (the collective you -- we) really have to focus on getting those wires immobilized imho.

Forgot to mention...I ended up going with custom-length wires that I cut to fit exactly, with no extra/slack. The ones Klaus provided originally would have "worked" but weren't an exact fit. Less wire = less resistance + less chance of floppin' in the breeze. FWIW, I bought the MSD cut/crimp tool and some bulk MSD 8.5mm wire and 90* terminals (Klaus sells all of that, but I think I bought my MSD tool from Summit).

dan said:

Secure the wires mid-run. They're probably wigglin' around in there.

FWIW, I use 4 of the plastic 2-wire guides (Klaus provides them), each secured to something. There is no "slack" in the wires whatsoever. No chance for them to move.

I recently had a problem with one of my coil terminals after 1800 hours, and it was directly due to one of the wire guides coming loose and working the terminal. You (the collective you -- we) really have to focus on getting those wires immobilized imho.

Forgot to mention...I ended up going with custom-length wires that I cut to fit exactly, with no extra/slack. The ones Klaus provided originally would have "worked" but weren't an exact fit. Less wire = less resistance + less chance of floppin' in the breeze. FWIW, I bought the MSD cut/crimp tool and some bulk MSD 8.5mm wire and 90* terminals (Klaus sells all of that, but I think I bought my MSD tool from Summit).

Click to expand...

Hi Dan,

I have these black holders that the wires clip into. It has a center hole and I have the holders adel clamped to a push rod tube. The wires as delivered are a little long. I will make sure they're pulled tighter on the plug end at the next oil change. (5 more hours)

Thanks Dan!

A trick that might help keep this type of plug boot on is to push them on until one can feel the metal portion inside engage the plug. Then, while rotating slightly back and forth, advance the boot (the end towards the plug) a little more. Without doing this, it is easy to build some compression in the boot, which tries to push the connector away from the plug. Preferable is to have some tension in the boot, holding the connector onto the plug.

AlexPeterson said:

A trick that might help keep this type of plug boot on is to push them on until one can feel the metal portion inside engage the plug. Then, while rotating slightly back and forth, advance the boot (the end towards the plug) a little more. Without doing this, it is easy to build some compression in the boot, which tries to push the connector away from the plug. Preferable is to have some tension in the boot, holding the connector onto the plug.

Click to expand...

Thanks Alex, we'll add that to our bag of tricks.

Darrell

The CORRECT way to eliminate this problem

LifeofReiley said:

Anybody using safety wire or some other method to secure EI spark plug leads on the sprark plugs? I also had #3 lead come off Saturday... well it was detected on run-up during the mag off check. No earlier symptoms or signs of a problem was noted in the previous flight. Okay, back to the hangar, pull the cowl and plenum top just to find a #3 wire no longer snapped securely on the spark plug. Any Suggestions?

Click to expand...

Reiley,
Obviously, the folks giving you advice are not auto mechanics. Installing automotive style wires on spark plugs takes a bit of finesse. The reason the wire came off the plug is because of pressurized air. Automotive spark plug boots fit so tightly, that air gets trapped inside and is under pressure. This pressurized air can cause the boot to vibrate off. The proper technique is to use an O-ring pick (miniature ice pick) and a can of silicone spray.
First, apply silicone spray to the wire behind the boot and inside the boot. This will allow the boot to slide freely along the wire (once you get it moving). Next, carefully insert the O-ring pick between the insulation of the wire and the boot. Spray more silicone spray (Gary's It is one brand) into the gap between the pick and the wire. Dish soap and water will substitute for Silicone Spray in a pinch. Make sure you get the sharp end of the wire all the way past the area where the boot firmly contacts the insulation of the plug wire. Slide the boot back an inch or two on the wire, leaving the pick in place. Install the wire on the spark plug (or the coil end for that matter) till you hear the metal terminal "click" in place. Now advance the boot with the O-ring pick, over the spark plug. The pick creates a space to allow the air to escape. You are now ready for the next plug.
An alternate method is to install the wire on the plug and then insert the O-ring pick till you hear the pressurized air hiss out. Using this method, make sure that the terminal is "clicked" onto the plug. It is also good practice to apply a dab of Permatex dielectric tune up grease between the terminal on the spark plug and the terminal on the wire. Same holds true at the ignition coil end. The grease is available at all auto parts stores.
The wire will not come off when done this way. If the boot tried to back out, a vacuum would be formed, preventing it from coming off.
Charlie Kuss
PS The purpose of the grease is to prevent corrosion between the terminals

chaskuss said:

