AOG - Battery/alternator/starter problem----solved :)

FIXED! See post below for the final resolution.
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Airplane On Ground.
Currently stuck in Elko, NV with weather AND maintenance problems. I don't think even VAF can help me with the weather, but maybe you can give me some ideas on my maintenance problem. Here's the narrative:
-Flew from Boulder City, NV to Burley, ID on Friday. 3 hrs, No problems.
-Flew local sortie on Saturday, about 0.8 hrs, no problems.
-Flew from Burley, ID to Elko, NV today. 1.5 hrs, no problems.
-Attempted to fly from Elko to Las Vegas, but turned back due to weather. Total flight time 2.5 hrs on that leg.
-After landing back at Elko and trying to fire up - the battery is dead! Or at least, something is wrong and the battery can't spin the engine. The local FBO tried charging the battery for me for about 1.5 hrs at 2-3 Amps. Tried it again, same problem - won't spin the prop. Acts like it's a dead battery when trying to crank, but otherwise still reading 12+ volts.
-The battery is a PC680 that I bought new in March at the Madera Formation Clinic (thanks Slick), so it's barely been used.
-The electric system showed about 13.3V the whole flight (my system loses about a volt to the sensor, so that should have been a charging voltage of about 14.2 at the battery).
-My ammeter reads current on the main alternator output wire. It showed pretty normal output/demand during the flight (about 15 amps) except for one oddity. At one point I showed a spike to a very high amperage (in the 40s). I've had odd ammeter readings before (in the 100's! and dropping offline) and have chocked it up to something with my sensor. Regardless, I turned off my strobes and nav lights to start shedding load, and the reading went back down to normal, so I just left that off for the remainder of the flight - figuring I'd troubleshoot it later. All was back to normal at that point.

So, if you've read this far - thanks - here's my question:
Is there a failure mode of anything else in the starting system (i.e. Skytec starter, starter solenoid, etc) that would look like a low-powered battery? I'm going to try charging up the battery again tomorrow morning and hopefully I can get out of here, but I'm worried it might be something else and I might have to troubleshoot. I'm going to try and check the resistance from the battery through to the starter as well to see if I have any kind of problem there.

Any ideas you have are appreciated,

Try checking the starter solenoid aka contactor.

After that, look for wiring issues and do not forget the ground path.

How many hours on the plane, how long (if ever) since replacement of the starter or starter solenoid??

Good luck..........

Starter/Solenoid = original

Airplane has been flying for 8 years (January 2006) and has 550 hrs. The starter is a Sky-Tech. Both the starter and solenoid are original - never been replaced.
The solenoid seems to work - the starter does engage and move the prop (a little bit).
I'll remember to check the ground path resistance back to the starter as well.

Thanks Mike!

The solenoid has a set of contact points in it that will eventually burn, and cause high resistance or just fail altogether.

This would be my first place to look based on what you have described.

Take a look at this thread.

http://www.vansairforce.com/community/showthread.php?t=90977

solenoid

Try shorting the start solenoid if possible. At least it will rule it out or confirm.

I have had the exact same problem in my Cherokee 180. Skytec light weight starters have an additional/redundant solenoid that is starter mounted. The contacts inside of the solenoid become pitted and burned and will cause such high resistance that it appears that the battery is failing due to shorted cells or loss of capacity. New solenoid from Skytec fixed it twice. After the second time I traded it in to the factory for an in-line model which has a much lower failure rate and is the best starter that I have ever used. Do you have the light weight starter?

hmmmm...

Mike, you may be on to something there. Conveniently, there is an Autozone across the street from the FBO if I need to replace the solenoid!

Mike Hammond,
Yup, SkyTech 149-12PM lightweight starter. Hopefully its just the solenoid. I really don't think its the battery at this point.

Unfortunately you cannot jump this solenoid due to the proximity to the propeller. Try and borrow a serviceable starter to get you home and then send the light weight in for repair, Skytec will give you credit for exchange towards a new or rebuilt in-line unit which may be the last starter you ever buy. If you chose to keep running the light weight unit I would recommend purchasing a spare solenoid from Skytec and keeping it in the plane.

I am not sure if the integral solenoid has an automotive application. You may want to call a skytec and let them know of your problem (they won't be surprised) and see if they can give you a automotive cross reference so that you can try and get a replacement locally.

One last idea! If you have a firewall mounted starter solenoid (some experimentals use the integral solenoid only) the you may be able to remove the power cable from the starter solenoid input terminal and relocate it to the output terminal that feeds the commutator. If there is room to do this you effectively are bypassing the integral solenoid and operate off of the airframe mounted solenoid only.

http://www.skytecair.com/Wiring_diag.htm

I've been just where you are, and I'd say the easy thing to T/S, and a very likely cause, is the firewall-mounted solenoid (as others have said). We confirmed this once in our case with a "U"-shaped piece of piano hinge pin as a jumper to jump around the solenoid (just hug the firewall, and keep the ignition off. Yes, you can probably source a replacement at the auto parts store.

