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SureFly P-Lead Fuse Blown

M

moshelichtman

I'm New Here
Looking for SureFly experts. My RV-6 with an IO-360 has a SureFly on the left and a standard mag on the right. After an uneventful mag check and some 10 minutes idling before takeoff due to heavy traffic, the engine started backfiring and running very rough. When we removed the cowling, found the in-line fuse of the SureFly P-Lead blown. I've been flying with this SureFly for several good years with nil issues.

Any idea what may be the cause for the fuse blowing like this?

Thanks,
Moshe
 
First thing I would do is to check the power wire from the fuse to the Sure Fly SIM module. If no fault was found, replace the fuse ONCE.
If the new fuse blows after it has been replaced call Sure Fly.
If the new fuse does not blow, check green LED ON @ cyl 1 @ 0 deg.
Start the engine.
If the fuse has not blown AND no green LED call Sure Fly.

If the Sure Fly SIM module has failed, it will not be possible to start the engine
because it is a standard mag timed @ 25 deg.

Contact SureFly customer support
817-373-5161

Good luck
 
Avanza said:
First thing I would do is to check the power wire from the fuse to the Sure Fly SIM module. If no fault was found, replace the fuse ONCE.
If the new fuse blows after it has been replaced call Sure Fly.
If the new fuse does not blow, check green LED ON @ cyl 1 @ 0 deg.
Start the engine.
If the fuse has not blown AND no green LED call Sure Fly.

If the Sure Fly SIM module has failed, it will not be possible to start the engine
because it is a standard mag timed @ 25 deg.

Contact SureFly customer support
817-373-5161

Good luck
Click to expand...
Thanks. Good suggestions.
 
Richard Connell said:
I assume you mean the surefly power supply and you don’t have a fuse in the P-lead?
Click to expand...
Yes, sorry. My suspicion is that the fuse blew when the mechanic on the field I'm in (not my home field) connected an external battery and tried some things on the SureFly. Before going to the shop, I tried both mags and only cylinder 2 was cold on the SureFly which leads me to believe the fuse is not the issue.. It's either a spark plug, harness or the SureFly...
 
If you have a cold cylinder I would check the exhaust valve.
A stuck exhaustvalve may be the problem.

Good luck
 
Avanza said:
If you have a cold cylinder I would check the exhaust valve.
A stuck exhaustvalve may be the problem.

Good luck
Click to expand...

Thanks again. So we followed all your suggestions and the Engine runs and all cylinders are firing on the SureFly but drop during mag check is 130 at 1700 RPM, vs 100 for the standard mag. The mechanic commented on the timing which is set to SF's standard 25 while my IO-360 plate says 22. Can this advanced timing be the reason for the larger drop? Shouldn't the SF drop be much smaller then the standard mag? Thanks
 
On my IO-360 I have a very even 60 RPM drop from both the left magneto and the right SIM so I would have thought your 130 RPM drop was excessive.

To make your troubleshooting easier I recommend that you ensure that your standard magneto is timed to the angle stated on the dataplate and that your Surefly dipswitches are also set to the same angle. In reality, whether the angle you set them up to is 20 degrees, 22 degrees or 25 degrees won't really matter for the purposes of getting the troubleshooting sorted out, so long as they're both the same. Remember that the SIM is timed to 0 degrees and the dipswitches determine the operating firing angle.

All of that said, the smoothness of the single ignition source shouldn't be drastically affected by a couple of degrees of timing. Clearly a large difference from the recommended timing angle will make a difference but having them at 20 degrees instead of 22 degrees won't make much of a difference. If the engine is running rough with one system isolated then I would be looking at the harness and the plugs first.

How many hours on the magneto?

My engine is set to 25 degrees with fixed timing at present and its running well.
 
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moshelichtman said:
Thanks again. So we followed all your suggestions and the Engine runs and all cylinders are firing on the SureFly but drop during mag check is 130 at 1700 RPM, vs 100 for the standard mag. The mechanic commented on the timing which is set to SF's standard 25 while my IO-360 plate says 22. Can this advanced timing be the reason for the larger drop? Shouldn't the SF drop be much smaller then the standard mag? Thanks
Click to expand...

