I have a 2003 XJ8, with a burned fuel pump. In fact, the 2-pin connector is also burned. I have a replacement pump, but noticed a black box, in-line with the fuel pimp wires (in the tank), and I don't know what it is. I suspect that it's electrical noise filtering, but should find out for sure. I don't want to change just the pump if this is also bad. Does anybody know what this part does? Picture attached.

 

Noise filter. There was a post about it some time ago.

 

I did a search for "fuel pump" & "noise filter", and couldn't find it. Am I correct in assuming that it's just a ferrite bead around the wires? If so, I can just check for continuity, as ferrites usually don't burn.

 

It's most likely something like a T or a Pi filter - a pair of inductors surrounding a cap to ground or a pair capacitors to ground with an inductor in-between or equivalent. See picture.

 

You can look at the patent filed by the manufacturer, Walbro.

Denso has a patent on in-pump electrical noise filtering, so no doubt Walbro had to go external.

A ferrite bead would do just as well on the external wiring leading up to the tank if you want to just bypass the "black box". Those link leads are expensive, and prone to failure at the connectors.

They must have some effect on power handling because it is *always* the ground side connectors that burn up.

Mine are simply deleted without any ferrite bead or any other noise reduction devices and the sound system works just fine ... the rare times that it is in use.

 

We decided to replace the link lead, as the wire was burned so badly, we couldn't get solder to stick. Maybe I'll get to drive it today!Thanks for all the help! Bob