pertronix amd mallory coil 9-29701 voltage issue on Volt gauge

V/P 430b 4.3gl v6 carb

Ok boat running ok, no issue at all, but my reason for this thread is this.

Turning ignition to position 2 my dash volt dial shows 10v, but 12.7 v at battery terminal, and 12.7 volts at position 1 on ign switch, but as soon as the coil is energized the dial drops, if i remove the coil wires my battery volts dial shows 12.7v, i have fitted a pertronix spark module, the coil is a Mallory 9-29701 with built in resistor, both parts were imported to the uk via light house marine, and was advised the coil should be matched to the spark module. No ballast resistor is installed on engine loom, (removed by me upon install). I have also read that the spark module should not be connect to the + terminal on the coil, due to the voltage drop before cranking, the module requires 12, not the coil voltage at 10v.so a new 12 wire would have to be supplied direct to the module + terminal vi a supply from the ignition, but my ignition volts is reduced when the coil is connected?????

So is there a fault because i would like the Volt dial to show the correct voltage, when the engine is running the dials shows about 13.7 volts.

any ideas

I'm a bit stumped

mark

Mark, you are correct if you removed the ballast resistor, but ONLY if the ignition coil is internally resisted.
The coil is what determines whether or not the circuit is to be full 12v, or resisted voltage.

Double check this, but in either event I believe that the module would then require a full 12 volts.

Normally we will see a voltage drop during Cranking due to the heavy load of the starter motor.

The Pertronix is Hall Effect, so be prepared for some possible magnetic unit to sensor alignment issues.

A possible reason why you are seeing a voltage drop, may be that the Ignition Circuit itself is too light.
I would not necessarily circumvent this system, and I'd first look at my wiring harness for any continuity issues.
Perhaps there is an issue with the engine harness to hull harness interface connection.
Check this by pulling it apart and taking a look for any corrosion, etc.
There may be another harness connector somewhere in the system as well.... possibly near the helm.

Take a VOM reading directly at the rear of the helm volt meter and compare this to a direct battery bank reading.
The direct battery bank reading will be the more important reading.

Perhaps also compare your 13.7v charging voltage reading (helm gauge) with an actual VOM reading directly at the battery bank.
When first fired up, you'll see more like 14+ volts for a short duration.

The helm volt meters are not always accurate, in fact, these are almost always inaccurate.


If the engine runs well, and if the coil does not over-heat, you likely do not have an issue.... just a helm gauge that does not read accurately.

.

Rick, I think he is pointing out that when the coil is connected he reads 10v at the helm. And when he disconnects the coil he gets battery voltage at the helm.

Chris...... Agreed!
That's why I suggested taking a look at his engine harness/helm harness interface.
His OEM ignition circuit should certainly handle the current for the ignition coil.
Plus, he's using his helm volt meter for this reading!
Me thinks he should be using a real VOM!

What say yee?

Thanks for reply, i use a a base reading from a fluke dvm calibrated from my work, so i can trust its readings. the Mallory coil has a built in resistor, just recheck online.

As previously said digital volt meter connected to back of Volt gauge shows a reading of 10v once the coil is removed from the wiring harness, my 12v returns back to all the dials and the ignition circuit (purple wire that runs down the boat) 12v at the red wire on ignition switch 10v if coil is wired, if i place the coil back in to the harness, my volts drop back down to 9.79 up to 10.2. have checked all the harness connections all look good and bright, i check all the earth connections late last night and connections on alternator, constant 12 on back of alternator, earths good as well, fuse board checked ok and reads a constant 12v. but as soon as i connect the purple ignition wire that runs down the boat to the coil, it drops to 10v. i have many hours tracing this issue and it always comes back to the coil, my Garmin fish finder that has a battery volts reading on it shows bang on the dvm voltage reading, but the Garmin has its own 12v supply direct from the battery, Battery was recently tested at a battery center and it has alot of powerful juice in it.

The engine starts on a dim no choke, perfect starting, runs like a dream on the water, im just concerned of the issue that possible could cause an electrical fire.

been doing some more work and may of found the problem area, i decided to make a new loom direct from the battery to the + on the ignition coil and a - wire from battery to fuse box terminal with coil connected i get 12.06 at dvm and volt dial. so i removed the - negative feed from the battery test loom and 12.06 remains on dvm, so then i removed the + positive test loom wire from battery and the volts dropped straight down to 10.01 reconnected wire and back up to 12.06. reconnected the -test loom wire and no improvement.

So am i right in thinking that the fault lies with the positive supply wire from the engine loom to the fuse box???

mark,

(getting there at last this has bothered me for months)

Again, I'd not circumvent any OEM routing!
However, this is not to say that you may want to replace a wire or two in the OEM harness........ just leave them routed as per OEM.
IOW, remove what you are replacing.... and replace in the same location!
I know... I know...... easier said than done!

You/we can certainly circumvent any circuits that we want to, but when we do, we usually end up with a weird and unorthodox scenario.
Your call!

ok i understand the routing thing but how can i dismantle the main big black engine loom to helm connector as it rubberized and designed not to come apart.

other than ordering a complete replacement mail and female with connections.

thanks for your help thou recardomarine and Docksidemarineservices much appreciated, if i was close by i would buy you both a drink, but may take me a lttle while to get over to you.:rolleyes:

Yes, I know that it wouldn't be easy to get into that connector.
Have you pulled them all apart and checked them yet?
Like said, there may be one up near the helm also.

As for that drink...... what say we meet in Jersey Shore and ask Chris to buy the drinks?

