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  #1   IP: 70.51.181.13
Old 07-02-2008, 01:51 AM
Ken Mason Ken Mason is offline
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Continuing Coil Problems

Since neither I nor anyone on the forum have been able to find the cause of my problem I am looking for advice on a work around.

Problem: After running for random amounts of time, at random rpms, on random loads, the engine (Atomic 4) will die and will not restart. Switching over to another coil immediately solves the problem. The problem existed before and since the installation of electronic ignition. All the coils used pass the higher amp test and are oil filled. After cooling down the coil that died will work again. The leads are all new.

Workaround: I want to be able to mount 2 coils and as required switch back and forth between them. Obviously switching the positive and negative leads is easy but what type of switch is used for the center lead? Also are there length restrictions on the various wires as this will determine where the dwitch will be located.
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  #2   IP: 38.102.16.123
Old 07-02-2008, 08:29 AM
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This doesn't answer your question, but have you considered mounting the coil on a bulkhead, to help keep the temperature down?

Do you by chance have electronic ignition?

Bill
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  #3   IP: 70.51.177.171
Old 07-02-2008, 10:08 AM
Ken Mason Ken Mason is offline
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Hi Bill
I fully understand that my trying a work around is not fixing the problem but I am tired of having guests on the boat, and watching their look of panic as the motor dies and I have to delve into the engine compartment to swith coils <grin>. It happened again last night.

No I have not tried moving the coil to a bulkhead and certainly will do that. Yes I have elsctronic ignition. But the problem happened before that was installed and continues to happen after.

What makes diagnosing it difficult is that It is so random. Yesterday was a 1 hour run in calm water at 2/3 throttle, then a 6 hour shutdown, then a 20 minute run at 1/4 throttle in calm water, then 5 minutes idling in neutral, then the coil failed.

Thanks for your response
Ken
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  #4   IP: 138.88.162.86
Old 07-02-2008, 10:37 AM
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I used to chase electrical gremlins all the time in my old truck and rewiring it was the best thing I ever did. The weirdest things would happen and drive owners (of old Scouts) crazy. Old boats are often wired as poorly as old trucks.
Because your problem is unpredictable, I would check everything carrying a current. I would start with new coil wires. and work back from there. I'd investigate can cause the coils to overheat.
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  #5   IP: 70.49.62.36
Old 07-02-2008, 01:25 PM
Ken Mason Ken Mason is offline
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Hi,
Thanks for the response.
The center wire connecting the coil to the distributor is new. It was changed along with the plug leads when electronic ignition was installed last summer. I did discover a posting that talked about the small black wire that connects one of the pole sof the coil to the distributor and I will change that one.

I apologize but I did not understand this line: "I'd investigate can cause the coils to overheat. "

Regards
Ken
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  #6   IP: 38.102.16.123
Old 07-02-2008, 02:20 PM
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Don Moyer Don Moyer is offline
 
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Ken,

You may have fallen victim to the "Elephant Syndrome". This phenomenon relates to a gentleman standing on a street corner snapping his fingers. A passerby asks why he's doing that, and he replies that he's keeping elephants away by snapping his fingers, whereupon the passerby states the obvious, which is that no elephants have ever been seen around this neighborhood. To that news, the finger snapper replies: "I know, see how great it works."

In your situation, if there is something else behaving like a failing coil, then changing coils isn't doing much more than snapping your fingers. In that case, there is a good possibility that the engine was going to start anyway when something else cooled down even if you didn't change coils.

There is at least one other item that behaves in this manner (fails from heat and cures itself when it cools), which is a faulty connection in the primary ignition circuit (some electricians call these faulty connections cold joints, I suspect because they only work when they're cold).

Please skip this paragraph if this is more than you wanted to know, but I am told by normally reliable experts that an electrical circuit sees a weak connection on the verge of failure as a localized zone of high resistance which translates into a small amount of heat build-up. As the heat builds up, the expansion created by the heat eventually causes the connection to open up (minuscule though this heat and expansion is, remember that a connection in this condition is on the virtual edge of failing anyway, even without the heat and expansion).

