Getting current from coil output but not from distributor wires to plugs

[cvile1617]

yup same ring. However, if the ring was not working then the coil would not be able to turn on and off- or am i barking up the wrong tree

I just took the coil lead to distributor and grounded near a good bear metal position on the engine and I get a consistent blue arch. Not a huge arch but appears strong

[cvile1617]

Is there anyway the distributor could be going to ground??

[cvile1617]

The A4 has started!!!!!!!!!!!!!!!!!!!!!

So my tach is connected to the coil. I disconnected one leg to gain more room on the coil + post so I could energize the coil at the engine to confirm not an ignition switch issue.

When I removed the neg side of the tach circuit the baby fired right up. I guess the tach must have a short some where and was going to ground.

Bottom line is new tach and we are hitting the water tomorrow

Thanks to everyone for your insight, patience and ideas. I never give up and I always want to know the why. Now I know

[Oldlaxer1]

Congrats! Enjoy the day!

[hanleyclifford]

Interesting Thread

Never run into a tach before that could ground a distributor enough to weaken a spark. Learned something new for the troubleshooting folder. Thanks. Edit: That said, I think we can see that a voltage check at coil+ from the git go might have revealed a weakness, maybe less than 9 volts? I have often seen an engine produce a spark that seems adequate but is not sufficient to get a spark thru compression. But this is the first time I have heard of a spark that can get to center of distributor but not jump to the cylinder terminals via the rotor. We keep learning.

[Dave Neptune]

cville, I tend to agree with Hanley on the tach shorting out. Was the tach working?
You mentioned room on the coil stud, how many wires are you supporting for current?

Check the main engine or block grounds too, if no block ground hook one up.


Did you ever check the actual voltage at the coil positive when cranking? A low voltage issue could easily create the problems listed here.

Good to hear it is running, however I'd do a few checks if the old tach was still working.

A good wiring procedure for the soil is one wire for manual fuel pumps and one (OPSS) for an electric pump. The tach if so equipped is OK but no other power should be taken from that circuit as it must run the instruments and the ignition. In some cases there will be a wire from the starter solenoid for direct voltage during cranking only.

Dave Neptune

[hanleyclifford]

Only what is necessary should be on coil+. Otherwise you are playing havoc with your voltage at coil +. Here's my current set up; disregard the wires to the left which are simply jointed at a convenient spot: The small black wire from the resistor runs to the (ignition circuit dedicated) amp gauge and the small white wire is bringing the current back to coil+. The large white wire feeds the gauges (including tach) which is not a big draw. The red and black for the EI run from coil+ and coil- respectively. The fat pink (#14) from coil+ runs to "R" at the starter. The green from coil - is the sender for the tach. All other users are fed from different circuits so as not to destabilize voltage at coil+.

[JOHN COOKSON]

Not So Fast Here

cville,
Check the main engine or block grounds too, if no block ground hook one up.
Did you ever check the actual voltage at the coil positive when cranking? A low voltage issue could easily create the problems listed here.
Good to hear it is running, however I'd do a few checks if the old tach was still working.
Dave Neptune

I agree that removing the tach from the circuit and having the engine start implies cause and effect.
I'd feel better if it could be moved closer to proven.
If the OP did a couple of three tests: (A) Shake the relevant wires around while the engine is running. Maybe removing the tach turned a cold connection into a hot wire. (B) Test the tach and the wire for grounding. If the tach was truly grounded why wasn't there an arc welder effect? Maybe there was a low resistance path to ground? (C) And for frosting on the cake measure the voltage at coil + while the engine is being cranked.

TRUE GRIT

Edit: Reinstalling the tach and having a no start would nail it down also.

[ndutton]

Only what is necessary should be on coil+. Otherwise you are playing havoc with your voltage at coil +

Categorically untrue for a well designed and properly installed wiring system that complies with accepted boating industry standards. It has been previously established on this forum several times, for example: http://www.moyermarine.com/forums/sh...7&postcount=66

There is no acceptable reason for voltage havoc at coil + or anywhere else for that matter. If there is, time to get your own house in order and stop suggesting it's normal* to others looking for help.

*If you add a load to a circuit and it affects the voltage greater than 3% (essential circuit) you need to redesign the entire circuit with larger wire so it doesn't. We've repeated this several times, obviously need to again.

What is so difficult in accepting the ABYC standard on wiring? Why does this keep coming up over and over? If it were different members, maybe but this isn't. Would it help if the standards information was posted by someone else?