Chris can buy the drinks then,lol

Have already taken the main harness loom connector apart all pins good and cleaned with braso metal cleaner, i had the engine harness completely out recently and cleaned and checked all connections and then braided the loom wires to protect them nothing found . the only thing i can think off is the nut and thread were the main supply wire is connected to the fuse board main terminal. unless there is another terminal connector hidden that i have not seen yet, will have another look tonight.

mark

Now going mad i swear it, this fault is driving me crazy.
well been out tonight for another 3 hours found & cleaned up all connections on the 12v rail from engine to helm, with coil and sprk module removed 12.5v is found on all gauges and back to the ignition wires to the coil. Good

Connected coil only and switched ignition on and yep 12.5v on all gauges and ignition wire down to coil purple and black wire.
connected coil and spark module and i now have only 9.97v and gauges not working correctly due to the lack of volts. disconnected module and 12.5v back on.

So i completed an amperage test and this is what was found, ignition key turned to position 2 on all three test
coil and module 10.02v on dvm amps drw 6.80amp
coil only connected 12.5v on dvm amp drw 2.71amp
spark module only 12.5v on dvm amps drw 2.79amp

so am i going mad or is that very high amps for a coil and module. if i reconnect coil and module but give the + side wire of the module another 12v feed from the engine all gauges work and volts stay at 12.5. so have i got a very power hungry coil or is there a possible short somewhere

Recardomarine please help my head is at breaking point i have no idea what is causing the problem
back to work for 12 hours in morning. so will reply later

mark

fault sorted at last,
turned out to be a high resistant red cable from the fuse board to the ignition key switch barrel, replaced just the red crimp terminals even thou not dirty just dull looking, fault now gone at last 12v returns to my dash and dials lights and coils. also took apart and cleaned fuse box terminals.

mark

Speaking of electrical problems... http://72land-n-sea.********.com/2011/08/believe-it-or-not.html

Sorry - the link doesn't work...here's the blog entry I did some time back.

Tonight I was going to do some plumbing work on my boat, Big Duck, in preparation for the Labor Day Weekend outing, but the mosquitoes were so bad I decided to work in the shop. While in there working I heard a subdued 'pop' and then a grumble. I thought it was my 40 year old air compressor pumping back up, but as the noise continued I realised that wasn't it.The loaping growl became ever so familiar, but I just couldn't place it.

Holy ****! that's Big Duck coming alive on her own!

I dashed out of the shop (it's not far to the boat) and up on the deck, noticing the exhaust flap vibrating as I went. Then on to the helm where I noticed the red light -signaling that the outdrive wasn't fully down, was on. I grabbed the key, only to find it was in the off position. I then dashed back and turned the main battery switch to off. The mill then went to sleep. Tomorrow I'll need to see if the impeller is still good and whether or not I blew the diodes in the alternator, then try to figure what kind of gremlins started up the motor in Big Duck.

If this had happened when I wasn't around, the engine would have overheated and been toast, so I'm assuming it's a sign that she's really anxious to get out there and go.

Can anyone explain this spontaneous ignition? There was no obvious starter cranking, I would have immediately recognized that sound.

She didn't light up again on her own when I turned the battery back on after the incident, and she properly responded to a brief key on/start. Suzy reminded me that The Duck should have run the blower for 5 minutes before she lit herself up.

I'll let you know what I found in another post.

Question one, was the engine running ie tacho running.

For engine to start up there would have to be a electrical short circuit some were on the starting circuit, i would start by checking relays and continuty checking with a dvm all cables, also check your ignition switch, if your kill switch was activated ie ignition isolated from starting, then the short would of happend on the engine loom side., may be a starter solinod fault, check all cables and connections around this area, also check all your earths.

If your engine was not running but tried to started you could of had a bit of unburnt fuel in the cyclinders or intake manifold and a short accured, this would turn the engine over briefly, and the only way the engine would continue to run is if the diode back in your alternator was faulty, this would cause a back EMF voltage to be returned back to the coil and contiune to run the engine. (This fault i have had recently)

hope this may help.

mark

Mark - you think like I do.


With the key out of the ignition I put a voltmeter on the coil and switched her from 'off' to #1 battery - nothing. I turned the key to light her up and she was running before I could release the key. This would have explained why I never heard the starter - it could have hit just for a fraction of a second.

She was pumping cooling water as she ran, so I goosed her momentarily to energize the alternator. The needle jumped right up to just a little under 14v. So, evidently no damage by her coming alive on her own and me switching the battery off while she was running.

I let her warm up a little. While I was peering into the engine compartment, looking for clues, the starter engaged on it's own, trying to start the running engine. I disengaged the starter by switching the batteries to 'off' but the motor kept running. When I turned the key off, she went silent. I lit her up again and got the same results.

I went up and examined the keyless ignition switch on the flybridge. It was very warm to the touch. Suspecting some of the recent heavy rain got into the works, I removed the switch and took it to the bench to check for conductivity; the ohm meter showed resistance, telling me the circuits were not completely open. Apparently with the ability to pass a slight current, the sizzling and cooking going on at the contacts would occasionally incite full juice to pass.

With the flybridge switch disconnected, I again lit her up and let her run for a spell. She appears to be happy now, pumping cooling water, charging the batteries and not trying to start on her own. When I rewire the new flybridge switch, I'll put in a separate starter button - to keep the ignition and starting circuits isolated.

realy good to hear you sorted it out, that is one peperd switch, last thing you need is the engine starting on it own when people are around the boat swimming.

That is one large boat to trailer, great pic, let us know how you got on

markw

Proof positive that ignition switches should occasionally be replaced!

BTW, that hole in the ignition switch should allow for an occasional blast of corrosion blocker of some sort.