[Geico266]

I may have found a potential problem with the factory supplied Light Speed Ignition wiring harness. Out of an abundance of caution I decided to "go public" with what happened in hopes of preventing someone else from having an in-flight problem.

I found the cover of the factory supplied wiring harness had melted after completing a standard EGT test for “balancing” the fuel injectors. The cover had melted to the point of sagging and having holes in it. The wiring may or may not have been damaged, but I did experience problems with the LSE Plasma II in flight and had to shut it down to continue flying. The installation appeared to be per the RV-10 plans and LSE Plasma II install per specs using proper techniques and distances from the exhaust pipes. There were no exhaust leaks.

This appears to have happened when I ran the engine at peak EGT's for about 7 - 10 mins to record which cylinders peaked and at what temps. This is a standard injector balancing test per Precision Airmotive. It is suppose to reveal what cylinders need different restrictors to slightly change the fuel to that cylinder allow all cylinders to peak all at the same time for LOP operations.

What is disturbing to me is that the standard white "Tefzel" coated aircraft wire in the same wire loom (running under the intake / exhaust outlets) were just fine. Even the zip ties were unaffected by the same heat level. The outer casing of the LSE supplied wire says 125C (257 degrees F). The white Mil Spec wire (rated at 150C / 302F) was unaffected. I ran a "all but scientific" test by heating the two wires next to each other with surprising results.

See pictures at this web page: http://geicodevelopment.com/light_speed_engineering

After I talked with an EAA Tech Counselor / Avionics Tech that works at Duncan Aviation, Lincoln, NE it was his professional opinion that this wire should not be in an aircraft firewall forward application.

Possible Corrective Action;
1. A heat shield around the wire under the exhaust.
2. Replacing the wire in the firewall area with rated aircraft wire.

Understand why I am posting this. I'm not associated in anyway with any EI. I'm not bashing anyone, any product, or anyone that using any product. In my world, when I find a potential problem like this I let people know ASAP, and you don‘t keep quiet. I’m not an engineer, I’m not an avionics tech. I would hope the VAF techies could address what I have found. Lets see if it’s a problem and what we can do to keep people safe if it is a problem.

 

[flion]

That looks like the input wires from the crank sensor? If it is, I decided to route mine around the engine instead of under it, to avoid crossing the spark wires or going near the alternator or starter cables - which the installation guide said to stay at least .5" from. The hottest area should be near the rocker covers, so I will keep an eye on it and take corrective action if necessary. Thanks for the heads up.

 

[Geico266]

I have received an e-mail from LSE confirming the wire used in the LSE Ignition crankshaft position sensor is not aircraft rated and should not be near any other wires.

IMHO this wire should not be used in an aircraft and specifically a firewall forward application.

 

[szicree]

I gotta say I'm pretty disappointed that they couldn't find a more suitable wire for such a mission-critical part. Now I gotta figure out how to address the problem. Drat!

 

[Geico266]

I was hoping one of the VAF engineering types could recommend wire that would be more suitable for the intended application.

 

[LifeofReiley]

I've got to say... there's too many installs out there without this issue. Something caused this problem but IMHO it had to do with the install.

 

[az_gila]

Markings

I was hoping one of the VAF engineering types could recommend wire that would be more suitable for the intended application.

Larry... what are the markings on the LSE wire? gil A

 

[Geico266]

I've got to say... there's too many installs out there without this issue. Something caused this problem but IMHO it had to do with the install.

I totally agree, but the install worked for 200 hours. When I ran a standard high egt test for 7-10 mins the wire case melted. LSE then confirms this is not aircraft wire. It's experimental so we can use what ever wire we want, but if I was able to melt the case in such a short time, everyone using this wire should at the very lease look at their install right away and put it on the list of things to look at every oil change.

If this wire is not rated for it's intended use (and there has been one "failure"*) then am I wrong in thinking heat / vibration / abrasion could be cumulative causing more failures down the road? *The LSE unit kept working and did not "fail", what I mean by "failure" is the wire case melted. It is not "Tefzel".

Personally, I have no problem at all running automotive / experimental components on my -3, or a 2 seater. I started flying ultralights. But the -10 is for carrying my family. No experimental components for me in this application. I'm just bringing this up so everyone using this wire is aware of what I found, that's all. LSE is a good product, but if I kept quiet about this wire, another VAF squardon member may have had a different "failure", and I would not be able to live with myself. We have had enough "incidents" lately.

JMHO.

 

[Geico266]

Larry... what are the markings on the LSE wire? gil A

E73175 24 AWG CL2P 125C (UL) CSA LL37586 CMP FT6/FT4 012034 FT

It's pretty hard to read, but this is the best I could see.

It is considered "plenum wire" . For use with computers, speaker wire, tele-communication in buildings.

 

[osxuser]

I started flying ultralights. But the -10 is for carrying my family. No experimental components for me in this application. ...

JMHO.

Not to point out the obvious, but maybe if you don't want experimental components you should switch back to mags? Or buy a certified airplane. All I know is wire isn't even certified to start with, it's a "standard" component.

While I'm sure the wire isn't rated to the temperatures in the engine compartment, note that "aircraft" wire doesn't really exsist. Most people use MS spec Tefzel, but there are a LOT of certified aircraft out there that have wire with vinyl insulation somewhere. Some A&P got lazy, or some other approved kit came with it. It's kinda like switches, the FAA just says 'industry standard electrical components' can be used, so I've seen some pretty wacky setups before.

Since we are here for a reason (dreaming, building, or flying RV's) maybe have a bit more consideration when you imply that for some reason certified components or kits are better, usually they aren't. I've seen the LSE installs, and they are very high quality kits, comparable to certified kits i've seen. So flawed though they may be, certified stuff isn't always better.

Comments like the quote above are fodder for lawyers.

 

[Geico266]

Not to point out the obvious, but maybe if you don't want experimental components you should switch back to mags?

Already done.

Since we are here for a reason (dreaming, building, or flying RV's) maybe have a bit more consideration when you imply that for some reason certified components or kits are better, usually they aren't.

I'm not implying anything. I'm just letting VAF know what happened in my application, and what I was told in my communication with the factory.

Comments like the quote above are fodder for lawyers.

So you would rather I said nothing and risk someone getting hurt? I'm just letting VAF know what happened in my application, and I want everyone one who has LSE to check theirs.