2014 F250xa No Spark Cylinder 1 and 6

[panasonic]

Yes, but its the detail of "tells the coil driver" I'm wondering about.

Your drawing - if I'm understanding correctly -
shows it done with a 5V+ control signal
originating within the ECM

(so the ECM is switching a current that it supplies,
not, as in some other applications, switching the "ground" for the familiar red/yellow 12V)

is that right?

I follow this guy on YouTube, he does a pretty god job on explaining the basics. if you search his channel he shows the waveform of ignition coils.

https://youtu.be/4-BVb8Z6am0?si=wD0N2kpSYbspF_7S

Then a much more detailed video. You can get a really small portable scope now for cheap.

https://youtu.be/zQXeMqlBagI?si=UvqFafFFFj03t1EU

[fairdeal]

Always great to hear a successful outcome!

[grouper249]

Extremely happy to report the coil connector was at fault. Can’t thank you all enough for helping me. And for all others, the connector I put above is an exact match. Fit like a glove. I now have spark on #1 cylinder. Would take her out tomorrow but it’s supposed to blow 30

[grouper249]

Only the #1 cylinder is not firing. Dismantled the connector that attaches to #1 coil assembly this evening and noticed the female connector that the coil “pins” go into were very loose. Ended up breaking one of the wires trying to remove so now need to wait for new connector, one I provided in link above, to arrive.

[boscoe99]

Are two cylinders still not firing or has it been narrowed down to just one?

[grouper249]

Well, I may have found it. This is the closest I can find for coil assembly side. Going to order and will report back if it’s the correct connector and whether it fixes the problem. Thank you all very much for your help so far.

https://www.bmotorsports.com/shop/pr...oducts_id/4653

[99yam40]

I would try cleaning the connectors to see if that lowered the resistance on #1.
or measure the voltage at the different places you can to see if you can ID the place that is the problem

[fairdeal]

I am not aware of Yamaha selling individual wiring connectors
but the connectors they use are standard parts sourced from several Japanese electronic suppliers,
frequently Sumitomo and Furukawa
which if you Google, are available from several online sellers

From looking at photos of the F250 spark coil,
the connector "looks to be" a Sumitomo HX 090
but I can't guarantee that...

And of course the problem might be at the other end - the ECM connector.
I haven't looked at that -
but I suspect it may be a challenge to identify/source

[grouper249]

So I’ve now confirmed continuity to ECM and fuse box as well as ground from coil connector on #1. Also measured resistance from terminal 1 of the connector to ECM and compared to other operating coils. The #1 cylinder had a resistance of 1.8 while all other there were at .6, on the 200ohm scale. It seems as though I have a faulty connection on the connector itself. Anyone know if I can buy just a connector vs an entire wiring harness and simply reattach new connector?

[grouper249]

I'm beginning to wonder if excessive resistance exists in the 5V wire originating from the ECU to the Coil assembly, thus causing that coil to not receive the expected 5V. Seems as though i could measure for 5 volts on Terminal 1 of the coil connector to verify, by way of the stationary test on cylinder #1? If not, it would point to the wire or the connector that attaches to the coil assembly. I'm no electrician, but suspect simply testing for continuity is just not enough in this scenario?

[boscoe99]

[boscoe99]

Thank you all for the responses. It's starting to piece together in my brain. Is the Coil Driver physically located on the Coil itself? Are their specific "upstream" sensors that would/could impact the ECU signal to the Coil Driver? Is the best way to confirm coil driver function via the "crafty person" bench test?

Yes. The coil driver is part of the assembly that sits on top of the spark plug.

The ECU is sending signals to all six of the coil on plug assemblies. To cause the six plugs to fire at specific times. I cannot imagine any sensors that would be telling coils 1 and 6 to not fire while not affecting the other 4 coils.

[boscoe99]

Yes, but its the detail of "tells the coil driver" I'm wondering about.

Your drawing - if I'm understanding correctly -
shows it done with a 5V+ control signal
originating within the ECM

(so the ECM is switching a current that it supplies,
not, as in some other applications, switching the "ground" for the familiar red/yellow 12V)

is that right?

I like to think of a driver as a relay. A relay that is being switched on and off by the ECU. To open and close the primary ignition coil ground path.

5 volts from the ECU in the example above. To the driver/relay. Not switching a ground as is in the modus operandi of many Yamaha components.

Wish that I had a motor with a coil on plug ignition system. I might use my Oscope tablet to try and view the electrical signal from the ECU to the coil on plug.

[grouper249]

Thank you all for the responses. It's starting to piece together in my brain. Is the Coil Driver physically located on the Coil itself? Are their specific "upstream" sensors that would/could impact the ECU signal to the Coil Driver? Is the best way to confirm coil driver function via the "crafty person" bench test?

[fairdeal]

The other side of the primary coil is grounded but through a coil driver.

The ECU tells the coil driver when to disconnect the ground to the primary coil. At which time the spark plug fires.

Yes, but its the detail of "tells the coil driver" I'm wondering about.

Your drawing - if I'm understanding correctly -
shows it done with a 5V+ control signal
originating within the ECM

(so the ECM is switching a current that it supplies,
not, as in some other applications, switching the "ground" for the familiar red/yellow 12V)

is that right?