Another intermittent shut down issue

[Muntasel]

Ok guys, new Afourian here, I just read another recent post (by Solitaire) and I have an almost similar issue, so I will try some of the troubleshooting suggested there.

But here’s what I have:
Rebuilt A4 (2009) with upgrades: new fuel tank , indigo electric fuel pump, indigo electonic ignition, indigo FWC system.
I Just replaced fuel and oil hoses, fuel water separation filter, plugs, Oil and filter, flushed the FW lines.

The shut down occurs when underway with no obvious sign, just quits. When is running oil pressure is just below 40 psi and engine temp at 150. It takes few attempts to restart and it might go for another 5’, 10’ maybe 20’ before it stops again.

No water in the fuel at least in the water separator bowl so it sounds an electric issue to me although I have not checked the fuel vent line as suggested in another post but will do ASAP.

I have to add that I might have an alternator charging issue also which could be related to this problem.

The boat (Tartan 30) and engine are new to me but this issue was brought up by the PO when we got the boat last fall. I did find a loose grnd wire on the fuel pump and though that was it but when we went out last Sunday (first time this spring Finally!!) no problem getting out of the channel but coming back the engine stopped 3 times.

Thank you in advance for any input!!

Marco

[JOHN COOKSON]

Fuel system problems and ignition system problems can cause shut downs.
In my mind the first step is to figure out which system is causing the shut downs.

There is a history of coil progressive failure caused by the coil overheating due to the increased dwell time that comes with an EI. You have the classic symptoms of this scenario.

A good place to start is to check for spark immediately after a shutdown, before the coil has a chance to cool off. Pull the big wire out of the center of the distributor cap and hold it near ground (the engine) and turn the engine to see if there is a blue-white spark.

Others will have other approaches. Do whatever makes the most sense to you.

A BIG WELCOME TO THE FORUM.

ex TRUE GRIT

[Muntasel]

Thank you for the response. The coil route make sense to me And I will buy new one regardless wether mine is bad or not, and keep it as a spare.

[roadnsky]

COLD JOINT

Another WELCOME to the crew!

In your situation, there could be something else behaving like a failing coil.
This quote is from our leader (Don) and worth checking...

"...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 will burn out the coil or kill the batteries.

[JOHN COOKSON]

It's Not Good To Have Doubts When Out On The Water.......

Take this opportunity to learn if (a) the coil is at fault and (b) if the coil has a problem why it failed.

(a)We do not know if there is an ignition or fuel system problem yet. If there is an ignition system problem the coil is suspect. There are easy ways to to test to see if the coil is functional or not. Could be something else. (see post #3)

(b)To many volts to the coil when the engine is running (see post #1)?; something weird with the EI?

By pursuing this you will get to the root cause of the shutdowns and have full confidence in your engine when done.

Best of luck.

ex TRUE GRIT

[Muntasel]

Well I have a couple of things to try now for next time I head out to the boat thank you.
Oddly enough the engine starts right up and seems to hold idle indefinitely, I will try to let it run around 1800/2000 Rpm at the dock and check the coil spark if and when it quits. Getting to the root cause of all will definitely present other challenges for sure, but surely add to better understanding and confidence on this motor.
It’s Rainy and colder than typical is in this neck of the wood but I will report any findings as soon as I get a chance.
Marco

[scratchee]

Does your RPM gauge bounce around or does it show a steady reading? When I bought my boat the seller had recently installed a new tach, and apologized because it bounced around and he didn't know why. A couple years later a few problems led me to replace the coil, and that unexpectedly fixed the tach. I guess the coil was slowly failing that whole time.

[Ando]

Such an annoying issue, I know. If it’s not the ignition coil etc As indicated above, try cleaning/rebuilding the carb. That was what caused my same problem.

[tenders]

I agree this could easily be a coil issue, but wouldn't rule out a fuel starvation problem. I suggest adding a cheap fuel pressure gauge between the fuel pump and the carb to check it when the engine next fails. It is worthwhile even if it doesn't solve THIS issue.

[Muntasel]

No erratic RPM reading, the only gauge that lags a little is the oil pressure it does not have a smooth transition with an increase or decrease of RPM, could be the sending unit or the gauge itself. Carb cleaning would be a good thing to do regardless, the P.O. used the boat but not extensively so the engine had a lot of down time. I am heading out today and see what I can find the new coil might not get here till Monday. Thanks for all your help so far.