To keep things simple, before chasing the entire primary circuit which runs from the large battery terminal on the starter solenoid, through the ignition switch and back to the positive terminal of the coil, you could simply connect a jumper wire from the large battery terminal on the starter solenoid to the positive terminal of the coil. If the engine never shuts down as long as that jumper wire is installed, you will have confirmed that the primary ignition circuit is a cold joint in it someplace.

If the shutdowns continue with the jumper wire installed, you can check the remaining short section of the primary circuit which is between the negative terminal of the coil and the points. Sometimes the conductor in this short wire develops a cold joint where is passes under the distributor cap or at the terminal of the coil or at the points themselves.

IMPORTANT NOTE: Installing the jumper wire between the starter solenoid and the coil is the very same thing as turning on the ignition switch, so you cannot leave that wire installed except when running the engine or you willburn out the coil or kill the batteries.

Don
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  #7   IP: 70.51.181.244
Old 07-02-2008, 03:37 PM
Ken Mason Ken Mason is offline
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Hi Don,
Thank you for the response.

I understand your analogy about snapping fingers and elephants but I am sure it does not apply to this situation.

The first 2 times this problem happened there was a delay of at least half an hour and the coil was not changed and the engine restarted. However starting with the third time, every time including last night, the coil swap has taken place immediately that the engine stops. As soon as the "new" coil is connected the engine starts. So there is no significant time for anything to cool down. Please note that I am basically cycling through the same three coils.

The responses from you and the other posters are greatly appreciated and I will try any and all suggestions. However my original post requested help with building a switch arrangement. I plan on leaving on a cruise in August that will as usual take me through the St Lawrence Seaway and it locks. I do not want to run the risk of having to change the coil in the middle of a lock or a little upstream from a dam. I will continue to try all suggestions but I want a plan "B"

Thanks again for the post
Ken
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  #8   IP: 69.140.7.29
Old 07-02-2008, 11:03 PM
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msauntry msauntry is offline
 
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Sorry, left out a word there.
Meant to say:
"I'd investigate what can cause a coil to overheat."
Why are they struggling to operate?

Ken's other post reminded me that there is a fault peculiar to GM style starters, which A4's have. Google "GM hot start problem" and you can see if that fits your symptoms. The solenoid and starter absorb all that engine heat and resistance builds up so much that it won't start after its been running fine. A remote solenoid fixes that problem. I suffered from this for quite a while before figuring it out.

I imagine to wire up a second coil, just run wires from the source of the first coil's wiring, add a switch to the positive side, and when you need it just transfer the center distributor wire to the new coil and flip the switch.
I can't think of any way to avoid having to move the center wire, so you just gotta be quick and have the engine hatch off moving through the locks.
You will need another switch on the first coil to turn it "off".
Needless to say, test it out before the trip.

Good luck.
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Old 07-02-2008, 11:25 PM
sunnnnseeeker sunnnnseeeker is offline
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I had unexplained shut downs on my A4. While the engine was running I jiggled all the wires and switches and finally hit one that caused the engine to stop. Turned out I needed a new ignition switch.
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  #10   IP: 206.181.246.34
Old 07-03-2008, 09:45 AM
SEMIJim SEMIJim is offline
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Quote:
Originally Posted by Don Moyer View Post
There is at least one other item that behaves in this manner (fails from heat and cures itself when it cools), which is a faulty connection in the primary ignition circuit (some electricians call these faulty connections cold joints, I suspect because they only work when they're cold).
I suspect the term stems from soldering. When electrical connections are soldered (actually, when anything is soldered), failing to heat both the joint and the solder sufficiently results in a mechanically and electrically inferior bond known as a "cold solder joint."

Quote:
Originally Posted by Don Moyer View Post
... I am told by normally reliable experts that an electrical circuit sees a weak connection on the verge of failure as a localized zone of high resistance which translates into a small amount of heat build-up.
Both true, and not necessarily "small." Poor connections can start fires.

Quote:
Originally Posted by Don Moyer View Post
As the heat builds up, the expansion created by the heat eventually causes the connection to open up (minuscule though this heat and expansion is, remember that a connection in this condition is on the virtual edge of failing anyway, even without the heat and expansion).
The joint's erratic behaviour can also be provoked by vibration or any other movement, or, perversely, the phase of the moon .

