Good Morning All y'all good peoples...

Since getting this car one of the FIRST things I remembered hearing was about the "dreaded shielded wire"... I think it was Warren who mentioned it. Made me nervous... So, just because (which was my reason for taking on the project of the sitting for 12yrs XJS, living in NYC, never intending on driving here - at all - 4 cars later, lol don't get me started) I went and got myself 25ft of the stuff and it has been sitting on the shelf since.

When I was working on replacing coils and coil plugs and other wire related stuffs I came across the spade connection on the LH side of the engine of the dreaded shielded wire and, wire exposed, not looking tooooo healthy, I just taped it up well and acted like I didn't see it. The whole idea of messing around with it freaked and freaks me out... But, it doesn't freak me out more than being on the side of the road in Maine. The electrical gremlins I dealt with these last 2 days showed me how quickly a nice drive can go funny. So here I am

Has anyone don't this and could ya help walk me thru it? What special tools or bit and bobs will I need? I'll start gathering them up...

 

I can't say that I'm sure what you are asking, but as for replacing shielded wire I was successful in making my own. I took a piece of insulated copper wire, wrapped a few layers of aluminum foil around it (in a spiral fashion), putting a small length of un-insulated copper wire on the outside of the shielding, used heat shrink to secure it, and all has been well for five years. If this isn't clear I can probably sketch is out and post it as a graphic.

No special tools are required, just a solder gun/iron and some heat shrink tubing...and the correct sized spade connectors.

In my years of working on my 1987 V-12, I've learned that crimping wires is not the way to go. Solder each and every connection (shielded wire or otherwise) you can.

Hope this helps...

John
1987 XJ-S V12

 

Hey John... Thanks for your reply!

I have like 25ft of shielded wire... Wondering if there are plugs I need to connect the wire properly to the Marelli ECU? Also wondering if there is a special way the shield (what the copper is shielded by) is connected at the ECU or at the spade end? I've never wired anything using shielded wire and understood it to be a delicate process... Will I be removing the clipped in connector at the ECU end and inserting one that I purchased in its place? What size and style connector will I need, and such? These sorts of questions.

Maybe I can and should just clip the shielded wire that's there now and just reuse what I have, solidifying the connection cutting out the damaged bit right at the spot where the spade connects near the fuel rail?

Hahahaha, maybe I should youtube shielded wire and see just what I'm getting into with some of this!

 

One caveat to my response, I have no experience with a Marelli ignition.

Don't make this more difficult that it it. In shielded wiring there are two leads (terminations) on each end, one for the core wire (the wire in the middle of the insulation) and one for the shielded wire. Just put appropriate connectors on each termination, plug them in and your done.

The size and style of the connectors isn't all that important. They don't even have to be the same style/size on each end, but you want to make sure they form a snug fit so you don't have to worry about a connector popping out.

Hope this helps!

John

 

It does help. Thank you John. Your advise is right. Since posting this I've read a bit more here and in other places about dealing with shielded wire and it doesn't need to be as difficult... I have had some dealings with what I think is shielded wire, perhaps of a different type, on this car and I wasn't able to get it right - the speedO sensor in the differential. 2 or 3 wires there and I think the shielded insulation portion might play more of an integral role in the signal?, anyways.

I will post a photo of what I'm looking at when I get to it. There are a good few wires in the area that need to be rewrapped, we routed and re-examined just to be sure that connections are clean, strong, good and this shielded wire is one of them. The spade terminal has wire, the core wire, exposed with the spade kinda flopping around, the black plastic cover is all brittle and shatted-ish, and I have not seen the termination of the ground wire in that area.

I was and am still unclear on how the other end of this wire connects into the ECU and, IF I were to completely replace the wire soup to nutts (what I thought I might need to do originally), WHAT I would need for a completely new replacement connector/clip/plug lead at the ECU multiplug end...? Seems I won't be going that far into this after all. I would still like to know the type of connector at the ecu tho - just because.

Thanks for your help!

 

I'm afraid this is where my usefulness comes to an end, simply because I have no experience with a Marelli ignition. The Lucas (mine) and Marelli (yours) are really two different animals. While they serve the same function, they go about it in two separate ways.

I can suggest that the only wires that need replacing are in the engine compartment. I wouldn't think that the cabling from the engine compartment to the ECU would be an issue, then again my ECU is in the boot, and I'm not sure where the ECU in a Marelli is.

Good luck with it, I wish I could help more.

John

 

I believe these wires are the main ignition (key) feed for 12v input to damn near everything involved in the ignition (spark) situation... All of these wires come together and branch. I don't like that design,,, but don't know what to do instead. Resistance here must have been pretty high. Soldering time!

Electrical gurus out there,,, I'm all yours!

 

It's basically a six wire 12v junction and I need to figure out how to re-JOIN them all together in the best possible and most durable way... Believe it or not,,, everything else around it is solid...

 

You will find plenty of videos on soldering. Here's a good one that really makes it easy to get the solder in there:


I would buy a nice solder gun, not the cheap $11 kind, you'll find that it comes in handy.

 

Yup. I think I'm getting better at this....
I'll write up a little more a little later.
I wonder IF that strange joint was a factory thing or did someone "fix" it - that way...

​​​​​​used a mini butane lighter...

 

I'm wondering if anyone has ever thought it necessary, beneficial or the right thing to redo this arrangement?

My problem (I don't think) was my shielded wire at all (although I will go back and recrimp spades and connections). Again, I think that my problem had to go with a crusty and corroded connection where these six ignition related wires come together. It looks like on one 12v source, the ignition key controlled power switch, both coils, the Marelli ignition ECU and both amps are powered. This is where I had a problem. I don't know if it was a factory connection, or something someone did later, but it doesn't seem like the best arrangement. The connection, although it's hard to decipher from the ED schematic, is in the wire loom on the LH side of the engine, running over the intake between injectors 4 and 5. The branch that goes outta to the coils.

Has anyone used dedicated 12v to power the individual components and in folks opinion, would that be a better arrangement? Seems like this way there could be wild fluctuations in the 5 ignition components...


Junction