Anyone know 6.2L fuses for injectors and coils?
 

Does anyone know which fuses supply the coils (COPs) and injectors on the 6.2L (2011 F-250 4wd)? I have looked in the owner's manual and searched and cannot find this info.

I found an interesting video about using a current probe on the supply wire shared by all the coil primaries to try to isolate a coil problem. I'm having a misfire I can't isolate and I'd like to try this test this weekend. The video was for an older truck (5.4L) and thus the fuse box was quite different. Of course maybe the coils and injectors are no longer "low side switched" but it seems likely they would be.

This would be a lot easier than trying to access individual coils and/or injectors!

Thanks for any info!

A bad fuse would not cause a misfire.. Have you changed out the spark plugs yet?

thanks
 

I think you misunderstood. I'm not trying to check the fuse. I am trying to use the fuse as an easy way to access the power lead going to ALL the COP primaries. I will then connect a current probe and an oscilloscope. You can then see the current waveforms for each coil. If turns of a coil are shorted, it shows up quite well. You can do the same thing for injectors. This is a lot easier than trying to get to the wiring for each coil or each injector, which are buried under the air box.

You can see the ScannerDanner video here:
I have replaced the spark plugs and wires, and tried changing out 1/2 set of coils at a time and it has not fixed the problem. These were cheap ebay coils, of unknown quality, because the OEM ones are at least $75 each. On a 5.4 they are much cheaper.

Thanks for the reply!

if you understood How a coil works and how its made...


you would not go cheap.

if short on Cash.. get used ones from a wrecking yard.. (FoMoCo).

No fuses .. direct from computer to coil and injectors.. just unplug
my opinion.

thank you, i do
 

Thanks for your reply. I happen have a degree in electrical engineering, and I actually have a very good idea how coils work and how they are made :)

Quality coils are $70 each. That's $560 for a set. Would it not make more sense to do what this video shows (since I have a scope and current probe), rather than randomly replace coils with ones that might also be bad? The video idea is quite clever and shows ScannerDanner is a good troubleshooter.

Since I got 4 ebay coils for $80, I thought that was a pretty good gamble. I'm sure I can resell them and get half my money back.

Are you saying you have a wiring diagram that shows the injectors are "high-side switched" (get +V from the PCM) with no fuses? That would be somewhat surprising.

Thanks again for taking the time to make suggestions.

Fuse for coils, access to probe injector current
 

I'll answer my own question on this, in case it helps someone else out...

With the help of a new Alldata subscription, I learned:

On the 6.2L trucks, fuse F36 (in box by air cleaner) feeds all ignition coils (COPs). You can build a jumper for this fuse and conveniently use a current probe to see current to ALL coil primaries at one time. I triggered my scope off coil #5 voltage because it was close.

Firing order on 6.2L is 1-3-7-2-6-5-4-8 before you ask!

The injectors are tougher. They are fed by fuse F66, through the fuel pump relay, but this also feeds the fuel pump control module and the fuel pump so isn't very useful. I did find a solution...

Connector C1168, fastened by the battery, is a big connector with only a few pins populated. One of the four BIG pins on the outside corners is BLUE (a very icky blue) and this is the wire feeding all the injectors. On the other side of the connector it is VIOLET/GREEN. It is pin #9 and pin numbers are molded into the connector shell if you look carefully.

These two points allow you to easily view currents to ALL injectors and ALL coils, which may help you diagnose problems in those areas.

Good luck!