[Muntasel]

So I Don’t have A new coil yet (UPS Teased me with an early delivery notification which dis not happen)
But what I have checked today was fuel vent line which had no blockage...then looking at the coil:
it is a NAPA Product couple if things I measured the resistance on the secondary winding which is 9.18K Ohms kind in the lower end of the 9K-11k as recommended range by Don Moyer on his coil check tutorial video (much appreciated!).
There is also this additional resistor (DALE RH-50 Measured at 1.5 Ohms ) connected to the positive of the secondary winding. Not sure why they installed it, the coil itself has a labeled on the side ‘no external resistor required’ , any ideas?
Is this because I have electronic ignition? I doubt it. I will try the moyer’s coil (As soon as it gets here) and eliminate the resistor and hopefully this will be the end of this dilemma.
I tried to upload a picture of the coil set up but I am not sure if it will show.

[ronstory]

Yes, the resistor is actually it's because you have IE. The coil is likely NAPA IC14SB with 3.25 ohm primary coil resistance, but the ones I've measured are closer to 3.0 ohms.

The MM coil will be close to 4 ohms, which will reduce the current flowing through the IE. If you are using the standard Pertronix ignitor module, it has an upper limit of 4 amps that it can safely source.

If your alternator puts out 14.4 Volts (like mine) and you have 4 amp limit for the IE you need a 3.6 ohms to stay below that limit. Assuming your coil is "standard" resistor coil, it's not enough resistance to safely limit the current.

So don't remove the resistor until you get the MM coil.

[Peter]

The purpose of the ballast resistor is to limit current through the primary ignition circuit.

EI has a larger dwell angle than points do. This larger dwell angle leads to the current flowing in the primary circuit for more time.

This increased time results in more heating of the coil and excessive temperature in the coil will lead to coil failure. It is my understanding that the ballast resistor is there to protect the coil, not the EI module.

I have never previously read the suggestion that the igniter module has a 4 amp current limit - are you able to provide a reference?

When I first arrived on this forum I was instructed to check my coil voltage and resistance to determine whether I needed a ballast resistor. Note that it is the primary resistance you need to measure to determine whether the ballast is required.

Ndutton is the forum guru on this topic (and just a few others...)

Peter

[joe_db]

The purpose of the ballast resistor is to limit current through the primary ignition circuit.

EI has a larger dwell angle than points do. This larger dwell angle leads to the current flowing in the primary circuit for more time.

This increased time results in more heating of the coil and excessive temperature in the coil will lead to coil failure. It is my understanding that the ballast resistor is there to protect the coil, not the EI module.

I have never previously read the suggestion that the igniter module has a 4 amp current limit - are you able to provide a reference?

When I first arrived on this forum I was instructed to check my coil voltage and resistance to determine whether I needed a ballast resistor. Note that it is the primary resistance you need to measure to determine whether the ballast is required.

Ndutton is the forum guru on this topic (and just a few others...)

Peter

I don't know about 4 amps, but long ago we figured out it needs to be 4 ohms.

[ronstory]

The 4 amp limit for 4 & 6 cylinders is hard to find on the pertronix website since it's not included in the formal specs. I did manage to find it on the aussie version of their site. I also think there is one line mentioned in the written instructions... that come is in a lovely 4 point font.

http://www.pertronix.com.au/troubleshooting.html -> at the bottom

Four and six cylinder engines should not exceed 4 amps. Eight cylinder engines should not exceed 8 amps. If the total amperage in your system is higher than the amount recommended for your application, you should install a ballast resistor.

Example:
Voltage 12
Resistance 1.5
12 / 1.5 = 8
Total amperage is 8

I know this because I put a modern high performance coil on a modified IH Scout running a 392. About a year or so into running the coil with a pertronix it would have intermittent failures. After the 2nd pertronix module died, I started digging through all the docs and found the above reference. My coil measure out at 1.4 ohms and with a 14+V alternator... I was just over the limit, which caused a slow death. I added a ballast resistor and the third pertronix module has lasted over 15 years. Oh, and the same coil for entire time.

EDIT: I got curious and tried to find the same info on the main Pertronix site... and that section been truncated to just measuring the coil resistance and not why it's important. The Aussie site has the older version of the troubleshooting FAQ, without the fancy HTML expansion radio buttons.