Do you have high compression pistons? They often recommend 22 or 23 degrees base timing. My 9.5 to one engine recommends 23.
 
moshelichtman said:
Thanks again. So we followed all your suggestions and the Engine runs and all cylinders are firing on the SureFly but drop during mag check is 130 at 1700 RPM, vs 100 for the standard mag. The mechanic commented on the timing which is set to SF's standard 25 while my IO-360 plate says 22. Can this advanced timing be the reason for the larger drop? Shouldn't the SF drop be much smaller then the standard mag? Thanks
Click to expand...

RPM drop is directly related to advance, not ignition style, assuming all 8 plugs are firing. Two ignition systems with the EXACT same timing will have fundamentally equal RPM drops. If the advances are different, the one running with the greater advance will show less of an RPM drop when the lesser is turned off than vice versa. Up to optimum advance, more advance = higher RPM.
 
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planenutz said:
If the engine is running rough with one system isolated then I would be looking at the harness and the plugs first.

How many hours on the magneto?

My engine is set to 25 degrees with fixed timing at present and its running well.
Click to expand...

We dialed back the timing closer to the engine plate's stated 22 and resynced the SureFly. The drop went down to approx 90-100 RPM. The engine is new rebuild from Aerosport, installed approximately 30 hours ago. I did the break-in by the book but it's still consuming a lot of oil and when we removed the plugs all but one were wet. When the engine is cold the mag drop is as stated above and the engine stays smooth on one mag, but when it's hot and I have a long taxi prior to the mag check it runs rough. Is it possible that the roughness is due to the plugs getting covered with oil that's not getting burned off due to the low RPM? I plan to do a LOP mag check at altitude tomorrow to see if I see this roughness at higher RPM and in the air. During a normal cruise - the engine is running smoothly ROP and LOP.

Also - wondering if it makes any sense for the break-in to take so long assuming the break-in was done by the book (high MP, high power)? we scoped the cylinders after approx 25 hours and wall scoring is good, no glazing - so why are the rings not getting seated still?

To your question about the mag, it has approximately 220 hours since we installed new points in it. Haven't opened it since then.
 
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If the engine runs rough after a long taxi I would look at the fuel lines.
Fire sleeve on fuel line ? Air cooling on fuel pump ?

Good luck
 
Walt said:
People say this all the time, fact is if your idle mixture is adjusted correctly there is little benefit to leaning on the ground.
Click to expand...

Walt:

I respect your option and value most of the items you have commented on. This is the first post that I have seen you make that I really have a problem with.

IF the idle mixture is set correctly at sea level on a standard day, I may agree with your statement as long as at sea level and standard temperature. Having lived and flown in the Southwest more than any other part of the country, I disagree.

When at a higher elevation than sea level, the idle mixture will not be correct. When temperature is higher than standard, the idle mixture will again be too rich.

At low power, ground operations, I lean as much as possible that the engine still runs smoothly. For the most part in a hot environment on the ground, I have the electric boost pump also on.
 
RV6_flyer said:
Walt:

I respect your option and value most of the items you have commented on. This is the first post that I have seen you make that I really have a problem with.

IF the idle mixture is set correctly at sea level on a standard day, I may agree with your statement as long as at sea level and standard temperature. Having lived and flown in the Southwest more than any other part of the country, I disagree.

When at a higher elevation than sea level, the idle mixture will not be correct. When temperature is higher than standard, the idle mixture will again be too rich.

At low power, ground operations, I lean as much as possible that the engine still runs smoothly. For the most part in a hot environment on the ground, I have the electric boost pump also on.
Click to expand...
You're 100% correct Gary, been a land lubber so long I tend to overlook what folks at higher altitudes may experience. At SL temperatures do have some bearing on mixture, but very little IMO unless there is a large temperature swing.
 
airguy said:
You mean aside from fouling the spark plugs?
Click to expand...

"Assuming" we are not talking about the altitude variation Gary mentioned above, a properly set idle mixture will not lead foul plugs.

It does seem to me that many folks either don't know how to set idle mixture (includes A&P's) or just don't bother with it, either way I find so many that appear to have never been adjusted correctly that is why most people have to lean on the ground.

I just had a FI system OH'd for a customer, came back way out of wack, I spent probably close to an hour getting it dialed in, and got a lot of exercise at the same time getting in/out of the aircraft probably 10 times at least.

The good news is the customer was ecstatic at how well the engine ran both on the ground and in the air. (hint: the below from AFP should be followed)

"Regardless of time in service, overhaul is recommended based on an accumulated calendar time of 12 years for fuel control units and 8 years for flow dividers. This is from the date of manufacture or last overhaul date."
 
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