Taking bits off my 86 like valve covers, coil, hoses to do some cleanup and hose replacement work.

Never noticed but the water rail has a small pigtail ground wire ftom its firewall end to the big ground bundle at the end of the water rail.

Always have abided by wise advice to keep that big bundle connection clean and tight...but occurred to me today that the little pigtail end that secures to the rail is very important.

It is the ground connection for many of the water rail sensors.

Add it to your grounds list 😊

 

yes, it is a Ground Strap.

 

Yes, and it's impossible to over stress how important it is for the Series 3 XJ to have all the ground straps present and in extremely good conditions through the length of the conductor and at the terminals.