Reiley,
Obviously, the folks giving you advice are not auto mechanics. Installing automotive style wires on spark plugs takes a bit of finesse. The reason the wire came off the plug is because of pressurized air. Automotive spark plug boots fit so tightly, that air gets trapped inside and is under pressure. This pressurized air can cause the boot to vibrate off. The proper technique is to use an O-ring pick (miniature ice pick) and a can of silicone spray.
First, apply silicone spray to the wire behind the boot and inside the boot. This will allow the boot to slide freely along the wire (once you get it moving). Next, carefully insert the O-ring pick between the insulation of the wire and the boot. Spray more silicone spray (Gary's It is one brand) into the gap between the pick and the wire. Dish soap and water will substitute for Silicone Spray in a pinch. Make sure you get the sharp end of the wire all the way past the area where the boot firmly contacts the insulation of the plug wire. Slide the boot back an inch or two on the wire, leaving the pick in place. Install the wire on the spark plug (or the coil end for that matter) till you hear the metal terminal "click" in place. Now advance the boot with the O-ring pick, over the spark plug. The pick creates a space to allow the air to escape. You are now ready for the next plug.
An alternate method is to install the wire on the plug and then insert the O-ring pick till you hear the pressurized air hiss out. Using this method, make sure that the terminal is "clicked" onto the plug. It is also good practice to apply a dab of Permatex dielectric tune up grease between the terminal on the spark plug and the terminal on the wire. Same holds true at the ignition coil end. The grease is available at all auto parts stores.
The wire will not come off when done this way. If the boot tried to back out, a vacuum would be formed, preventing it from coming off.
Charlie Kuss
PS The purpose of the grease is to prevent corrosion between the terminals

Click to expand...

Sweet... I put his in the file too.

Thanks!

Watch the coil(s)

I know it's kind of late to post to this thread.

I have a Slick mag on the upper plugs and a Lightspeed on the lower plugs of my Glasair III. A few weeks ago I was flying and thought I noticed some roughness, so checked both ignitions and, sure enough, the Lightspeed was missing on number 2 (EGT on each cylinder makes this super-easy to diagnose). Pulled the cowls and sure enough the #2 lead had come off the plug. Pinched the contact ring a touch and buttoned it up, and lo and behold it was still missing on #2.

Turns out that the coils used by Lightspeed are especially sensitive to being run without being connected to a plug. Maybe 45 minutes of run time had roached the coil with the high tension lead voltage unconstrained.

Moral of the story is to suspect the coil if you realize you've run for any period of time without a plug connected. Buy an extra because you'll need it. I still love the Lightspeed, though. Easy starts and smooth running when it's all connected properly.

-Steve Metzger
RV8AQB - Fuselage in progress

Same thing

smetzger said:

I know it's kind of late to post to this thread.

I have a Slick mag on the upper plugs and a Lightspeed on the lower plugs of my Glasair III. A few weeks ago I was flying and thought I noticed some roughness, so checked both ignitions and, sure enough, the Lightspeed was missing on number 2 (EGT on each cylinder makes this super-easy to diagnose). Pulled the cowls and sure enough the #2 lead had come off the plug. Pinched the contact ring a touch and buttoned it up, and lo and behold it was still missing on #2.

Turns out that the coils used by Lightspeed are especially sensitive to being run without being connected to a plug. Maybe 45 minutes of run time had roached the coil with the high tension lead voltage unconstrained.

Moral of the story is to suspect the coil if you realize you've run for any period of time without a plug connected. Buy an extra because you'll need it. I still love the Lightspeed, though. Easy starts and smooth running when it's all connected properly.

-Steve Metzger
RV8AQB - Fuselage in progress

Click to expand...

This exact same thing happened to a RV-6 buddy of mine too.
His was the #1 bottom plug wire.
He now keeps a spare coil.
Klaus recommends a single EI system be installed on the TOP plugs and
I'm pretty sure it has to do with flame front performance, but it sure helps
with plug wires not falling off as well.

same with a Slick mag

Not just with EI coils, but an open or high resistance plug or wire will also take out a Slick magneto. Will burn the the rotor and associated stator. Ask me how I know. Slick 4370 = $635 fm Spruce.....it's only money and time.