Starter Grounding

Two questions.

First, Is the starter grounded through the engine? (following the engine grounding path). I don't see a ground strap from the starter back to the engine mount / battery terminal.

Second, in the Firewall Forward instructions page 43-4 and 43-11 it appears that wire WH-K910 is grounded from the I terminal of the start contactor to a bolt (likely a grounding bolt) on the starter itself. What is the reasoning for this? Why not just ground the I terminal of the start contactor directly back to the firewall as opposed to running it all the way up to the starter? The only reason I could think is to verify the starter is grounded prior to activating the contactor, but that seems a bit unnecessary at first glance. I am hoping someone can shed some light on this. Thanks

Yes, the started is grounded through the engine block.

I don't know about the -14 plans but the other RV's require a grounding strap from the back of the engine to someplace on the firewall, typically a forest of tabs grounding block that also picks up the ground (-) for the battery.

You can see my ground straps in this picture:


(click to enlarge)

Ground

The engine will crank so much better with a dedicated ground from the starter to direct to the battery. My 10-1 0 320 would barely turn over without the ground strap.

mulde35d said:

Second, in the Firewall Forward instructions page 43-4 and 43-11 it appears that wire WH-K910 is grounded from the I terminal of the start contactor to a bolt (likely a grounding bolt) on the starter itself.

Click to expand...

Could this be a diode?

Or, a signal line to the starter solenoid?

No plans to look at, just shooting in the dark from your description of the wire in question.

Picture

Diagram Photo for clarity. This is both pages referenced above

Here is a short thread with a basic explanation.

http://www.vansairforce.com/community/showthread.php?t=143220&highlight=relay

If you are willing to spend some reading time, here is a thread that includes an in depth explanation (and debating) on the reason, and how it works.

http://www.vansairforce.com/community/showthread.php?t=135312&highlight=relay

Those threads answered the question. Much appreciated

I decided to add an extra ground - not from the starter though. I just ran a heavy cable from the location on the engine mount where the engine ground strap attaches back to the same location on the firewall where the battery ground attaches. This gives the engine/starter another path to ground in addition to the engine mount.