Ignition Problems. Help??

[J12345T]

Klaus replied that the A and B channels are independent because they need to fire 180 degrees out of phase with each other.

Thx again Andy,

We ran a further test to check the function of the mini sensor. With a breakout chord connected between the input plug and the box we rotated the flywheel around and measured the voltage across the various parts of the plug. The lower sensor's A channel dropped from 5v to (virtually) zero at the appropriate time. The B channel's voltage didn't change throughout the entire rotational cycle.

We also checked the spark generated by the coils and when on the R side the appropriate coil did not fire either (which stands to reason).

Given that we had previously swapped the L box for the R box and the problem remained on the R side that really confirms an input (rather than output) problem and the above test would pretty much confirm a problem with the lower sensor B channel (sensor or wiring). Rather than spend many more dollars fault finding I've ordered a replacement sensor from Cub Crafters USD250.

I truly hope this solves the problem. I think it will but it has been a crafty gremlin so who knows..

Cheers,

James.

[Andy]

The lower sensor's A channel dropped from 5v to (virtually) zero at the appropriate time. The B channel's voltage didn't change throughout the entire rotational cycle.

Glad you have that test data. It seems conclusive to me.

In a follow up email Klaus re-stated what I thought I had read previously - "The sensors don't fail".

If the new sensor fixes the problem I hope the failed one will go back to LSE for analysis and that you'll get a report that you can share.

[J12345T]

Glad you have that test data. It seems conclusive to me.

In a follow up email Klaus re-stated what I thought I had read previously - "The sensors don't fail".

If the new sensor fixes the problem I hope the failed one will go back to LSE for analysis and that you'll get a report that you can share.

Hi Andy,

Yes, Klaus was very insistent that the sensors don't fail and given that he is the expert I don't know what to make of the evidence I have been seeing. Maybe it is the wiring to the sensor but that can't be field repaired as far as I can see so a new sensor it is...

I will certainly report the results when I get the parts (in a week or so) and get them fitted.

Cheers,

James.

P.S. The only other thing I can think of is that maybe one of the 4 magnets has lost it's magnetism??

[StanleyMedic]

Hi All,

The engine is running like a bag of bolts when selected to the R side ignition system. Engine runs fine on L and seems OK on Both.

The problem is somewhat intermittent in that a flight in the morning displayed the problems and I couldn't fly whilst the (trouble shooting) flight in the afternoon was fine. A couple of weeks later same problem.

Aircraft is now with the maintenance provider looking for the problem/ solution. So far we've removed the cowls, checked the plugs, swapped the plugs, checked the coil harnesses, checked the coil wiring resistance, checked the timing sensors. Only issue found was that those crappy spade terminals on the coils were a bit lose. They were 'tightened' but the problem remains.

I should also say there is no engine monitor of any description fitted (yes I know).

We're going to change out the spade terminals for something more aviation appropriate but that is a long shot.

Can anyone tell me which coil controls which spark plugs by any chance as they're not marked at all...

Any other suggestions much appreciated.

Cheers,

James.

I would bet on the spade connectors. If you knew which cylinders were running cold, I could tell you where to look. The automotive connectors are sketchy. Some guys solder the wires on directly but the soldering iron heat is less than ideal.

[J12345T]

I would bet on the spade connectors. If you knew which cylinders were running cold, I could tell you where to look. The automotive connectors are sketchy. Some guys solder the wires on directly but the soldering iron heat is less than ideal.

Hi All,

Re the spade connectors. I thought so too as those things should not be on any aircraft let alone on the ignition system; but not so. The problem was definitely a failed B channel on the lower crank sensor; ie. the sensor that never fails...

So the new sensor arrived yesterday from CC and was promptly fitted. The short version of the story is that everything now works perfectly and it seems to be running reliably and sweetly. FWIW the new sensor was $25 cheaper ordering directly from CC rather than from Lightspeed and came with the correct cable length etc.

So a very tricky gremlin seems to have been sorted. All I can say is that we had to become local experts in this system in order to identify the fault and rectify it. This was very frustrating, as apart from the help on this forum we received precious little helpful advice from those who should have been providing it; but I'll leave it at that. So a big thank you to the participants in this thread :-)

As for the removed sensor; I'll ultimately leave that up to the owner however, I'm not sure there is much value in returning it to the manufacturer for inspection.

Cheers.

James.

[Andy]

As for the removed sensor; I'll ultimately leave that up to the owner however, I'm not sure there is much value in returning it to the manufacturer for inspection.

Glad you have it working properly again! If there is no other use for the sensor I'd like to take a look at it.

Andy

[flyfisherofmen]

Glad you have it working properly again! If there is no other use for the sensor I'd like to take a look at it.

Andy

I have the exact same issue and spent all weekend swapping coils, checking the LSE ignition boxes by swapping, checked plug wires and re-did spade connnector. I'm hoping the sensor is the issue as it was the right only on cylinders 1 and 2 (Channel B) same as was stated. I'll be calling in an order for a new sensor Monday.