Paul

I'll try to test/jump/replace the airframe-mounted solenoid first. Since it's never been replaced, it might be the culprit (like in Paul Dye's thread above). Thanks for the data, Mike!

Any starter shop should have the starter mounted solenoid, it is from a Ford geared starter and is used on many cars and trucks, very common and easy to replace

solenoid

Didn't I say this in post 5? Let us know what solves your problem, please.

one or two flips of the prop will get it going, in a pinch revert to simply. fix it when you get home.

swordtail said:

one or two flips of the prop will get it going, in a pinch revert to simply. fix it when you get home.

Click to expand...

It could also get you seriously hurt or killed. Hand proping an O-320 or O-360 is not even remotely close to hand starting a 65 HP Continental on a champ or a Cub. I know people attempt it all the time, some may even be successful, but I would rather fix the airplane than take the risk of being hurt or worse.

First replace the solenoid. I have had several skytec starters rebuilt at automotive shops. Except for the casting all the electrical parts are automotive.
Then I would take a serious look at your alternator. I have 800+ hours on my rocket and for the last year the starts have not been great. I replaced the battery and that did not solve the problem. The charging voltage was lower then the 14.2 it used to put out but since is was higher then the resting battery voltage I thought all was well. I replaced the alternator 25 hours ago and the whole system is working much better. The old alternator has been rebuilt, new internal voltage regulator, and is sitting on the shelf waiting for the next sign of voltage under 14.2V.

And the winner is...

Troubleshooting this morning, thinking probably a starter solenoid, but...

1. Oil temperature sensor dropped offline yesterday. Connection seems good to the engine monitor. That's weird.
2. Dropping the cowl - the right exhaust is hanging lower than normal. Hmmm, that's weird. Push it back up.
3. Get settled under the engine and start to work on the starter solenoid. My plan was to actually take the big output wire and just temporarily bolt it onto the "input", or "hot" side of the solenoid. That way, I can just flip the master switch for a second to test how the starter spins the prop. Figured it was just a bit slower and a bunch safer than shorting it while sitting under the engine (mine's not very accessible while standing).
4. Whilst doing that, noticed that something was amiss - see picture below:



Turns out the bolt holding the ground wire to the engine case had wiggled out. It's the same bolt that holds the right exhaust hanger (aha!). The grounding wire wasn't making contact anymore, thus my sudden starting problem (aha!). But the starter did turn a little bit, right? Where was all that amperage going? Well, the oil temperature sensor died when I was trying to turn the engine. I'm thinking at least some of those amps went through the sensor and fried it. No other noticeable consequences to my AF-2500 engine monitor, though - I'll keep an eye.
Bolted the ground wire back on and she fired right up.
Mike Starkey - you're the big winner - it was the ground path after all.
Thanks for all the suggestions, and I think I'll probably get a spare starter solenoid because I'll bet it's only a matter of time, and not much.

Big lesson learned: Use your noodle and don't jump to conclusions. Every indication in the airplane was that the battery and charging system were just fine, so look elsewhere. I almost let the local A&Ps get a little too aggressive on my battery (they really don't know much about AGM batteries like the PC680) and they could've damaged it. They certainly weren't helping troubleshoot the real problem.

Now if only the weather would clear up, I'd be on my way...

Great news

Jordan, glad you found the problem, and that it was cheap and easy to fix.

Thanks for the report back.

Mike, can you change the title of the thread so it doesn't look like I need help still?

JordanGrant said:

Mike, can you change the title of the thread so it doesn't look like I need help still?

Click to expand...

Sure, consider it done.

Glad it worked out OK. Gotta love it when a fix does not cost a few hundred dollars.

Great story with a good ending Jordan. It is so easy (happens to all of us) to zero in on a particular "solution" to a problem and miss other potential causes - glad you had an open mind and found the issue so easily.

Before airplanes and engines got complicated, gauges were all mechanical and analog, so the only wires running to the engine were the ground, starter cable, alternator wires, and mag P-Leads. If the ground path got disrupted, you usually ended up smoking the P-Leads when the starter curren tried to go back through them....

Paul

Me too!

I had that same bolt come out, but my ground wire does not go there.
I also put two grounds to my engine, just in case one come loose. One goes direct to the tree of tabs ground point and the other goes to a screw under the breather tube clamp.
Just throwing that out there, might be a good idea.

I'm a believer in two ground wires as well after this happened to me. In my case it destroyed a couple of control cables, can't remember if it was mixture or throttle or prop, but a good idea to check these at some point.