Jim
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  #11   IP: 70.17.93.179
Old 07-03-2008, 11:07 AM
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msauntry msauntry is offline
 
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I'm still betting on a wiring problem somewhere. Coils going bad is the symptom, but what's causing it? I thought coils either work or they don't. But I guess there's more resiliency than I thought, if you can get bad ones working again.

An ignition switch is pretty exposed to corrosion and hard to see inside of, so it might be a likely source. Its also something you're jiggling each time this happens when you try to restart. If its old, just replace it and eliminate it as a potential source. In the grand scheme of things, they're not that expensive.
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  #12   IP: 70.52.1.241
Old 07-05-2008, 05:44 PM
Ken Mason Ken Mason is offline
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While discussing my problem with some sailing friends at, of all places, a funeral on Friday night we might have hit on the problem.

If we have it illustrates a problem far worse than Don's elephants, that of making assumptions and thus not questioning everything.

I had the alternator rebuilt last summer as soon as I got the boat to Montreal.
I installed it and never gave it a second thought. Today I started the engine, let it settle into an idle and then I metered the positive and negative poles of the coil. The voltage is fluctuating wildly between about 15 and 19 volts. Now I am the first to admit that much about electricity is a mystery to me, I know just enough to get into trouble but since one of the inputs to the coil is coming from the regulator on the alternator should this not be a steady 12v? If the coil is expecting 12 and receiving 15+ I am not surprised it is over heating. If anyone confirms my theory that it should be a steady 12v then I will pull the alternator and take it back to the shop.

Thanks again for everyone's interest and suggestions
Ken
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  #13   IP: 138.88.162.86
Old 07-07-2008, 12:08 PM
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The alternator output will fluctuate a little with RPMs, but your values seem too high. The right range should be 13.5-14.5.

That could explain why your coils are freaking out!

Get the alternator rechecked.
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  #14   IP: 71.217.31.227
Old 07-28-2008, 03:08 AM
JackConnick JackConnick is offline
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I have had he exact issue you described and finally figured out that I was running a coil rated for 10-12 volts for a car. Marine coils are rated at something like 12-15 volts. Rather than look at the coil, you might look at the brand/spec and go get one for a marine parts store or Don.

That being said, I am experiencing coil issues (see my thread) and I think it is heat/vibration related. Have you tried moving the coil away from the engine block? The AT4 mount is just plain silly, it boils those suckers!

As far as your alt output, that seems king of close, it's really a function of the voltage regulator and it's always going to kick in high and then taper off. Easy enough to have them check it out for you. Also easy to just pull the alternator and run it at the dock and see if the problem repeats.

I commiserate with you pal!

Jack

Last edited by JackConnick; 07-28-2008 at 03:10 AM.
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  #15   IP: 142.68.127.7
Old 07-28-2008, 05:17 PM
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rigspelt rigspelt is offline
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This thread brings to mind a frustrating tale I can tell that might even be relevant.

Don wrote: "I am told by normally reliable experts that an electrical circuit sees a weak connection on the verge of failure as a localized zone of high resistance which translates into a small amount of heat build-up. As the heat builds up, the expansion created by the heat eventually causes the connection to open up (minuscule though this heat and expansion is, remember that a connection in this condition is on the virtual edge of failing anyway, even without the heat and expansion)."

For about 3 years, the tach on previous boat would flicker after running a while. Then it would occasionally flicker and the engine would shut off, but infrequently. I could always restart the engine in about 20 minutes. Finally it started happening regularly. I spent well over a thousand dollars over two years chasing the problem, including chats with 4 good mechanics, replacing ignition parts including coils, cleaning the old tach, installling a new tach, rewiring ignition connections at the engine, rewiring the igntiion panel (which it needed, I discovered), etc, etc.

The problem was ridiculously simple and obvious in retrospect: Turned out to be a failing slave starter solenoid in the part of the solenoid wired to the coil - a $35 part. It failed exactly like the cold joint thing Don describes, and I got the same explanation from a marine electrical engineer. Another gremlin also vanished when we installed the new solenoid.

The moral for me: if there is a solenoid in a problem circuit, consider replacing it.
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