Hi All,

While doing the dreaded spark plug change I noticed what appears to be a grounding wire on the firewall of the passenger side. Mine is fraying pretty bad and I was wondering what this wire is called, where it runs to, and what it controls (I guess also wondering how hard it is to replace).

Thanks!

 

I don't know what that wire is for but I'd just cut out the frayed part and splice in a new wire. The joints really should be soldered and just crimped for reliability. Just be sure to use good quality flexible wire that is at least as large as the original wire. I would use a piece of heat shrink tubing to cover the joints or just use one long piece to cover both joints.

 

Awesome, thanks!

As another thought (I think the other end is grounded to the back of the block) would a good idea be to also add a grounding strap from the same firewall location and run to a bolt in the head? I think I read somewhere someone mounted one end to the bolt that holds the transmission fluid tube to the head...

 

You can add an extra ground wires if you want to but I don't think it will really help anything. We used to run ground wires to all sorts of things like the doors and the hood in an effort to suppress Radio Frequency Interference but with the modern radios and modern auto electronics, it really doesn't seem to have any benefit today. I use this kind of stuff

. I pick it up for free at a couple of the surplus places that I deal with so I use it generously.

 

At the least ..... wrap it where it's chaffing on that edge. Likely it's being moved as the engine rocks on the mounts.

 

Thanks for the reply. What I meant was, instead of attempting to get to the end on the back of the engine block to replace the strap that's there (I'm sure the bolt is going to be fairly rusted as all the other bolts on my truck are), could I simply attach a new one to the head and firewall so when the stock one finally breaks the engine-to-firewall ground connection would still be intact?

Not so much as making more connections than already are there, but rather a backup for when the current strap finally corrodes to nothing (or I take it off since the new re-routed strap would suffice).

 

That strap really shouldn't be tight enough that it chafes. I'm wondering if you might have a broken motor mount that's letting the engine rock over further than it should. Check your motor mounts and just to be safe use a slightly longer strap.

 

Ideally that should work but to tell the truth, grounds are something of black art and I wonder WHY Ford choose to attach it to the firewall. Usually grounds straps are connected to the heaviest structure that is is nearby such as the frame or one of the starter attachment bolts. If you're sure that the bottom end is connected to the block, go ahead and connect the new one to the head but if you encounter any electrical problems then move it back to the original connection point. BTW use a flat washer and a lock washer on the bolt or nut that the strap is attached to and scrap the paint off of the metal surface, you don't want it to work loose and you want a good clean surface for the connection.